From fe4928122cd35a06cf2c120bb0360e23022b6563 Mon Sep 17 00:00:00 2001
From: Namami Shanker <namami2011@gmail.com>
Date: Mon, 11 Jul 2022 20:40:43 +0530
Subject: [PATCH 01/37] FIX: Import f2py2e rather than f2py for run_main

---
 numpy/distutils/command/build_src.py | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/numpy/distutils/command/build_src.py b/numpy/distutils/command/build_src.py
index bf3d03c70e44..7786b949a160 100644
--- a/numpy/distutils/command/build_src.py
+++ b/numpy/distutils/command/build_src.py
@@ -558,8 +558,8 @@ def f2py_sources(self, sources, extension):
                    and not skip_f2py:
                 log.info("f2py:> %s" % (target_file))
                 self.mkpath(target_dir)
-                import numpy.f2py
-                numpy.f2py.run_main(f2py_options + ['--lower',
+                from numpy.f2py import f2py2e
+                f2py2e.run_main(f2py_options + ['--lower',
                                                 '--build-dir', target_dir]+\
                                 ['-m', ext_name]+f_sources)
             else:

From 6b1475e17cb2e84910fb64358058cc098a80d6c2 Mon Sep 17 00:00:00 2001
From: Namami Shanker <namami2011@gmail.com>
Date: Tue, 12 Jul 2022 19:31:20 +0530
Subject: [PATCH 02/37] FIX: Import f2py2e instead of f2py

---
 numpy/distutils/command/build_src.py | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/numpy/distutils/command/build_src.py b/numpy/distutils/command/build_src.py
index 7786b949a160..7303db124cc8 100644
--- a/numpy/distutils/command/build_src.py
+++ b/numpy/distutils/command/build_src.py
@@ -539,8 +539,8 @@ def f2py_sources(self, sources, extension):
             if (self.force or newer_group(depends, target_file, 'newer')) \
                    and not skip_f2py:
                 log.info("f2py: %s" % (source))
-                import numpy.f2py
-                numpy.f2py.run_main(f2py_options
+                from numpy.f2py import f2py2e
+                f2py2e.run_main(f2py_options
                                     + ['--build-dir', target_dir, source])
             else:
                 log.debug("  skipping '%s' f2py interface (up-to-date)" % (source))

From 91f3825346dea3537f2bf1ce9fb4ca2b97b173ce Mon Sep 17 00:00:00 2001
From: Rohit Goswami <rog32@hi.is>
Date: Thu, 24 Aug 2023 22:44:55 +0000
Subject: [PATCH 03/37] ENH: Add F2PY back-end work from gh-22225

Co-authored-by: NamamiShanker <NamamiShanker@users.noreply.github.com>
---
 numpy/f2py/backends/__init__.py      |   4 +
 numpy/f2py/backends/backend.py       | 125 +++++++++++
 numpy/f2py/backends/meson_backend.py | 310 +++++++++++++++++++++++++++
 3 files changed, 439 insertions(+)
 create mode 100644 numpy/f2py/backends/__init__.py
 create mode 100644 numpy/f2py/backends/backend.py
 create mode 100644 numpy/f2py/backends/meson_backend.py

diff --git a/numpy/f2py/backends/__init__.py b/numpy/f2py/backends/__init__.py
new file mode 100644
index 000000000000..7c93fa16a715
--- /dev/null
+++ b/numpy/f2py/backends/__init__.py
@@ -0,0 +1,4 @@
+from .backend import Backend
+from .meson_backend import MesonBackend
+
+backends = {"meson": MesonBackend}
diff --git a/numpy/f2py/backends/backend.py b/numpy/f2py/backends/backend.py
new file mode 100644
index 000000000000..30f0046c9f3e
--- /dev/null
+++ b/numpy/f2py/backends/backend.py
@@ -0,0 +1,125 @@
+from __future__ import annotations
+
+from pathlib import Path
+from abc import ABC, abstractmethod
+
+import numpy
+import numpy.f2py as f2py
+
+
+class Backend(ABC):
+    """
+    Superclass for backend compilation plugins to extend.
+
+    """
+
+    def __init__(
+        self,
+        module_name,
+        fortran_compiler: str,
+        c_compiler: str,
+        f77exec: Path,
+        f90exec: Path,
+        f77_flags: list[str],
+        f90_flags: list[str],
+        include_paths: list[Path],
+        include_dirs: list[Path],
+        external_resources: list[str],
+        linker_libpath: list[Path],
+        linker_libname: list[str],
+        define_macros: list[tuple[str, str]],
+        undef_macros: list[str],
+        debug: bool,
+        opt_flags: list[str],
+        arch_flags: list[str],
+        no_opt: bool,
+        no_arch: bool,
+    ) -> None:
+        """
+        The class is initialized with f2py compile options.
+        The parameters are mappings of f2py compilation flags.
+
+        Parameters
+        ----------
+        module_name : str
+                The name of the module to be compiled. (-m)
+        fortran_compiler : str
+                Name of the Fortran compiler to use. (--fcompiler)
+        c_compiler : str
+                Name of the C compiler to use. (--ccompiler)
+        f77exec : Pathlike
+                Path to the fortran compiler for Fortran 77 files (--f77exec)
+        f90exec : Pathlike
+                Path to the fortran compiler for Fortran 90 and above files (--f90exec)
+        f77_flags : list
+                List of flags to pass to the fortran compiler for Fortran 77 files (--f77flags)
+        f90_flags : list
+                List of flags to pass to the fortran compiler for Fortran 90 and above files (--f90flags)
+        include_paths : list
+                Search include files from given directories (--include-paths)
+        include_dirs : list
+                Append directory <dir> to the list of directories searched for include files. (-I<dir>)
+        external_resources : list
+                Link the extension module with <resource> (--link-<resource>)
+        linker_libname : list
+                Use the library when linking. (-l<libname>)
+        define_macros : list
+                Define <macro> to <value> if present else define <macro> to true (-D)
+        undef_macros : list
+                Undefine <macro> (-U)
+        linker_libpath : list
+                Add directory to the list of directories to be searched for `-l`. (-L)
+        opt_flags : list
+                Optimization flags to pass to the compiler. (--opt)
+        arch_flags : list
+                Architectire specific flags to pass to the compiler (--arch)
+        no_opt : bool
+                Disable optimization. (--no-opt)
+        no_arch : bool
+                Disable architecture specific optimizations. (--no-arch)
+        debug : bool
+                Enable debugging. (--debug)
+
+        """
+        self.module_name = module_name
+        self.fortran_compiler = fortran_compiler
+        self.c_compiler = c_compiler
+        self.f77exec = f77exec
+        self.f90exec = f90exec
+        self.f77_flags = f77_flags
+        self.f90_flags = f90_flags
+        self.include_paths = include_paths
+        self.include_dirs = include_dirs
+        self.external_resources = external_resources
+        self.linker_libpath = linker_libpath
+        self.linker_libname = linker_libname
+        self.define_macros = define_macros
+        self.undef_macros = undef_macros
+        self.debug = debug
+        self.opt_flags = opt_flags
+        self.arch_flags = arch_flags
+        self.no_opt = no_opt
+        self.no_arch = no_arch
+
+    def numpy_install_path(self) -> Path:
+        """
+        Returns the install path for numpy.
+        """
+        return Path(numpy.__file__).parent
+
+    def numpy_get_include(self) -> Path:
+        """
+        Returns the include paths for numpy.
+        """
+        return Path(numpy.get_include())
+
+    def f2py_get_include(self) -> Path:
+        """
+        Returns the include paths for f2py.
+        """
+        return Path(f2py.get_include())
+
+    @abstractmethod
+    def compile(self, fortran_sources: Path, c_wrapper: Path, build_dir: Path) -> None:
+        """Compile the wrapper."""
+        pass
diff --git a/numpy/f2py/backends/meson_backend.py b/numpy/f2py/backends/meson_backend.py
new file mode 100644
index 000000000000..df0d1b4fdb8b
--- /dev/null
+++ b/numpy/f2py/backends/meson_backend.py
@@ -0,0 +1,310 @@
+from __future__ import annotations
+
+import os
+import errno
+import shutil
+import subprocess
+from pathlib import Path
+
+from .backend import Backend
+from string import Template
+
+
+class MesonTemplate:
+    """Template meson build file generation class."""
+
+    def __init__(
+        self,
+        module_name: str,
+        numpy_install_path,
+        numpy_get_include: Path,
+        f2py_get_include: Path,
+        wrappers: list[Path],
+        fortran_sources: list[Path],
+        dependencies: list[str],
+        include_path: list[Path],
+        optimization_flags: list[str],
+        architecture_flags: list[str],
+        f77_flags: list[str],
+        f90_flags: list[str],
+        linker_libpath: list[Path],
+        linker_libname: list[str],
+        define_macros: list[tuple[str, str]],
+        undef_macros: list[str],
+    ):
+        self.module_name = module_name
+        self.numpy_install_path = numpy_install_path
+        self.build_template_path = (
+            numpy_install_path / "f2py" / "backends" / "src" / "meson.build.src"
+        )
+        self.sources = fortran_sources
+        self.numpy_get_include = numpy_get_include
+        self.f2py_get_include = f2py_get_include
+        self.wrappers = wrappers
+        self.dependencies = dependencies
+        self.include_directories = include_path
+        self.substitutions = {}
+        self.optimization_flags = optimization_flags
+        self.architecture_flags = architecture_flags
+        self.fortran_flags = f77_flags + f90_flags
+        self.linker_libpath = linker_libpath
+        self.linker_libname = linker_libname
+        self.define_macros = define_macros
+        self.undef_macros = undef_macros
+        self.pipeline = [
+            self.initialize_template,
+            self.global_flags_substitution,
+            self.sources_substitution,
+            self.dependencies_substitution,
+            self.include_directories_subtitution,
+            self.linker_substitution,
+            self.macros_substitution,
+        ]
+
+    @property
+    def meson_build_template(self) -> str:
+        if not self.build_template_path.is_file():
+            raise FileNotFoundError(
+                errno.ENOENT,
+                f"Meson build template {self.build_template_path.absolute()} does not exist.",
+            )
+        return self.build_template_path.read_text()
+
+    def initialize_template(self) -> None:
+        """Initialize with module name and external NumPy and F2PY C libraries."""
+        self.substitutions["modulename"] = self.module_name
+        self.substitutions["numpy_get_include"] = self.numpy_get_include.absolute()
+        self.substitutions["f2py_get_include"] = self.f2py_get_include.absolute()
+
+    def sources_substitution(self) -> None:
+        self.substitutions["source_list"] = ",".join(
+            ["'" + str(source.absolute()) + "'" for source in self.sources]
+        )
+        self.substitutions["wrappers"] = ",".join(
+            ["'" + str(wrapper.absolute()) + "'" for wrapper in self.wrappers]
+        )
+
+    def dependencies_substitution(self) -> None:
+        self.substitutions["dependencies_list"] = ", ".join(
+            [f"dependency('{dependecy}')" for dependecy in self.dependencies]
+        )
+
+    def include_directories_subtitution(self) -> None:
+        self.substitutions["include_directories_list"] = ", ".join(
+            [
+                f"include_directories('{include_directory}')"
+                for include_directory in self.include_directories
+            ]
+        )
+
+    def global_flags_substitution(self) -> None:
+        fortran_compiler_flags = (
+            self.fortran_flags + self.optimization_flags + self.architecture_flags
+        )
+        c_compiler_flags = self.optimization_flags + self.architecture_flags
+        self.substitutions["fortran_global_args"] = fortran_compiler_flags
+        self.substitutions["c_global_args"] = c_compiler_flags
+
+    def macros_substitution(self) -> None:
+        self.substitutions["macros"] = ""
+        if self.define_macros:
+            self.substitutions["macros"] = ",".join(
+                f"'-D{macro[0]}={macro[1]}'" if macro[1] else f"-D{macro[0]}"
+                for macro in self.define_macros
+            )
+        if self.undef_macros:
+            self.substitutions["macros"] += "," + ",".join(
+                f"'-U{macro}'" for macro in self.undef_macros
+            )
+
+    def linker_substitution(self) -> None:
+        self.substitutions["linker_args"] = ""
+        if self.linker_libpath:
+            linker_libpath_subs = ",".join(
+                f"-L{libpath}" for libpath in self.linker_libpath
+            )
+            self.substitutions["linker_args"] += linker_libpath_subs
+        if self.linker_libname:
+            linker_libname_subs = ",".join(
+                f"-l{libname}" for libname in self.linker_libname
+            )
+            self.substitutions["linker_args"] += f",{linker_libname_subs}"
+
+    def generate_meson_build(self) -> str:
+        for node in self.pipeline:
+            node()
+        template = Template(self.meson_build_template)
+        return template.substitute(self.substitutions)
+
+
+class MesonBackend(Backend):
+    def __init__(
+        self,
+        module_name: str = "untitled",
+        fortran_compiler: str = None,
+        c_compiler: str = None,
+        f77exec: Path = None,
+        f90exec: Path = None,
+        f77_flags: list[str] = None,
+        f90_flags: list[str] = None,
+        include_paths: list[Path] = None,
+        include_dirs: list[Path] = None,
+        external_resources: list[str] = None,
+        linker_libpath: list[Path] = None,
+        linker_libname: list[str] = None,
+        define_macros: list[tuple[str, str]] = None,
+        undef_macros: list[str] = None,
+        debug: bool = False,
+        opt_flags: list[str] = None,
+        arch_flags: list[str] = None,
+        no_opt: bool = False,
+        no_arch: bool = False,
+    ) -> None:
+        self.meson_build_dir = "builddir"
+        if f77_flags is None:
+            f77_flags = []
+        if include_paths is None:
+            include_paths = []
+        if include_dirs is None:
+            include_dirs = []
+        if external_resources is None:
+            external_resources = []
+        if linker_libpath is None:
+            linker_libpath = []
+        if linker_libname is None:
+            linker_libname = []
+        if define_macros is None:
+            define_macros = []
+        if undef_macros is None:
+            undef_macros = []
+        if f77_flags is None:
+            f77_flags = []
+        if f90_flags is None:
+            f90_flags = []
+        if opt_flags is None:
+            opt_flags = []
+        if arch_flags is None:
+            arch_flags = []
+        super().__init__(
+            module_name,
+            fortran_compiler,
+            c_compiler,
+            f77exec,
+            f90exec,
+            f77_flags,
+            f90_flags,
+            include_paths,
+            include_dirs,
+            external_resources,
+            linker_libpath,
+            linker_libname,
+            define_macros,
+            undef_macros,
+            debug,
+            opt_flags,
+            arch_flags,
+            no_opt,
+            no_arch,
+        )
+
+        self.wrappers: list[Path] = []
+        self.fortran_sources: list[Path] = []
+        self.template = Template(self.fortran_sources)
+
+    def _get_optimization_level(self):
+        if self.no_arch and not self.no_opt:
+            return 2
+        elif self.no_opt:
+            return 0
+        return 3
+
+    def _set_environment_variables(self) -> None:
+        if self.fortran_compiler:
+            os.putenv("FC", self.fortran_compiler)
+        elif self.f77exec:
+            os.putenv("FC", self.f77exec)
+        elif self.f90exec:
+            os.putenv("FC", self.f90exec)
+        if self.c_compiler:
+            os.putenv("CC", self.c_compiler)
+
+    def _move_exec_to_root(self, build_dir: Path):
+        walk_dir = build_dir / self.meson_build_dir
+        path_objects = walk_dir.glob(f"{self.module_name}*.so")
+        for path_object in path_objects:
+            shutil.move(path_object, Path.cwd())
+
+    def _get_build_command(self):
+        return [
+            "meson",
+            "setup",
+            self.meson_build_dir,
+            "-Ddebug=true" if self.debug else "-Ddebug=false",
+            f"-Doptimization={str(self._get_optimization_level())}",
+        ]
+
+    def load_wrapper(self, wrappers: list[Path]) -> None:
+        self.wrappers = wrappers
+
+    def load_sources(self, fortran_sources: list[Path]) -> None:
+        for fortran_source in fortran_sources:
+            fortran_source = Path(fortran_source)
+            if not fortran_source.is_file():
+                raise FileNotFoundError(
+                    errno.ENOENT, f"{fortran_source.absolute()} does not exist."
+                )
+            self.fortran_sources.append(fortran_source)
+
+    def write_meson_build(self, build_dir: Path) -> None:
+        """Writes the meson build file at specified location"""
+        meson_template = MesonTemplate(
+            self.module_name,
+            super().numpy_install_path(),
+            self.numpy_get_include(),
+            self.f2py_get_include(),
+            self.wrappers,
+            self.fortran_sources,
+            self.external_resources,
+            self.include_paths + self.include_dirs,
+            optimization_flags=self.opt_flags,
+            architecture_flags=self.arch_flags,
+            f77_flags=self.f77_flags,
+            f90_flags=self.f90_flags,
+            linker_libpath=self.linker_libpath,
+            linker_libname=self.linker_libname,
+            define_macros=self.define_macros,
+            undef_macros=self.undef_macros,
+        )
+        src = meson_template.generate_meson_build()
+        meson_build_file = build_dir / "meson.build"
+        meson_build_file.write_text(src)
+        return meson_build_file
+
+    def run_meson(self, build_dir: Path):
+        self._set_environment_variables()
+        completed_process = subprocess.run(self._get_build_command(), cwd=build_dir)
+        if completed_process.returncode != 0:
+            raise subprocess.CalledProcessError(
+                completed_process.returncode, completed_process.args
+            )
+        completed_process = subprocess.run(
+            ["meson", "compile", "-C", self.meson_build_dir], cwd=build_dir
+        )
+        if completed_process.returncode != 0:
+            raise subprocess.CalledProcessError(
+                completed_process.returncode, completed_process.args
+            )
+
+    def compile(
+        self,
+        f77_sources: list[Path],
+        f90_sources: list[Path],
+        object_files: list[Path],
+        wrappers: list[Path],
+        build_dir: Path,
+    ) -> None:
+        self.load_wrapper(wrappers)
+        self.load_sources(f77_sources + f90_sources + object_files)
+        self.write_meson_build(build_dir)
+        self.run_meson(build_dir)
+        self._move_exec_to_root(build_dir)

From a0b01c38872b71d901aa281676bd17547d4f1579 Mon Sep 17 00:00:00 2001
From: Rohit Goswami <rog32@hi.is>
Date: Thu, 24 Aug 2023 22:46:56 +0000
Subject: [PATCH 04/37] ENH: Add meson skeleton from gh-2225

Co-authored-by: NamamiShanker <NamamiShanker@users.noreply.github.com>
---
 numpy/f2py/backends/src/meson.build.src | 22 ++++++++++++++++++++++
 1 file changed, 22 insertions(+)
 create mode 100644 numpy/f2py/backends/src/meson.build.src

diff --git a/numpy/f2py/backends/src/meson.build.src b/numpy/f2py/backends/src/meson.build.src
new file mode 100644
index 000000000000..8d2ce5fde994
--- /dev/null
+++ b/numpy/f2py/backends/src/meson.build.src
@@ -0,0 +1,22 @@
+project('${modulename}', 'c',
+  version : '0.1',
+  default_options : ['warning_level=2'])
+
+add_languages('fortran')
+
+add_global_arguments(${c_global_args}, language: 'c')
+add_global_arguments(${fortran_global_args}, language: 'fortran')
+
+py_mod = import('python')
+py3 = py_mod.find_installation('python3')
+py3_dep = py3.dependency()
+message(py3.path())
+message(py3.get_install_dir())
+
+incdir_numpy = '${numpy_get_include}'
+
+incdir_f2py = '${f2py_get_include}'
+
+inc_np = include_directories(incdir_numpy, incdir_f2py)
+
+py3.extension_module('${modulename}', ${wrappers}, ${source_list}, incdir_f2py+'/fortranobject.c', include_directories: [inc_np, ${include_directories_list}], dependencies : [py3_dep, ${dependencies_list}], link_args : '${linker_args}', c_args : [${macros}], install : true)

From 384aa9640c51d4ddf23b195e389eee442eded62b Mon Sep 17 00:00:00 2001
From: Rohit Goswami <rog32@hi.is>
Date: Fri, 25 Aug 2023 00:49:08 +0000
Subject: [PATCH 05/37] MAINT: Trim backend.py down to f2py2e flags

---
 numpy/f2py/backends/backend.py | 133 ++++++---------------------------
 1 file changed, 23 insertions(+), 110 deletions(-)

diff --git a/numpy/f2py/backends/backend.py b/numpy/f2py/backends/backend.py
index 30f0046c9f3e..d86789d1915f 100644
--- a/numpy/f2py/backends/backend.py
+++ b/numpy/f2py/backends/backend.py
@@ -1,125 +1,38 @@
 from __future__ import annotations
 
-from pathlib import Path
 from abc import ABC, abstractmethod
 
-import numpy
-import numpy.f2py as f2py
-
 
 class Backend(ABC):
-    """
-    Superclass for backend compilation plugins to extend.
-
-    """
-
     def __init__(
         self,
-        module_name,
-        fortran_compiler: str,
-        c_compiler: str,
-        f77exec: Path,
-        f90exec: Path,
-        f77_flags: list[str],
-        f90_flags: list[str],
-        include_paths: list[Path],
-        include_dirs: list[Path],
-        external_resources: list[str],
-        linker_libpath: list[Path],
-        linker_libname: list[str],
-        define_macros: list[tuple[str, str]],
-        undef_macros: list[str],
-        debug: bool,
-        opt_flags: list[str],
-        arch_flags: list[str],
-        no_opt: bool,
-        no_arch: bool,
-    ) -> None:
-        """
-        The class is initialized with f2py compile options.
-        The parameters are mappings of f2py compilation flags.
-
-        Parameters
-        ----------
-        module_name : str
-                The name of the module to be compiled. (-m)
-        fortran_compiler : str
-                Name of the Fortran compiler to use. (--fcompiler)
-        c_compiler : str
-                Name of the C compiler to use. (--ccompiler)
-        f77exec : Pathlike
-                Path to the fortran compiler for Fortran 77 files (--f77exec)
-        f90exec : Pathlike
-                Path to the fortran compiler for Fortran 90 and above files (--f90exec)
-        f77_flags : list
-                List of flags to pass to the fortran compiler for Fortran 77 files (--f77flags)
-        f90_flags : list
-                List of flags to pass to the fortran compiler for Fortran 90 and above files (--f90flags)
-        include_paths : list
-                Search include files from given directories (--include-paths)
-        include_dirs : list
-                Append directory <dir> to the list of directories searched for include files. (-I<dir>)
-        external_resources : list
-                Link the extension module with <resource> (--link-<resource>)
-        linker_libname : list
-                Use the library when linking. (-l<libname>)
-        define_macros : list
-                Define <macro> to <value> if present else define <macro> to true (-D)
-        undef_macros : list
-                Undefine <macro> (-U)
-        linker_libpath : list
-                Add directory to the list of directories to be searched for `-l`. (-L)
-        opt_flags : list
-                Optimization flags to pass to the compiler. (--opt)
-        arch_flags : list
-                Architectire specific flags to pass to the compiler (--arch)
-        no_opt : bool
-                Disable optimization. (--no-opt)
-        no_arch : bool
-                Disable architecture specific optimizations. (--no-arch)
-        debug : bool
-                Enable debugging. (--debug)
-
-        """
-        self.module_name = module_name
-        self.fortran_compiler = fortran_compiler
-        self.c_compiler = c_compiler
-        self.f77exec = f77exec
-        self.f90exec = f90exec
-        self.f77_flags = f77_flags
-        self.f90_flags = f90_flags
-        self.include_paths = include_paths
+        modulename,
+        include_dirs,
+        library_dirs,
+        libraries,
+        define_macros,
+        undef_macros,
+        f2py_flags,
+        sysinfo_flags,
+        fc_flags,
+        flib_flags,
+        setup_flags,
+        remove_build_dir,
+    ):
+        self.modulename = modulename
         self.include_dirs = include_dirs
-        self.external_resources = external_resources
-        self.linker_libpath = linker_libpath
-        self.linker_libname = linker_libname
+        self.library_dirs = library_dirs
+        self.libraries = libraries
         self.define_macros = define_macros
         self.undef_macros = undef_macros
-        self.debug = debug
-        self.opt_flags = opt_flags
-        self.arch_flags = arch_flags
-        self.no_opt = no_opt
-        self.no_arch = no_arch
-
-    def numpy_install_path(self) -> Path:
-        """
-        Returns the install path for numpy.
-        """
-        return Path(numpy.__file__).parent
-
-    def numpy_get_include(self) -> Path:
-        """
-        Returns the include paths for numpy.
-        """
-        return Path(numpy.get_include())
-
-    def f2py_get_include(self) -> Path:
-        """
-        Returns the include paths for f2py.
-        """
-        return Path(f2py.get_include())
+        self.f2py_flags = f2py_flags
+        self.sysinfo_flags = sysinfo_flags
+        self.fc_flags = fc_flags
+        self.flib_flags = flib_flags
+        self.setup_flags = setup_flags
+        self.remove_build_dir = remove_build_dir
 
     @abstractmethod
-    def compile(self, fortran_sources: Path, c_wrapper: Path, build_dir: Path) -> None:
+    def compile(self, sources, extra_objects, build_dir) -> None:
         """Compile the wrapper."""
         pass

From 26b224f49e4bab8057196162c70ef7a18d5d53e3 Mon Sep 17 00:00:00 2001
From: Rohit Goswami <rog32@hi.is>
Date: Fri, 25 Aug 2023 00:49:45 +0000
Subject: [PATCH 06/37] ENH: Add a factory function for backends

---
 numpy/f2py/backends/__init__.py | 13 ++++++++++---
 1 file changed, 10 insertions(+), 3 deletions(-)

diff --git a/numpy/f2py/backends/__init__.py b/numpy/f2py/backends/__init__.py
index 7c93fa16a715..cd3a6a93f002 100644
--- a/numpy/f2py/backends/__init__.py
+++ b/numpy/f2py/backends/__init__.py
@@ -1,4 +1,11 @@
-from .backend import Backend
-from .meson_backend import MesonBackend
+def get_backend(name):
+    if name == "meson":
+        from .meson_backend import MesonBackend
 
-backends = {"meson": MesonBackend}
+        return MesonBackend
+    elif name == "distutils":
+        from .distutils_backend import DistutilsBackend
+
+        return DistutilsBackend
+    else:
+        raise ValueError(f"Unknown backend: {name}")

From 3a5c43d2dc15ab482f438e56c72423a164cf5923 Mon Sep 17 00:00:00 2001
From: Rohit Goswami <rog32@hi.is>
Date: Fri, 25 Aug 2023 00:50:00 +0000
Subject: [PATCH 07/37] ENH: Add a distutils backend

---
 numpy/f2py/backends/distutils_backend.py | 71 ++++++++++++++++++++++++
 1 file changed, 71 insertions(+)
 create mode 100644 numpy/f2py/backends/distutils_backend.py

diff --git a/numpy/f2py/backends/distutils_backend.py b/numpy/f2py/backends/distutils_backend.py
new file mode 100644
index 000000000000..83bd8558e5db
--- /dev/null
+++ b/numpy/f2py/backends/distutils_backend.py
@@ -0,0 +1,71 @@
+from numpy.f2py.backends.backend import Backend
+
+from numpy.distutils.core import setup, Extension
+from numpy.distutils.system_info import get_info
+from numpy.distutils.misc_util import dict_append
+import os
+import sys
+import shutil
+import warnings
+
+
+class DistutilsBackend(Backend):
+    def __init__(sef, *args, **kwargs):
+        warnings.warn(
+            "distutils has been deprecated since NumPy 2.16."
+            "Use the MesonBackend instead, or generate wrappers"
+            "without -c and use a custom build script",
+            np.VisibleDeprecationWarning, stacklevel=2)
+        super().__init__(*args, **kwargs)
+
+    def compile(self, sources, extra_objects, build_dir):
+        num_info = {}
+        if num_info:
+            self.include_dirs.extend(num_info.get("include_dirs", []))
+        ext_args = {
+            "name": self.modulename,
+            "sources": sources,
+            "include_dirs": self.include_dirs,
+            "library_dirs": self.library_dirs,
+            "libraries": self.libraries,
+            "define_macros": self.define_macros,
+            "undef_macros": self.undef_macros,
+            "extra_objects": extra_objects,
+            "f2py_options": self.f2py_flags,
+        }
+
+        if self.sysinfo_flags:
+            for n in self.sysinfo_flags:
+                i = get_info(n)
+                if not i:
+                    print(
+                        f"No {repr(n)} resources found in system (try `f2py --help-link`)"
+                    )
+                dict_append(ext_args, **i)
+
+        ext = Extension(**ext_args)
+
+        sys.argv = [sys.argv[0]] + self.setup_flags
+        sys.argv.extend(
+            [
+                "build",
+                "--build-temp",
+                build_dir,
+                "--build-base",
+                build_dir,
+                "--build-platlib",
+                ".",
+                "--disable-optimization",
+            ]
+        )
+
+        if self.fc_flags:
+            sys.argv.extend(["config_fc"] + self.fc_flags)
+        if self.flib_flags:
+            sys.argv.extend(["build_ext"] + self.flib_flags)
+
+        setup(ext_modules=[ext])
+
+        if self.remove_build_dir and os.path.exists(build_dir):
+            print(f"Removing build directory {build_dir}")
+            shutil.rmtree(build_dir)

From d03d28de31a1f82df2fc2a75702b7e4838d2c0f7 Mon Sep 17 00:00:00 2001
From: Rohit Goswami <rog32@hi.is>
Date: Fri, 25 Aug 2023 00:50:30 +0000
Subject: [PATCH 08/37] ENH: Handle --backends in f2py

Defaults to distutils for now
---
 numpy/f2py/f2py2e.py | 54 ++++++++++++--------------------------------
 1 file changed, 15 insertions(+), 39 deletions(-)

diff --git a/numpy/f2py/f2py2e.py b/numpy/f2py/f2py2e.py
index 10508488dc04..0b72e5d52058 100755
--- a/numpy/f2py/f2py2e.py
+++ b/numpy/f2py/f2py2e.py
@@ -28,6 +28,7 @@
 from . import f90mod_rules
 from . import __version__
 from . import capi_maps
+from . import backends
 
 f2py_version = __version__.version
 numpy_version = __version__.version
@@ -588,6 +589,15 @@ def run_compile():
     if '--quiet' in f2py_flags:
         setup_flags.append('--quiet')
 
+    # Check for and remove --backend first
+    if '--backend' in sys.argv:
+        backend_index = sys.argv.index('--backend')
+        backend_key = sys.argv.pop(backend_index + 1)
+        sys.argv.pop(backend_index)
+    else:
+        backend_key = 'distutils'
+    build_backend = backends.get_backend(backend_key)
+
     modulename = 'untitled'
     sources = sys.argv[1:]
 
@@ -633,46 +643,12 @@ def run_compile():
     if num_info:
         include_dirs.extend(num_info.get('include_dirs', []))
 
-    from numpy.distutils.core import setup, Extension
-    ext_args = {'name': modulename, 'sources': sources,
-                'include_dirs': include_dirs,
-                'library_dirs': library_dirs,
-                'libraries': libraries,
-                'define_macros': define_macros,
-                'undef_macros': undef_macros,
-                'extra_objects': extra_objects,
-                'f2py_options': f2py_flags,
-                }
-
-    if sysinfo_flags:
-        from numpy.distutils.misc_util import dict_append
-        for n in sysinfo_flags:
-            i = get_info(n)
-            if not i:
-                outmess('No %s resources found in system'
-                        ' (try `f2py --help-link`)\n' % (repr(n)))
-            dict_append(ext_args, **i)
-
-    ext = Extension(**ext_args)
-    sys.argv = [sys.argv[0]] + setup_flags
-    sys.argv.extend(['build',
-                     '--build-temp', build_dir,
-                     '--build-base', build_dir,
-                     '--build-platlib', '.',
-                     # disable CCompilerOpt
-                     '--disable-optimization'])
-    if fc_flags:
-        sys.argv.extend(['config_fc'] + fc_flags)
-    if flib_flags:
-        sys.argv.extend(['build_ext'] + flib_flags)
-
-    setup(ext_modules=[ext])
-
-    if remove_build_dir and os.path.exists(build_dir):
-        import shutil
-        outmess('Removing build directory %s\n' % (build_dir))
-        shutil.rmtree(build_dir)
+    # Now use the builder
+    builder = build_backend(modulename, include_dirs, library_dirs, libraries,
+                            define_macros, undef_macros, f2py_flags,
+                            sysinfo_flags, fc_flags, flib_flags, setup_flags, remove_build_dir)
 
+    builder.compile(sources, extra_objects, build_dir)
 
 def main():
     if '--help-link' in sys.argv[1:]:

From 1d279bc106ed6b9d9c3bc1e5980649404b383f1c Mon Sep 17 00:00:00 2001
From: Rohit Goswami <rog32@hi.is>
Date: Fri, 25 Aug 2023 00:50:55 +0000
Subject: [PATCH 09/37] DOC: Add some minor comments in f2py2e

---
 numpy/f2py/f2py2e.py | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/numpy/f2py/f2py2e.py b/numpy/f2py/f2py2e.py
index 0b72e5d52058..60fc2913dacd 100755
--- a/numpy/f2py/f2py2e.py
+++ b/numpy/f2py/f2py2e.py
@@ -252,6 +252,8 @@ def scaninputline(inputline):
                 'f2py option --include_paths is deprecated, use --include-paths instead.\n')
             f7 = 1
         elif l[:15] in '--include-paths':
+            # Similar to using -I with -c, however this is
+            # also used during generation of wrappers
             f7 = 1
         elif l == '--skip-empty-wrappers':
             emptygen = False
@@ -675,6 +677,12 @@ def main():
         pass
 
     if '-c' in sys.argv[1:]:
+        import warnings
+        warnings.warn('Using f2py to compile code without generating files '
+                      'first was largely handled by distutils which has been removed in Python 3.12.'
+                      'The meson replacement is a work in progress, consider running without -c.'
+                      'Recall that the build can be customized with --build-dir',
+                      stacklevel=2)
         run_compile()
     else:
         run_main(sys.argv[1:])

From 0f0e3ac4cf8e84de4321833e0d1b9df506cfe264 Mon Sep 17 00:00:00 2001
From: Rohit Goswami <rog32@hi.is>
Date: Fri, 25 Aug 2023 01:05:19 +0000
Subject: [PATCH 10/37] MAINT: Refactor and rework meson.build.src

---
 numpy/f2py/backends/src/meson.build.src | 38 +++++++++++++++++++------
 1 file changed, 29 insertions(+), 9 deletions(-)

diff --git a/numpy/f2py/backends/src/meson.build.src b/numpy/f2py/backends/src/meson.build.src
index 8d2ce5fde994..b1f87818ed7d 100644
--- a/numpy/f2py/backends/src/meson.build.src
+++ b/numpy/f2py/backends/src/meson.build.src
@@ -1,22 +1,42 @@
 project('${modulename}', 'c',
   version : '0.1',
+  meson_version: '>= 1.1.0',
   default_options : ['warning_level=2'])
 
 add_languages('fortran')
 
-add_global_arguments(${c_global_args}, language: 'c')
-add_global_arguments(${fortran_global_args}, language: 'fortran')
+add_project_arguments(${c_global_args}, language: 'c')
+add_project_arguments(${fortran_global_args}, language: 'fortran')
 
 py_mod = import('python')
-py3 = py_mod.find_installation('python3')
-py3_dep = py3.dependency()
-message(py3.path())
-message(py3.get_install_dir())
+py = py_mod.find_installation(pure: false)
+py_dep = py.dependency()
 
-incdir_numpy = '${numpy_get_include}'
+incdir_numpy = run_command(py,
+  ['-c', 'import os; os.chdir(".."); import numpy; print(numpy.get_include())'],
+  check : true
+).stdout().strip()
 
-incdir_f2py = '${f2py_get_include}'
+incdir_f2py = run_command(py,
+    ['-c', 'import os; os.chdir(".."); import numpy.f2py; print(numpy.f2py.get_include())'],
+    check : true
+).stdout().strip()
+
+inc_np = include_directories(incdir_numpy)
+np_dep = declare_dependency(include_directories: inc_np)
+
+incdir_f2py = incdir_numpy / '..' / '..' / 'f2py' / 'src'
+inc_f2py = include_directories(incdir_f2py)
+fortranobject_c = incdir_f2py / 'fortranobject.c'
 
 inc_np = include_directories(incdir_numpy, incdir_f2py)
 
-py3.extension_module('${modulename}', ${wrappers}, ${source_list}, incdir_f2py+'/fortranobject.c', include_directories: [inc_np, ${include_directories_list}], dependencies : [py3_dep, ${dependencies_list}], link_args : '${linker_args}', c_args : [${macros}], install : true)
+py3.extension_module('${modulename}',
+                      ${wrappers},
+                      ${source_list},
+                      fortranobject_c,
+                      include_directories: [inc_np, ${include_directories_list}],
+                      dependencies : [py3_dep, ${dependencies_list}],
+                      link_args : '${linker_args}',
+                      c_args : [${macros}],
+                      install : true)

From 323fa5b64297ecde64f23c82b287a63717bdc9ca Mon Sep 17 00:00:00 2001
From: Rohit Goswami <rog32@hi.is>
Date: Fri, 25 Aug 2023 01:05:51 +0000
Subject: [PATCH 11/37] MAINT: Add objects

---
 numpy/f2py/backends/src/meson.build.src | 1 +
 1 file changed, 1 insertion(+)

diff --git a/numpy/f2py/backends/src/meson.build.src b/numpy/f2py/backends/src/meson.build.src
index b1f87818ed7d..d64146b3c040 100644
--- a/numpy/f2py/backends/src/meson.build.src
+++ b/numpy/f2py/backends/src/meson.build.src
@@ -37,6 +37,7 @@ py3.extension_module('${modulename}',
                       fortranobject_c,
                       include_directories: [inc_np, ${include_directories_list}],
                       dependencies : [py3_dep, ${dependencies_list}],
+                      objects : ${objects_list},
                       link_args : '${linker_args}',
                       c_args : [${macros}],
                       install : true)

From 8d4368b712e860b9d9ab1019e7e3bdb8de73bee4 Mon Sep 17 00:00:00 2001
From: Rohit Goswami <rog32@hi.is>
Date: Fri, 25 Aug 2023 01:12:42 +0000
Subject: [PATCH 12/37] MAINT: Cleanup distutils backend

---
 numpy/f2py/backends/distutils_backend.py | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/numpy/f2py/backends/distutils_backend.py b/numpy/f2py/backends/distutils_backend.py
index 83bd8558e5db..263c59223cf9 100644
--- a/numpy/f2py/backends/distutils_backend.py
+++ b/numpy/f2py/backends/distutils_backend.py
@@ -3,6 +3,7 @@
 from numpy.distutils.core import setup, Extension
 from numpy.distutils.system_info import get_info
 from numpy.distutils.misc_util import dict_append
+from numpy.exceptions import VisibleDeprecationWarning
 import os
 import sys
 import shutil
@@ -15,7 +16,9 @@ def __init__(sef, *args, **kwargs):
             "distutils has been deprecated since NumPy 2.16."
             "Use the MesonBackend instead, or generate wrappers"
             "without -c and use a custom build script",
-            np.VisibleDeprecationWarning, stacklevel=2)
+            VisibleDeprecationWarning,
+            stacklevel=2,
+        )
         super().__init__(*args, **kwargs)
 
     def compile(self, sources, extra_objects, build_dir):

From 7bd8c34bf3192f31fec8ded88b94529c66903e97 Mon Sep 17 00:00:00 2001
From: Rohit Goswami <rog32@hi.is>
Date: Fri, 25 Aug 2023 01:45:54 +0000
Subject: [PATCH 13/37] MAINT: Refactor to add everything back to backend

Necessary for the meson.build for now. Refactors / cleanup needs better
argument handling in f2py2e
---
 numpy/f2py/backends/backend.py           |  8 +++++++-
 numpy/f2py/backends/distutils_backend.py | 17 +++++++++--------
 numpy/f2py/f2py2e.py                     | 24 +++++++++++++++++++-----
 3 files changed, 35 insertions(+), 14 deletions(-)

diff --git a/numpy/f2py/backends/backend.py b/numpy/f2py/backends/backend.py
index d86789d1915f..9fea9d243137 100644
--- a/numpy/f2py/backends/backend.py
+++ b/numpy/f2py/backends/backend.py
@@ -7,6 +7,9 @@ class Backend(ABC):
     def __init__(
         self,
         modulename,
+        sources,
+        extra_objects,
+        build_dir,
         include_dirs,
         library_dirs,
         libraries,
@@ -20,6 +23,9 @@ def __init__(
         remove_build_dir,
     ):
         self.modulename = modulename
+        self.sources = sources
+        self.extra_objects = extra_objects
+        self.build_dir = build_dir
         self.include_dirs = include_dirs
         self.library_dirs = library_dirs
         self.libraries = libraries
@@ -33,6 +39,6 @@ def __init__(
         self.remove_build_dir = remove_build_dir
 
     @abstractmethod
-    def compile(self, sources, extra_objects, build_dir) -> None:
+    def compile(self) -> None:
         """Compile the wrapper."""
         pass
diff --git a/numpy/f2py/backends/distutils_backend.py b/numpy/f2py/backends/distutils_backend.py
index 263c59223cf9..8f79682f2d34 100644
--- a/numpy/f2py/backends/distutils_backend.py
+++ b/numpy/f2py/backends/distutils_backend.py
@@ -21,19 +21,20 @@ def __init__(sef, *args, **kwargs):
         )
         super().__init__(*args, **kwargs)
 
-    def compile(self, sources, extra_objects, build_dir):
+    def compile(self):
         num_info = {}
         if num_info:
             self.include_dirs.extend(num_info.get("include_dirs", []))
         ext_args = {
             "name": self.modulename,
-            "sources": sources,
+            "sources": self.sources,
             "include_dirs": self.include_dirs,
             "library_dirs": self.library_dirs,
             "libraries": self.libraries,
             "define_macros": self.define_macros,
             "undef_macros": self.undef_macros,
-            "extra_objects": extra_objects,
+            # TODO: Handle extra_objects in meson
+            "extra_objects": self.extra_objects,
             "f2py_options": self.f2py_flags,
         }
 
@@ -53,9 +54,9 @@ def compile(self, sources, extra_objects, build_dir):
             [
                 "build",
                 "--build-temp",
-                build_dir,
+                self.build_dir,
                 "--build-base",
-                build_dir,
+                self.build_dir,
                 "--build-platlib",
                 ".",
                 "--disable-optimization",
@@ -69,6 +70,6 @@ def compile(self, sources, extra_objects, build_dir):
 
         setup(ext_modules=[ext])
 
-        if self.remove_build_dir and os.path.exists(build_dir):
-            print(f"Removing build directory {build_dir}")
-            shutil.rmtree(build_dir)
+        if self.remove_build_dir and os.path.exists(self.build_dir):
+            print(f"Removing build directory {self.build_dir}")
+            shutil.rmtree(self.build_dir)
diff --git a/numpy/f2py/f2py2e.py b/numpy/f2py/f2py2e.py
index 60fc2913dacd..0cb59e279e85 100755
--- a/numpy/f2py/f2py2e.py
+++ b/numpy/f2py/f2py2e.py
@@ -646,11 +646,25 @@ def run_compile():
         include_dirs.extend(num_info.get('include_dirs', []))
 
     # Now use the builder
-    builder = build_backend(modulename, include_dirs, library_dirs, libraries,
-                            define_macros, undef_macros, f2py_flags,
-                            sysinfo_flags, fc_flags, flib_flags, setup_flags, remove_build_dir)
-
-    builder.compile(sources, extra_objects, build_dir)
+    builder = build_backend(
+        modulename,
+        sources,
+        extra_objects,
+        build_dir,
+        include_dirs,
+        library_dirs,
+        libraries,
+        define_macros,
+        undef_macros,
+        f2py_flags,
+        sysinfo_flags,
+        fc_flags,
+        flib_flags,
+        setup_flags,
+        remove_build_dir,
+    )
+
+    builder.compile()
 
 def main():
     if '--help-link' in sys.argv[1:]:

From d7a1ea98b405a1fca4e7d9ad8e7096c35599563a Mon Sep 17 00:00:00 2001
From: Rohit Goswami <rog32@hi.is>
Date: Fri, 25 Aug 2023 03:39:11 +0000
Subject: [PATCH 14/37] MAINT: Fix overly long line

---
 numpy/f2py/backends/distutils_backend.py | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/numpy/f2py/backends/distutils_backend.py b/numpy/f2py/backends/distutils_backend.py
index 8f79682f2d34..4e5aac72f398 100644
--- a/numpy/f2py/backends/distutils_backend.py
+++ b/numpy/f2py/backends/distutils_backend.py
@@ -43,7 +43,8 @@ def compile(self):
                 i = get_info(n)
                 if not i:
                     print(
-                        f"No {repr(n)} resources found in system (try `f2py --help-link`)"
+                        f"No {repr(n)} resources found"
+                        "in system (try `f2py --help-link`)"
                     )
                 dict_append(ext_args, **i)
 

From a95e71a7a9f3d71dab756e9de55b44344443d15d Mon Sep 17 00:00:00 2001
From: Rohit Goswami <rog32@hi.is>
Date: Fri, 25 Aug 2023 03:39:34 +0000
Subject: [PATCH 15/37] BUG: Construct wrappers for meson backend

---
 numpy/f2py/f2py2e.py | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/numpy/f2py/f2py2e.py b/numpy/f2py/f2py2e.py
index 0cb59e279e85..a78a6be6123c 100755
--- a/numpy/f2py/f2py2e.py
+++ b/numpy/f2py/f2py2e.py
@@ -639,11 +639,11 @@ def run_compile():
         else:
             print('Invalid use of -D:', name_value)
 
-    from numpy.distutils.system_info import get_info
-
-    num_info = {}
-    if num_info:
-        include_dirs.extend(num_info.get('include_dirs', []))
+    # Construct wrappers / signatures / things
+    if backend_key == 'meson':
+        outmess('Using meson backend\nWill pass --lower to f2py\nSee https://numpy.org/doc/stable/f2py/buildtools/meson.html')
+        f2py_flags.append('--lower')
+    run_main(f" {' '.join(f2py_flags)} -m {modulename} {' '.join(sources)}".split())
 
     # Now use the builder
     builder = build_backend(

From 06210325050831ee60c7c96c8a8ee866b7533385 Mon Sep 17 00:00:00 2001
From: Rohit Goswami <rog32@hi.is>
Date: Fri, 25 Aug 2023 03:40:14 +0000
Subject: [PATCH 16/37] MAINT: Rework, simplify template massively

---
 numpy/f2py/backends/src/meson.build.src | 29 +++++++++----------------
 1 file changed, 10 insertions(+), 19 deletions(-)

diff --git a/numpy/f2py/backends/src/meson.build.src b/numpy/f2py/backends/src/meson.build.src
index d64146b3c040..84b8f169dbb6 100644
--- a/numpy/f2py/backends/src/meson.build.src
+++ b/numpy/f2py/backends/src/meson.build.src
@@ -1,12 +1,8 @@
-project('${modulename}', 'c',
-  version : '0.1',
-  meson_version: '>= 1.1.0',
-  default_options : ['warning_level=2'])
-
-add_languages('fortran')
-
-add_project_arguments(${c_global_args}, language: 'c')
-add_project_arguments(${fortran_global_args}, language: 'fortran')
+project('${modulename}',
+        ['c', 'fortran'],
+        version : '0.1',
+        meson_version: '>= 1.1.0',
+        default_options : ['warning_level=2'])
 
 py_mod = import('python')
 py = py_mod.find_installation(pure: false)
@@ -31,13 +27,8 @@ fortranobject_c = incdir_f2py / 'fortranobject.c'
 
 inc_np = include_directories(incdir_numpy, incdir_f2py)
 
-py3.extension_module('${modulename}',
-                      ${wrappers},
-                      ${source_list},
-                      fortranobject_c,
-                      include_directories: [inc_np, ${include_directories_list}],
-                      dependencies : [py3_dep, ${dependencies_list}],
-                      objects : ${objects_list},
-                      link_args : '${linker_args}',
-                      c_args : [${macros}],
-                      install : true)
+py.extension_module('${modulename}',
+                     [${source_list}, fortranobject_c],
+                     include_directories: [inc_np],
+                     dependencies : [py_dep],
+                     install : true)

From 677e42a50efe28cf6b26f4e2b6127ddb4deb3df7 Mon Sep 17 00:00:00 2001
From: Rohit Goswami <rog32@hi.is>
Date: Fri, 25 Aug 2023 03:40:26 +0000
Subject: [PATCH 17/37] ENH: Truncate meson.build to skeleton only

---
 numpy/f2py/backends/meson_backend.py | 293 ++++++---------------------
 1 file changed, 61 insertions(+), 232 deletions(-)

diff --git a/numpy/f2py/backends/meson_backend.py b/numpy/f2py/backends/meson_backend.py
index df0d1b4fdb8b..49820f036e8f 100644
--- a/numpy/f2py/backends/meson_backend.py
+++ b/numpy/f2py/backends/meson_backend.py
@@ -1,6 +1,5 @@
 from __future__ import annotations
 
-import os
 import errno
 import shutil
 import subprocess
@@ -9,228 +8,71 @@
 from .backend import Backend
 from string import Template
 
+import warnings
+
 
 class MesonTemplate:
     """Template meson build file generation class."""
 
     def __init__(
         self,
-        module_name: str,
-        numpy_install_path,
-        numpy_get_include: Path,
-        f2py_get_include: Path,
-        wrappers: list[Path],
-        fortran_sources: list[Path],
-        dependencies: list[str],
-        include_path: list[Path],
-        optimization_flags: list[str],
-        architecture_flags: list[str],
-        f77_flags: list[str],
-        f90_flags: list[str],
-        linker_libpath: list[Path],
-        linker_libname: list[str],
-        define_macros: list[tuple[str, str]],
-        undef_macros: list[str],
+        modulename: str,
+        sources: list[Path],
+        object_files: list[Path],
+        linker_args: list[str],
+        c_args: list[str],
     ):
-        self.module_name = module_name
-        self.numpy_install_path = numpy_install_path
+        self.modulename = modulename
         self.build_template_path = (
-            numpy_install_path / "f2py" / "backends" / "src" / "meson.build.src"
+            Path(__file__).parent.absolute() / "src" / "meson.build.src"
         )
-        self.sources = fortran_sources
-        self.numpy_get_include = numpy_get_include
-        self.f2py_get_include = f2py_get_include
-        self.wrappers = wrappers
-        self.dependencies = dependencies
-        self.include_directories = include_path
+        self.sources = sources
         self.substitutions = {}
-        self.optimization_flags = optimization_flags
-        self.architecture_flags = architecture_flags
-        self.fortran_flags = f77_flags + f90_flags
-        self.linker_libpath = linker_libpath
-        self.linker_libname = linker_libname
-        self.define_macros = define_macros
-        self.undef_macros = undef_macros
+        self.objects = object_files
         self.pipeline = [
             self.initialize_template,
-            self.global_flags_substitution,
             self.sources_substitution,
-            self.dependencies_substitution,
-            self.include_directories_subtitution,
-            self.linker_substitution,
-            self.macros_substitution,
         ]
 
-    @property
     def meson_build_template(self) -> str:
         if not self.build_template_path.is_file():
             raise FileNotFoundError(
                 errno.ENOENT,
-                f"Meson build template {self.build_template_path.absolute()} does not exist.",
+                "Meson build template"
+                f" {self.build_template_path.absolute()}"
+                " does not exist.",
             )
         return self.build_template_path.read_text()
 
     def initialize_template(self) -> None:
-        """Initialize with module name and external NumPy and F2PY C libraries."""
-        self.substitutions["modulename"] = self.module_name
-        self.substitutions["numpy_get_include"] = self.numpy_get_include.absolute()
-        self.substitutions["f2py_get_include"] = self.f2py_get_include.absolute()
+        """Initialize with module name."""
+        self.substitutions["modulename"] = self.modulename
 
     def sources_substitution(self) -> None:
-        self.substitutions["source_list"] = ",".join(
-            ["'" + str(source.absolute()) + "'" for source in self.sources]
-        )
-        self.substitutions["wrappers"] = ",".join(
-            ["'" + str(wrapper.absolute()) + "'" for wrapper in self.wrappers]
-        )
-
-    def dependencies_substitution(self) -> None:
-        self.substitutions["dependencies_list"] = ", ".join(
-            [f"dependency('{dependecy}')" for dependecy in self.dependencies]
-        )
-
-    def include_directories_subtitution(self) -> None:
-        self.substitutions["include_directories_list"] = ", ".join(
-            [
-                f"include_directories('{include_directory}')"
-                for include_directory in self.include_directories
-            ]
-        )
-
-    def global_flags_substitution(self) -> None:
-        fortran_compiler_flags = (
-            self.fortran_flags + self.optimization_flags + self.architecture_flags
+        self.substitutions["source_list"] = ", ".join(
+            [f"'{source}'" for source in self.sources]
         )
-        c_compiler_flags = self.optimization_flags + self.architecture_flags
-        self.substitutions["fortran_global_args"] = fortran_compiler_flags
-        self.substitutions["c_global_args"] = c_compiler_flags
-
-    def macros_substitution(self) -> None:
-        self.substitutions["macros"] = ""
-        if self.define_macros:
-            self.substitutions["macros"] = ",".join(
-                f"'-D{macro[0]}={macro[1]}'" if macro[1] else f"-D{macro[0]}"
-                for macro in self.define_macros
-            )
-        if self.undef_macros:
-            self.substitutions["macros"] += "," + ",".join(
-                f"'-U{macro}'" for macro in self.undef_macros
-            )
 
-    def linker_substitution(self) -> None:
-        self.substitutions["linker_args"] = ""
-        if self.linker_libpath:
-            linker_libpath_subs = ",".join(
-                f"-L{libpath}" for libpath in self.linker_libpath
-            )
-            self.substitutions["linker_args"] += linker_libpath_subs
-        if self.linker_libname:
-            linker_libname_subs = ",".join(
-                f"-l{libname}" for libname in self.linker_libname
-            )
-            self.substitutions["linker_args"] += f",{linker_libname_subs}"
-
-    def generate_meson_build(self) -> str:
+    def generate_meson_build(self):
         for node in self.pipeline:
             node()
-        template = Template(self.meson_build_template)
+        template = Template(self.meson_build_template())
         return template.substitute(self.substitutions)
 
 
 class MesonBackend(Backend):
-    def __init__(
-        self,
-        module_name: str = "untitled",
-        fortran_compiler: str = None,
-        c_compiler: str = None,
-        f77exec: Path = None,
-        f90exec: Path = None,
-        f77_flags: list[str] = None,
-        f90_flags: list[str] = None,
-        include_paths: list[Path] = None,
-        include_dirs: list[Path] = None,
-        external_resources: list[str] = None,
-        linker_libpath: list[Path] = None,
-        linker_libname: list[str] = None,
-        define_macros: list[tuple[str, str]] = None,
-        undef_macros: list[str] = None,
-        debug: bool = False,
-        opt_flags: list[str] = None,
-        arch_flags: list[str] = None,
-        no_opt: bool = False,
-        no_arch: bool = False,
-    ) -> None:
-        self.meson_build_dir = "builddir"
-        if f77_flags is None:
-            f77_flags = []
-        if include_paths is None:
-            include_paths = []
-        if include_dirs is None:
-            include_dirs = []
-        if external_resources is None:
-            external_resources = []
-        if linker_libpath is None:
-            linker_libpath = []
-        if linker_libname is None:
-            linker_libname = []
-        if define_macros is None:
-            define_macros = []
-        if undef_macros is None:
-            undef_macros = []
-        if f77_flags is None:
-            f77_flags = []
-        if f90_flags is None:
-            f90_flags = []
-        if opt_flags is None:
-            opt_flags = []
-        if arch_flags is None:
-            arch_flags = []
-        super().__init__(
-            module_name,
-            fortran_compiler,
-            c_compiler,
-            f77exec,
-            f90exec,
-            f77_flags,
-            f90_flags,
-            include_paths,
-            include_dirs,
-            external_resources,
-            linker_libpath,
-            linker_libname,
-            define_macros,
-            undef_macros,
-            debug,
-            opt_flags,
-            arch_flags,
-            no_opt,
-            no_arch,
+    def __init__(self, *args, **kwargs):
+        warnings.warn(
+            "The MesonBackend is experimental and may change in the future."
+            "--build-dir should be used to customize the generated skeleton.",
+            stacklevel=2,
         )
-
-        self.wrappers: list[Path] = []
-        self.fortran_sources: list[Path] = []
-        self.template = Template(self.fortran_sources)
-
-    def _get_optimization_level(self):
-        if self.no_arch and not self.no_opt:
-            return 2
-        elif self.no_opt:
-            return 0
-        return 3
-
-    def _set_environment_variables(self) -> None:
-        if self.fortran_compiler:
-            os.putenv("FC", self.fortran_compiler)
-        elif self.f77exec:
-            os.putenv("FC", self.f77exec)
-        elif self.f90exec:
-            os.putenv("FC", self.f90exec)
-        if self.c_compiler:
-            os.putenv("CC", self.c_compiler)
+        super().__init__(*args, **kwargs)
+        self.meson_build_dir = "bbdir"
 
     def _move_exec_to_root(self, build_dir: Path):
-        walk_dir = build_dir / self.meson_build_dir
-        path_objects = walk_dir.glob(f"{self.module_name}*.so")
+        walk_dir = Path(build_dir) / self.meson_build_dir
+        path_objects = walk_dir.glob(f"{self.modulename}*.so")
         for path_object in path_objects:
             shutil.move(path_object, Path.cwd())
 
@@ -239,49 +81,24 @@ def _get_build_command(self):
             "meson",
             "setup",
             self.meson_build_dir,
-            "-Ddebug=true" if self.debug else "-Ddebug=false",
-            f"-Doptimization={str(self._get_optimization_level())}",
         ]
 
-    def load_wrapper(self, wrappers: list[Path]) -> None:
-        self.wrappers = wrappers
-
-    def load_sources(self, fortran_sources: list[Path]) -> None:
-        for fortran_source in fortran_sources:
-            fortran_source = Path(fortran_source)
-            if not fortran_source.is_file():
-                raise FileNotFoundError(
-                    errno.ENOENT, f"{fortran_source.absolute()} does not exist."
-                )
-            self.fortran_sources.append(fortran_source)
-
     def write_meson_build(self, build_dir: Path) -> None:
         """Writes the meson build file at specified location"""
         meson_template = MesonTemplate(
-            self.module_name,
-            super().numpy_install_path(),
-            self.numpy_get_include(),
-            self.f2py_get_include(),
-            self.wrappers,
-            self.fortran_sources,
-            self.external_resources,
-            self.include_paths + self.include_dirs,
-            optimization_flags=self.opt_flags,
-            architecture_flags=self.arch_flags,
-            f77_flags=self.f77_flags,
-            f90_flags=self.f90_flags,
-            linker_libpath=self.linker_libpath,
-            linker_libname=self.linker_libname,
-            define_macros=self.define_macros,
-            undef_macros=self.undef_macros,
+            self.modulename,
+            self.sources,
+            self.extra_objects,
+            self.flib_flags,
+            self.fc_flags,
         )
         src = meson_template.generate_meson_build()
-        meson_build_file = build_dir / "meson.build"
+        Path(build_dir).mkdir(parents=True, exist_ok=True)
+        meson_build_file = Path(build_dir) / "meson.build"
         meson_build_file.write_text(src)
         return meson_build_file
 
     def run_meson(self, build_dir: Path):
-        self._set_environment_variables()
         completed_process = subprocess.run(self._get_build_command(), cwd=build_dir)
         if completed_process.returncode != 0:
             raise subprocess.CalledProcessError(
@@ -295,16 +112,28 @@ def run_meson(self, build_dir: Path):
                 completed_process.returncode, completed_process.args
             )
 
-    def compile(
-        self,
-        f77_sources: list[Path],
-        f90_sources: list[Path],
-        object_files: list[Path],
-        wrappers: list[Path],
-        build_dir: Path,
-    ) -> None:
-        self.load_wrapper(wrappers)
-        self.load_sources(f77_sources + f90_sources + object_files)
-        self.write_meson_build(build_dir)
-        self.run_meson(build_dir)
-        self._move_exec_to_root(build_dir)
+    def compile(self) -> None:
+        self.sources = _prepare_sources(self.modulename, self.sources, self.build_dir)
+        self.write_meson_build(self.build_dir)
+        self.run_meson(self.build_dir)
+        self._move_exec_to_root(self.build_dir)
+
+
+def _prepare_sources(mname, sources, bdir):
+    extended_sources = sources.copy()
+    Path(bdir).mkdir(parents=True, exist_ok=True)
+    # Copy sources
+    for source in sources:
+        shutil.copy(source, bdir)
+    generated_sources = [
+        Path(f"{mname}module.c"),
+        Path(f"{mname}-f2pywrappers2.f90"),
+        Path(f"{mname}-f2pywrappers.f"),
+    ]
+    bdir = Path(bdir)
+    for generated_source in generated_sources:
+        if generated_source.exists():
+            shutil.copy(generated_source, bdir / generated_source.name)
+            extended_sources.append(bdir / generated_source.name)
+            generated_source.unlink()
+    return extended_sources

From 2517afeace4aea2070d858e9184f0d84eb644a50 Mon Sep 17 00:00:00 2001
From: Rohit Goswami <rog32@hi.is>
Date: Fri, 25 Aug 2023 03:58:10 +0000
Subject: [PATCH 18/37] MAINT: Minor backend housekeeping, name changes

---
 numpy/f2py/{backends => _backends}/__init__.py            | 8 +++-----
 numpy/f2py/{backends/backend.py => _backends/_backend.py} | 0
 .../distutils_backend.py => _backends/_distutils.py}      | 2 +-
 .../{backends/meson_backend.py => _backends/_meson.py}    | 4 ++--
 numpy/f2py/{backends => _backends}/src/meson.build.src    | 0
 numpy/f2py/f2py2e.py                                      | 4 ++--
 6 files changed, 8 insertions(+), 10 deletions(-)
 rename numpy/f2py/{backends => _backends}/__init__.py (57%)
 rename numpy/f2py/{backends/backend.py => _backends/_backend.py} (100%)
 rename numpy/f2py/{backends/distutils_backend.py => _backends/_distutils.py} (98%)
 rename numpy/f2py/{backends/meson_backend.py => _backends/_meson.py} (97%)
 rename numpy/f2py/{backends => _backends}/src/meson.build.src (100%)

diff --git a/numpy/f2py/backends/__init__.py b/numpy/f2py/_backends/__init__.py
similarity index 57%
rename from numpy/f2py/backends/__init__.py
rename to numpy/f2py/_backends/__init__.py
index cd3a6a93f002..e91393c14be3 100644
--- a/numpy/f2py/backends/__init__.py
+++ b/numpy/f2py/_backends/__init__.py
@@ -1,11 +1,9 @@
-def get_backend(name):
+def f2py_build_generator(name):
     if name == "meson":
-        from .meson_backend import MesonBackend
-
+        from ._meson import MesonBackend
         return MesonBackend
     elif name == "distutils":
-        from .distutils_backend import DistutilsBackend
-
+        from ._distutils import DistutilsBackend
         return DistutilsBackend
     else:
         raise ValueError(f"Unknown backend: {name}")
diff --git a/numpy/f2py/backends/backend.py b/numpy/f2py/_backends/_backend.py
similarity index 100%
rename from numpy/f2py/backends/backend.py
rename to numpy/f2py/_backends/_backend.py
diff --git a/numpy/f2py/backends/distutils_backend.py b/numpy/f2py/_backends/_distutils.py
similarity index 98%
rename from numpy/f2py/backends/distutils_backend.py
rename to numpy/f2py/_backends/_distutils.py
index 4e5aac72f398..efc7a98b7692 100644
--- a/numpy/f2py/backends/distutils_backend.py
+++ b/numpy/f2py/_backends/_distutils.py
@@ -1,4 +1,4 @@
-from numpy.f2py.backends.backend import Backend
+from ._backend import Backend
 
 from numpy.distutils.core import setup, Extension
 from numpy.distutils.system_info import get_info
diff --git a/numpy/f2py/backends/meson_backend.py b/numpy/f2py/_backends/_meson.py
similarity index 97%
rename from numpy/f2py/backends/meson_backend.py
rename to numpy/f2py/_backends/_meson.py
index 49820f036e8f..86e0a1a3943c 100644
--- a/numpy/f2py/backends/meson_backend.py
+++ b/numpy/f2py/_backends/_meson.py
@@ -5,7 +5,7 @@
 import subprocess
 from pathlib import Path
 
-from .backend import Backend
+from ._backend import Backend
 from string import Template
 
 import warnings
@@ -134,6 +134,6 @@ def _prepare_sources(mname, sources, bdir):
     for generated_source in generated_sources:
         if generated_source.exists():
             shutil.copy(generated_source, bdir / generated_source.name)
-            extended_sources.append(bdir / generated_source.name)
+            extended_sources.append(Path(bdir / generated_source.name).absolute())
             generated_source.unlink()
     return extended_sources
diff --git a/numpy/f2py/backends/src/meson.build.src b/numpy/f2py/_backends/src/meson.build.src
similarity index 100%
rename from numpy/f2py/backends/src/meson.build.src
rename to numpy/f2py/_backends/src/meson.build.src
diff --git a/numpy/f2py/f2py2e.py b/numpy/f2py/f2py2e.py
index a78a6be6123c..0a6d164b4890 100755
--- a/numpy/f2py/f2py2e.py
+++ b/numpy/f2py/f2py2e.py
@@ -28,7 +28,7 @@
 from . import f90mod_rules
 from . import __version__
 from . import capi_maps
-from . import backends
+from . import _backends
 
 f2py_version = __version__.version
 numpy_version = __version__.version
@@ -598,7 +598,7 @@ def run_compile():
         sys.argv.pop(backend_index)
     else:
         backend_key = 'distutils'
-    build_backend = backends.get_backend(backend_key)
+    build_backend = _backends.f2py_build_generator(backend_key)
 
     modulename = 'untitled'
     sources = sys.argv[1:]

From 1dc27333ffdf1e39c5d8badb90feadc9fc6562ce Mon Sep 17 00:00:00 2001
From: Rohit Goswami <rog32@hi.is>
Date: Fri, 25 Aug 2023 04:57:33 +0000
Subject: [PATCH 19/37] MAINT: Less absolute paths, update setup.py [f2py]

---
 numpy/f2py/f2py2e.py | 4 ++--
 numpy/f2py/setup.py  | 5 ++++-
 2 files changed, 6 insertions(+), 3 deletions(-)

diff --git a/numpy/f2py/f2py2e.py b/numpy/f2py/f2py2e.py
index 0a6d164b4890..6bd41327a214 100755
--- a/numpy/f2py/f2py2e.py
+++ b/numpy/f2py/f2py2e.py
@@ -28,7 +28,7 @@
 from . import f90mod_rules
 from . import __version__
 from . import capi_maps
-from . import _backends
+from numpy.f2py._backends import f2py_build_generator
 
 f2py_version = __version__.version
 numpy_version = __version__.version
@@ -598,7 +598,7 @@ def run_compile():
         sys.argv.pop(backend_index)
     else:
         backend_key = 'distutils'
-    build_backend = _backends.f2py_build_generator(backend_key)
+    build_backend = f2py_build_generator(backend_key)
 
     modulename = 'untitled'
     sources = sys.argv[1:]
diff --git a/numpy/f2py/setup.py b/numpy/f2py/setup.py
index 499609f96600..075d4683699e 100644
--- a/numpy/f2py/setup.py
+++ b/numpy/f2py/setup.py
@@ -26,10 +26,13 @@
 def configuration(parent_package='', top_path=None):
     config = Configuration('f2py', parent_package, top_path)
     config.add_subpackage('tests')
+    config.add_subpackage('_backends')
     config.add_data_dir('tests/src')
     config.add_data_files(
         'src/fortranobject.c',
-        'src/fortranobject.h')
+        'src/fortranobject.h',
+        'backends/src/meson.build.src',
+    )
     config.add_data_files('*.pyi')
     return config
 

From 42a15acfd7ee398841c2043e8e3c5e3ab9123338 Mon Sep 17 00:00:00 2001
From: Rohit Goswami <rog32@hi.is>
Date: Fri, 25 Aug 2023 14:33:44 +0000
Subject: [PATCH 20/37] MAINT: Move f2py module name functionality

Previously part of np.distutils
---
 numpy/f2py/auxfuncs.py | 20 +++++++++++++++++++-
 numpy/f2py/f2py2e.py   |  3 +--
 2 files changed, 20 insertions(+), 3 deletions(-)

diff --git a/numpy/f2py/auxfuncs.py b/numpy/f2py/auxfuncs.py
index c0864b5bc613..535e324286bd 100644
--- a/numpy/f2py/auxfuncs.py
+++ b/numpy/f2py/auxfuncs.py
@@ -16,6 +16,7 @@
 """
 import pprint
 import sys
+import re
 import types
 from functools import reduce
 from copy import deepcopy
@@ -43,7 +44,7 @@
     'ismodule', 'ismoduleroutine', 'isoptional', 'isprivate', 'isrequired',
     'isroutine', 'isscalar', 'issigned_long_longarray', 'isstring',
     'isstringarray', 'isstring_or_stringarray', 'isstringfunction',
-    'issubroutine',
+    'issubroutine', 'get_f2py_modulename',
     'issubroutine_wrap', 'isthreadsafe', 'isunsigned', 'isunsigned_char',
     'isunsigned_chararray', 'isunsigned_long_long',
     'isunsigned_long_longarray', 'isunsigned_short',
@@ -912,3 +913,20 @@ def deep_merge(dict1, dict2):
         else:
             merged_dict[key] = value
     return merged_dict
+
+_f2py_module_name_match = re.compile(r'\s*python\s*module\s*(?P<name>[\w_]+)',
+                                     re.I).match
+_f2py_user_module_name_match = re.compile(r'\s*python\s*module\s*(?P<name>[\w_]*?'
+                                          r'__user__[\w_]*)', re.I).match
+
+def get_f2py_modulename(source):
+    name = None
+    with open(source) as f:
+        for line in f:
+            m = _f2py_module_name_match(line)
+            if m:
+                if _f2py_user_module_name_match(line): # skip *__user__* names
+                    continue
+                name = m.group('name')
+                break
+    return name
diff --git a/numpy/f2py/f2py2e.py b/numpy/f2py/f2py2e.py
index 6bd41327a214..ef856fd9ee99 100755
--- a/numpy/f2py/f2py2e.py
+++ b/numpy/f2py/f2py2e.py
@@ -616,11 +616,10 @@ def run_compile():
         del sys.argv[i + 1], sys.argv[i]
         sources = sys.argv[1:]
     else:
-        from numpy.distutils.command.build_src import get_f2py_modulename
         pyf_files, sources = filter_files('', '[.]pyf([.]src|)', sources)
         sources = pyf_files + sources
         for f in pyf_files:
-            modulename = get_f2py_modulename(f)
+            modulename = auxfuncs.get_f2py_modulename(f)
             if modulename:
                 break
 

From 6776dba6e1bd8f0769f629b25d8c37f8f5938f43 Mon Sep 17 00:00:00 2001
From: Rohit Goswami <rog32@hi.is>
Date: Fri, 25 Aug 2023 15:16:12 +0000
Subject: [PATCH 21/37] ENH: Handle .pyf files

---
 numpy/f2py/_backends/_meson.py | 3 +++
 numpy/f2py/f2py2e.py           | 9 ++++++---
 2 files changed, 9 insertions(+), 3 deletions(-)

diff --git a/numpy/f2py/_backends/_meson.py b/numpy/f2py/_backends/_meson.py
index 86e0a1a3943c..2dda014d001e 100644
--- a/numpy/f2py/_backends/_meson.py
+++ b/numpy/f2py/_backends/_meson.py
@@ -136,4 +136,7 @@ def _prepare_sources(mname, sources, bdir):
             shutil.copy(generated_source, bdir / generated_source.name)
             extended_sources.append(Path(bdir / generated_source.name).absolute())
             generated_source.unlink()
+    extended_sources = [
+        source for source in extended_sources if not Path(source).suffix == ".pyf"
+    ]
     return extended_sources
diff --git a/numpy/f2py/f2py2e.py b/numpy/f2py/f2py2e.py
index ef856fd9ee99..da509bfb515e 100755
--- a/numpy/f2py/f2py2e.py
+++ b/numpy/f2py/f2py2e.py
@@ -616,8 +616,8 @@ def run_compile():
         del sys.argv[i + 1], sys.argv[i]
         sources = sys.argv[1:]
     else:
-        pyf_files, sources = filter_files('', '[.]pyf([.]src|)', sources)
-        sources = pyf_files + sources
+        pyf_files, _sources = filter_files('', '[.]pyf([.]src|)', sources)
+        sources = pyf_files + _sources
         for f in pyf_files:
             modulename = auxfuncs.get_f2py_modulename(f)
             if modulename:
@@ -642,7 +642,10 @@ def run_compile():
     if backend_key == 'meson':
         outmess('Using meson backend\nWill pass --lower to f2py\nSee https://numpy.org/doc/stable/f2py/buildtools/meson.html')
         f2py_flags.append('--lower')
-    run_main(f" {' '.join(f2py_flags)} -m {modulename} {' '.join(sources)}".split())
+        if pyf_files:
+            run_main(f" {' '.join(f2py_flags)} {' '.join(pyf_files)}".split())
+        else:
+            run_main(f" {' '.join(f2py_flags)} -m {modulename} {' '.join(sources)}".split())
 
     # Now use the builder
     builder = build_backend(

From 0357ab8ed8e09c06ab1c10627762bf34a0265f23 Mon Sep 17 00:00:00 2001
From: Rohit Goswami <rog32@hi.is>
Date: Fri, 25 Aug 2023 15:51:18 +0000
Subject: [PATCH 22/37] TST: Fix typo in isoFortranEnvMap.f90

---
 numpy/f2py/tests/src/f2cmap/isoFortranEnvMap.f90 | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/numpy/f2py/tests/src/f2cmap/isoFortranEnvMap.f90 b/numpy/f2py/tests/src/f2cmap/isoFortranEnvMap.f90
index 3f0e12c76833..1e1dc1d4054b 100644
--- a/numpy/f2py/tests/src/f2cmap/isoFortranEnvMap.f90
+++ b/numpy/f2py/tests/src/f2cmap/isoFortranEnvMap.f90
@@ -4,6 +4,6 @@ subroutine func1(n, x, res)
         integer(int64), intent(in) :: n
         real(real64), intent(in) :: x(n)
         real(real64), intent(out) :: res
-Cf2py   intent(hide) :: n
+!f2py   intent(hide) :: n
         res = sum(x)
       end

From 5faec2f6d4b8973525e75f137b3e6aec6c0e3a20 Mon Sep 17 00:00:00 2001
From: Rohit Goswami <rog32@hi.is>
Date: Fri, 25 Aug 2023 15:52:20 +0000
Subject: [PATCH 23/37] MAINT: Typo in f2py2e support for pyf files

---
 numpy/f2py/f2py2e.py | 1 +
 1 file changed, 1 insertion(+)

diff --git a/numpy/f2py/f2py2e.py b/numpy/f2py/f2py2e.py
index da509bfb515e..6b63a6c6b0b0 100755
--- a/numpy/f2py/f2py2e.py
+++ b/numpy/f2py/f2py2e.py
@@ -610,6 +610,7 @@ def run_compile():
             del sys.argv[i + 1], sys.argv[i]
             sources = sys.argv[1:]
 
+    pyf_files = []
     if '-m' in sys.argv:
         i = sys.argv.index('-m')
         modulename = sys.argv[i + 1]

From 5b794876c933ead944544c7450888ed9635f03cc Mon Sep 17 00:00:00 2001
From: Rohit Goswami <rog32@hi.is>
Date: Fri, 25 Aug 2023 16:13:01 +0000
Subject: [PATCH 24/37] DOC: Add release note for --backend

---
 doc/release/upcoming_changes/24532.new_feature.rst | 5 +++++
 1 file changed, 5 insertions(+)
 create mode 100644 doc/release/upcoming_changes/24532.new_feature.rst

diff --git a/doc/release/upcoming_changes/24532.new_feature.rst b/doc/release/upcoming_changes/24532.new_feature.rst
new file mode 100644
index 000000000000..6c89d9dd7574
--- /dev/null
+++ b/doc/release/upcoming_changes/24532.new_feature.rst
@@ -0,0 +1,5 @@
+``meson`` backend for ``f2py``
+------------------------------
+``f2py`` now accepts the ``--backend meson`` option. This is the default option
+for Python ``3.12`` on-wards. Older versions will still default to ``--backend
+distutils``.

From faadb6d61013002885125e0b52f86800617890b3 Mon Sep 17 00:00:00 2001
From: Rohit Goswami <rog32@hi.is>
Date: Fri, 25 Aug 2023 16:18:19 +0000
Subject: [PATCH 25/37] MAINT: Conditional switch for Python 3.12 [f2py]

---
 numpy/f2py/f2py2e.py | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/numpy/f2py/f2py2e.py b/numpy/f2py/f2py2e.py
index 6b63a6c6b0b0..43fbcc66f6c6 100755
--- a/numpy/f2py/f2py2e.py
+++ b/numpy/f2py/f2py2e.py
@@ -598,6 +598,10 @@ def run_compile():
         sys.argv.pop(backend_index)
     else:
         backend_key = 'distutils'
+
+    if sys.version_info >= (3, 12) and backend_key == 'distutils':
+        outmess('Cannot use distutils backend with Python 3.12, using meson backend instead.')
+        backend_key = 'meson'
     build_backend = f2py_build_generator(backend_key)
 
     modulename = 'untitled'

From 82a4f8fd347f8e85f1aab363a67494f9fde2006f Mon Sep 17 00:00:00 2001
From: Rohit Goswami <rog32@hi.is>
Date: Fri, 25 Aug 2023 21:47:47 +0000
Subject: [PATCH 26/37] MAINT: No absolute paths in backend [f2py-meson]

The files are copied over anyway, this makes it easier to extend the
generated skeleton
---
 numpy/f2py/_backends/_meson.py | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/numpy/f2py/_backends/_meson.py b/numpy/f2py/_backends/_meson.py
index 2dda014d001e..90bdce86f0ed 100644
--- a/numpy/f2py/_backends/_meson.py
+++ b/numpy/f2py/_backends/_meson.py
@@ -134,9 +134,11 @@ def _prepare_sources(mname, sources, bdir):
     for generated_source in generated_sources:
         if generated_source.exists():
             shutil.copy(generated_source, bdir / generated_source.name)
-            extended_sources.append(Path(bdir / generated_source.name).absolute())
+            extended_sources.append(generated_source.name)
             generated_source.unlink()
     extended_sources = [
-        source for source in extended_sources if not Path(source).suffix == ".pyf"
+        Path(source).name
+        for source in extended_sources
+        if not Path(source).suffix == ".pyf"
     ]
     return extended_sources

From 65854588d9dc3e0ef8e274c246bcee0ca4e30fd0 Mon Sep 17 00:00:00 2001
From: Rohit Goswami <rog32@hi.is>
Date: Fri, 25 Aug 2023 21:53:04 +0000
Subject: [PATCH 27/37] MAINT: Prettier generated meson.build files [f2py]

---
 numpy/f2py/_backends/_meson.py           | 4 ++--
 numpy/f2py/_backends/src/meson.build.src | 5 ++++-
 2 files changed, 6 insertions(+), 3 deletions(-)

diff --git a/numpy/f2py/_backends/_meson.py b/numpy/f2py/_backends/_meson.py
index 90bdce86f0ed..91fcabc0451b 100644
--- a/numpy/f2py/_backends/_meson.py
+++ b/numpy/f2py/_backends/_meson.py
@@ -49,8 +49,8 @@ def initialize_template(self) -> None:
         self.substitutions["modulename"] = self.modulename
 
     def sources_substitution(self) -> None:
-        self.substitutions["source_list"] = ", ".join(
-            [f"'{source}'" for source in self.sources]
+        self.substitutions["source_list"] = ",\n".join(
+            [f"                     '{source}'" for source in self.sources]
         )
 
     def generate_meson_build(self):
diff --git a/numpy/f2py/_backends/src/meson.build.src b/numpy/f2py/_backends/src/meson.build.src
index 84b8f169dbb6..c3149164c2e7 100644
--- a/numpy/f2py/_backends/src/meson.build.src
+++ b/numpy/f2py/_backends/src/meson.build.src
@@ -28,7 +28,10 @@ fortranobject_c = incdir_f2py / 'fortranobject.c'
 inc_np = include_directories(incdir_numpy, incdir_f2py)
 
 py.extension_module('${modulename}',
-                     [${source_list}, fortranobject_c],
+                     [
+${source_list},
+                     fortranobject_c
+                     ],
                      include_directories: [inc_np],
                      dependencies : [py_dep],
                      install : true)

From f85581e90f264026d47b85522e02ef000a992ae5 Mon Sep 17 00:00:00 2001
From: Rohit Goswami <rog32@hi.is>
Date: Fri, 25 Aug 2023 22:20:50 +0000
Subject: [PATCH 28/37] ENH: Add meson's dependency(blah) to f2py

---
 numpy/f2py/_backends/_backend.py         |  2 ++
 numpy/f2py/_backends/_meson.py           | 16 ++++++++++++++--
 numpy/f2py/_backends/src/meson.build.src |  5 ++++-
 numpy/f2py/f2py2e.py                     | 15 ++++++++++++++-
 4 files changed, 34 insertions(+), 4 deletions(-)

diff --git a/numpy/f2py/_backends/_backend.py b/numpy/f2py/_backends/_backend.py
index 9fea9d243137..a7d43d2587b2 100644
--- a/numpy/f2py/_backends/_backend.py
+++ b/numpy/f2py/_backends/_backend.py
@@ -21,6 +21,7 @@ def __init__(
         flib_flags,
         setup_flags,
         remove_build_dir,
+        extra_dat,
     ):
         self.modulename = modulename
         self.sources = sources
@@ -37,6 +38,7 @@ def __init__(
         self.flib_flags = flib_flags
         self.setup_flags = setup_flags
         self.remove_build_dir = remove_build_dir
+        self.extra_dat = extra_dat
 
     @abstractmethod
     def compile(self) -> None:
diff --git a/numpy/f2py/_backends/_meson.py b/numpy/f2py/_backends/_meson.py
index 91fcabc0451b..eef4622c2353 100644
--- a/numpy/f2py/_backends/_meson.py
+++ b/numpy/f2py/_backends/_meson.py
@@ -18,6 +18,7 @@ def __init__(
         self,
         modulename: str,
         sources: list[Path],
+        deps: list[str],
         object_files: list[Path],
         linker_args: list[str],
         c_args: list[str],
@@ -27,11 +28,13 @@ def __init__(
             Path(__file__).parent.absolute() / "src" / "meson.build.src"
         )
         self.sources = sources
+        self.deps = deps
         self.substitutions = {}
         self.objects = object_files
         self.pipeline = [
             self.initialize_template,
             self.sources_substitution,
+            self.deps_substitution,
         ]
 
     def meson_build_template(self) -> str:
@@ -49,8 +52,15 @@ def initialize_template(self) -> None:
         self.substitutions["modulename"] = self.modulename
 
     def sources_substitution(self) -> None:
-        self.substitutions["source_list"] = ",\n".join(
-            [f"                     '{source}'" for source in self.sources]
+        indent = " " * 21
+        self.substitutions["source_list"] = f",\n{indent}".join(
+            [f"'{source}'" for source in self.sources]
+        )
+
+    def deps_substitution(self) -> None:
+        indent = " " * 21
+        self.substitutions["dep_list"] = f",\n{indent}".join(
+            [f"dependency('{dep}')" for dep in self.deps]
         )
 
     def generate_meson_build(self):
@@ -68,6 +78,7 @@ def __init__(self, *args, **kwargs):
             stacklevel=2,
         )
         super().__init__(*args, **kwargs)
+        self.dependencies = self.extra_dat.get("dependencies", [])
         self.meson_build_dir = "bbdir"
 
     def _move_exec_to_root(self, build_dir: Path):
@@ -88,6 +99,7 @@ def write_meson_build(self, build_dir: Path) -> None:
         meson_template = MesonTemplate(
             self.modulename,
             self.sources,
+            self.dependencies,
             self.extra_objects,
             self.flib_flags,
             self.fc_flags,
diff --git a/numpy/f2py/_backends/src/meson.build.src b/numpy/f2py/_backends/src/meson.build.src
index c3149164c2e7..29d711f7d37f 100644
--- a/numpy/f2py/_backends/src/meson.build.src
+++ b/numpy/f2py/_backends/src/meson.build.src
@@ -33,5 +33,8 @@ ${source_list},
                      fortranobject_c
                      ],
                      include_directories: [inc_np],
-                     dependencies : [py_dep],
+                     dependencies : [
+                     py_dep,
+${dep_list}
+                     ],
                      install : true)
diff --git a/numpy/f2py/f2py2e.py b/numpy/f2py/f2py2e.py
index 43fbcc66f6c6..d31c87f10fbd 100755
--- a/numpy/f2py/f2py2e.py
+++ b/numpy/f2py/f2py2e.py
@@ -19,6 +19,7 @@
 import pprint
 import re
 from pathlib import Path
+from itertools import dropwhile
 
 from . import crackfortran
 from . import rules
@@ -549,7 +550,18 @@ def run_compile():
     if f2py_flags2 and f2py_flags2[-1] != ':':
         f2py_flags2.append(':')
     f2py_flags.extend(f2py_flags2)
-
+    # Find the start and end indices of the "deps:" section
+    start_idx = next((i for i, a in enumerate(sys.argv) if a == "deps:"), None)
+    end_idx = next((i for i, a in enumerate(sys.argv) if a == ":" and i > start_idx), None) if start_idx is not None else None
+    # Extract dependencies and remove them from sys.argv
+    if start_idx is not None and end_idx is not None:
+        dependencies = sys.argv[start_idx + 1:end_idx]
+        del sys.argv[start_idx:end_idx + 1]
+    elif start_idx is not None:
+        dependencies = list(dropwhile(lambda x: x != ":", sys.argv[start_idx + 1:]))
+        del sys.argv[start_idx:]
+    else:
+        dependencies = []
     sys.argv = [_m for _m in sys.argv if _m not in f2py_flags2]
     _reg3 = re.compile(
         r'--((f(90)?compiler(-exec|)|compiler)=|help-compiler)')
@@ -669,6 +681,7 @@ def run_compile():
         flib_flags,
         setup_flags,
         remove_build_dir,
+        {"dependencies": dependencies},
     )
 
     builder.compile()

From 16f22eea8628a0be58ead8d211884de83b775f8a Mon Sep 17 00:00:00 2001
From: Rohit Goswami <rog32@hi.is>
Date: Fri, 25 Aug 2023 22:49:56 +0000
Subject: [PATCH 29/37] DOC: Document the new flag

---
 numpy/f2py/f2py2e.py | 15 ++++++++++++++-
 1 file changed, 14 insertions(+), 1 deletion(-)

diff --git a/numpy/f2py/f2py2e.py b/numpy/f2py/f2py2e.py
index d31c87f10fbd..3a6a9c429726 100755
--- a/numpy/f2py/f2py2e.py
+++ b/numpy/f2py/f2py2e.py
@@ -128,7 +128,7 @@
   -v               Print f2py version ID and exit.
 
 
-numpy.distutils options (only effective with -c):
+build backend options (only effective with -c):
 
   --fcompiler=         Specify Fortran compiler type by vendor
   --compiler=          Specify C compiler type (as defined by distutils)
@@ -143,6 +143,19 @@
   --noopt              Compile without optimization
   --noarch             Compile without arch-dependent optimization
   --debug              Compile with debugging information
+  deps:                <dependency1> <dependency2> ... :
+                       Specify additional dependencies that the module relies on.
+                       List dependencies separated by spaces, and use `:' to
+                       signify the end of the dependency list. Dependencies are
+                       stored in a list for further processing.
+
+                       Example: deps: lapack scalapack :
+                       This will identify "lapack" and "scalapack" as dependencies
+                       and remove them from argv, leaving a dependencies list
+                       containing ["lapack", "scalapack"].
+
+                       Note: The trailing `:' is required to signify the end of
+                       the dependency list. This is only relevant for the meson backend.
 
 Extra options (only effective with -c):
 

From c0c6bf18874e54b1b0f4f25e02cb7b386e5b422e Mon Sep 17 00:00:00 2001
From: Rohit Goswami <rog32@hi.is>
Date: Sat, 26 Aug 2023 10:26:38 +0000
Subject: [PATCH 30/37] MAINT: Simplify and rename backend template [f2py]

Co-authored-by: rgommers <rgommers@users.noreply.github.com>
---
 numpy/f2py/_backends/_meson.py                                  | 2 +-
 .../_backends/{src/meson.build.src => meson.build.template}     | 0
 2 files changed, 1 insertion(+), 1 deletion(-)
 rename numpy/f2py/_backends/{src/meson.build.src => meson.build.template} (100%)

diff --git a/numpy/f2py/_backends/_meson.py b/numpy/f2py/_backends/_meson.py
index eef4622c2353..48130edbe464 100644
--- a/numpy/f2py/_backends/_meson.py
+++ b/numpy/f2py/_backends/_meson.py
@@ -25,7 +25,7 @@ def __init__(
     ):
         self.modulename = modulename
         self.build_template_path = (
-            Path(__file__).parent.absolute() / "src" / "meson.build.src"
+            Path(__file__).parent.absolute() / "meson.build.template"
         )
         self.sources = sources
         self.deps = deps
diff --git a/numpy/f2py/_backends/src/meson.build.src b/numpy/f2py/_backends/meson.build.template
similarity index 100%
rename from numpy/f2py/_backends/src/meson.build.src
rename to numpy/f2py/_backends/meson.build.template

From fa06f8d6ecfa776edb10212a415d72970e272256 Mon Sep 17 00:00:00 2001
From: Rohit Goswami <rog32@hi.is>
Date: Sat, 26 Aug 2023 10:46:50 +0000
Subject: [PATCH 31/37] ENH: Support build_type via --debug [f2py-meson]

---
 numpy/f2py/_backends/_meson.py            | 8 +++++++-
 numpy/f2py/_backends/meson.build.template | 8 +++++---
 2 files changed, 12 insertions(+), 4 deletions(-)

diff --git a/numpy/f2py/_backends/_meson.py b/numpy/f2py/_backends/_meson.py
index 48130edbe464..5e4e68382459 100644
--- a/numpy/f2py/_backends/_meson.py
+++ b/numpy/f2py/_backends/_meson.py
@@ -22,6 +22,7 @@ def __init__(
         object_files: list[Path],
         linker_args: list[str],
         c_args: list[str],
+        build_type: str,
     ):
         self.modulename = modulename
         self.build_template_path = (
@@ -36,6 +37,7 @@ def __init__(
             self.sources_substitution,
             self.deps_substitution,
         ]
+        self.build_type = build_type
 
     def meson_build_template(self) -> str:
         if not self.build_template_path.is_file():
@@ -48,8 +50,8 @@ def meson_build_template(self) -> str:
         return self.build_template_path.read_text()
 
     def initialize_template(self) -> None:
-        """Initialize with module name."""
         self.substitutions["modulename"] = self.modulename
+        self.substitutions["buildtype"] = self.build_type
 
     def sources_substitution(self) -> None:
         indent = " " * 21
@@ -80,6 +82,9 @@ def __init__(self, *args, **kwargs):
         super().__init__(*args, **kwargs)
         self.dependencies = self.extra_dat.get("dependencies", [])
         self.meson_build_dir = "bbdir"
+        self.build_type = (
+            "debug" if any("debug" in flag for flag in self.fc_flags) else "release"
+        )
 
     def _move_exec_to_root(self, build_dir: Path):
         walk_dir = Path(build_dir) / self.meson_build_dir
@@ -103,6 +108,7 @@ def write_meson_build(self, build_dir: Path) -> None:
             self.extra_objects,
             self.flib_flags,
             self.fc_flags,
+            self.build_type,
         )
         src = meson_template.generate_meson_build()
         Path(build_dir).mkdir(parents=True, exist_ok=True)
diff --git a/numpy/f2py/_backends/meson.build.template b/numpy/f2py/_backends/meson.build.template
index 29d711f7d37f..545e3995218a 100644
--- a/numpy/f2py/_backends/meson.build.template
+++ b/numpy/f2py/_backends/meson.build.template
@@ -2,10 +2,12 @@ project('${modulename}',
         ['c', 'fortran'],
         version : '0.1',
         meson_version: '>= 1.1.0',
-        default_options : ['warning_level=2'])
+        default_options : [
+                            'warning_level=1',
+                            'buildtype=${buildtype}'
+                          ])
 
-py_mod = import('python')
-py = py_mod.find_installation(pure: false)
+py = import('python').find_installation(pure: false)
 py_dep = py.dependency()
 
 incdir_numpy = run_command(py,

From 8841647b368d6125624162a564ea7f32d9c8624c Mon Sep 17 00:00:00 2001
From: Rohit Goswami <rog32@hi.is>
Date: Sat, 26 Aug 2023 10:58:12 +0000
Subject: [PATCH 32/37] MAINT,DOC: Reduce warn,rework doc [f2py-meson]

Co-authored-by: rgommers <rgommers@users.noreply.github.com>
---
 doc/release/upcoming_changes/24532.new_feature.rst | 9 ++++++++-
 numpy/f2py/_backends/_distutils.py                 | 5 ++---
 numpy/f2py/_backends/_meson.py                     | 5 -----
 numpy/f2py/f2py2e.py                               | 6 ------
 4 files changed, 10 insertions(+), 15 deletions(-)

diff --git a/doc/release/upcoming_changes/24532.new_feature.rst b/doc/release/upcoming_changes/24532.new_feature.rst
index 6c89d9dd7574..504b1d431cff 100644
--- a/doc/release/upcoming_changes/24532.new_feature.rst
+++ b/doc/release/upcoming_changes/24532.new_feature.rst
@@ -1,5 +1,12 @@
 ``meson`` backend for ``f2py``
 ------------------------------
-``f2py`` now accepts the ``--backend meson`` option. This is the default option
+``f2py`` in compile mode (i.e. ``f2py -c``) now accepts the ``--backend meson`` option. This is the default option
 for Python ``3.12`` on-wards. Older versions will still default to ``--backend
 distutils``.
+
+To support this in realistic use-cases, in compile mode ``f2py`` takes a
+``--dep`` flag one or many times which maps to ``dependency()`` calls in the
+``meson`` backend, and does nothing in the ``distutils`` backend.
+
+
+There are no changes for users of ``f2py`` only as a code generator, i.e. without ``-c``.
diff --git a/numpy/f2py/_backends/_distutils.py b/numpy/f2py/_backends/_distutils.py
index efc7a98b7692..e548fc543010 100644
--- a/numpy/f2py/_backends/_distutils.py
+++ b/numpy/f2py/_backends/_distutils.py
@@ -13,8 +13,8 @@
 class DistutilsBackend(Backend):
     def __init__(sef, *args, **kwargs):
         warnings.warn(
-            "distutils has been deprecated since NumPy 2.16."
-            "Use the MesonBackend instead, or generate wrappers"
+            "distutils has been deprecated since NumPy 1.26."
+            "Use the Meson backend instead, or generate wrappers"
             "without -c and use a custom build script",
             VisibleDeprecationWarning,
             stacklevel=2,
@@ -33,7 +33,6 @@ def compile(self):
             "libraries": self.libraries,
             "define_macros": self.define_macros,
             "undef_macros": self.undef_macros,
-            # TODO: Handle extra_objects in meson
             "extra_objects": self.extra_objects,
             "f2py_options": self.f2py_flags,
         }
diff --git a/numpy/f2py/_backends/_meson.py b/numpy/f2py/_backends/_meson.py
index 5e4e68382459..3176a5e08f30 100644
--- a/numpy/f2py/_backends/_meson.py
+++ b/numpy/f2py/_backends/_meson.py
@@ -74,11 +74,6 @@ def generate_meson_build(self):
 
 class MesonBackend(Backend):
     def __init__(self, *args, **kwargs):
-        warnings.warn(
-            "The MesonBackend is experimental and may change in the future."
-            "--build-dir should be used to customize the generated skeleton.",
-            stacklevel=2,
-        )
         super().__init__(*args, **kwargs)
         self.dependencies = self.extra_dat.get("dependencies", [])
         self.meson_build_dir = "bbdir"
diff --git a/numpy/f2py/f2py2e.py b/numpy/f2py/f2py2e.py
index 3a6a9c429726..95638a880314 100755
--- a/numpy/f2py/f2py2e.py
+++ b/numpy/f2py/f2py2e.py
@@ -724,12 +724,6 @@ def main():
         pass
 
     if '-c' in sys.argv[1:]:
-        import warnings
-        warnings.warn('Using f2py to compile code without generating files '
-                      'first was largely handled by distutils which has been removed in Python 3.12.'
-                      'The meson replacement is a work in progress, consider running without -c.'
-                      'Recall that the build can be customized with --build-dir',
-                      stacklevel=2)
         run_compile()
     else:
         run_main(sys.argv[1:])

From 8f214a0118ef3ac0c7739706753663923086b302 Mon Sep 17 00:00:00 2001
From: Rohit Goswami <rog32@hi.is>
Date: Sat, 26 Aug 2023 11:08:32 +0000
Subject: [PATCH 33/37] ENH: Rework deps: to --dep calls [f2py-meson]

Also shows how incremental updates to the parser can be done.
---
 numpy/f2py/f2py2e.py | 42 +++++++++++++++++++++---------------------
 1 file changed, 21 insertions(+), 21 deletions(-)

diff --git a/numpy/f2py/f2py2e.py b/numpy/f2py/f2py2e.py
index 95638a880314..2422c61a1f45 100755
--- a/numpy/f2py/f2py2e.py
+++ b/numpy/f2py/f2py2e.py
@@ -20,6 +20,7 @@
 import re
 from pathlib import Path
 from itertools import dropwhile
+import argparse
 
 from . import crackfortran
 from . import rules
@@ -143,20 +144,16 @@
   --noopt              Compile without optimization
   --noarch             Compile without arch-dependent optimization
   --debug              Compile with debugging information
-  deps:                <dependency1> <dependency2> ... :
-                       Specify additional dependencies that the module relies on.
-                       List dependencies separated by spaces, and use `:' to
-                       signify the end of the dependency list. Dependencies are
-                       stored in a list for further processing.
+  --dep                <dependency>
+                       Specify a meson dependencies for the module. This may
+                       be passed multiple times for multiple dependencies.
+                       Dependencies are stored in a list for further processing.
 
-                       Example: deps: lapack scalapack :
+                       Example: --dep lapack --dep scalapack
                        This will identify "lapack" and "scalapack" as dependencies
                        and remove them from argv, leaving a dependencies list
                        containing ["lapack", "scalapack"].
 
-                       Note: The trailing `:' is required to signify the end of
-                       the dependency list. This is only relevant for the meson backend.
-
 Extra options (only effective with -c):
 
   --link-<resource>    Link extension module with <resource> as defined
@@ -518,6 +515,17 @@ def get_prefix(module):
     p = os.path.dirname(os.path.dirname(module.__file__))
     return p
 
+def preparse_sysargv():
+    # To keep backwards bug compatibility, newer flags are handled by argparse,
+    # and `sys.argv` is passed to the rest of `f2py` as is.
+    parser = argparse.ArgumentParser(add_help=False)
+    parser.add_argument("--dep", action="append", dest="dependencies")
+    args, remaining_argv = parser.parse_known_args()
+    sys.argv = [sys.argv[0]] + remaining_argv
+    return {
+        "dependencies": args.dependencies or [],
+    }
+
 
 def run_compile():
     """
@@ -525,6 +533,10 @@ def run_compile():
     """
     import tempfile
 
+    # Collect dependency flags, preprocess sys.argv
+    argparse_res = preparse_sysargv()
+    dependencies = argparse_res["dependencies"]
+
     i = sys.argv.index('-c')
     del sys.argv[i]
 
@@ -563,18 +575,6 @@ def run_compile():
     if f2py_flags2 and f2py_flags2[-1] != ':':
         f2py_flags2.append(':')
     f2py_flags.extend(f2py_flags2)
-    # Find the start and end indices of the "deps:" section
-    start_idx = next((i for i, a in enumerate(sys.argv) if a == "deps:"), None)
-    end_idx = next((i for i, a in enumerate(sys.argv) if a == ":" and i > start_idx), None) if start_idx is not None else None
-    # Extract dependencies and remove them from sys.argv
-    if start_idx is not None and end_idx is not None:
-        dependencies = sys.argv[start_idx + 1:end_idx]
-        del sys.argv[start_idx:end_idx + 1]
-    elif start_idx is not None:
-        dependencies = list(dropwhile(lambda x: x != ":", sys.argv[start_idx + 1:]))
-        del sys.argv[start_idx:]
-    else:
-        dependencies = []
     sys.argv = [_m for _m in sys.argv if _m not in f2py_flags2]
     _reg3 = re.compile(
         r'--((f(90)?compiler(-exec|)|compiler)=|help-compiler)')

From bc376848faddfce208bf5d0143debb1496b0e062 Mon Sep 17 00:00:00 2001
From: Rohit Goswami <rog32@hi.is>
Date: Sat, 26 Aug 2023 11:13:22 +0000
Subject: [PATCH 34/37] MAINT,DOC: Add --backend to argparse, add docs

---
 numpy/f2py/f2py2e.py | 39 ++++++++++++++++++++++-----------------
 1 file changed, 22 insertions(+), 17 deletions(-)

diff --git a/numpy/f2py/f2py2e.py b/numpy/f2py/f2py2e.py
index 2422c61a1f45..1cfe8cddd68c 100755
--- a/numpy/f2py/f2py2e.py
+++ b/numpy/f2py/f2py2e.py
@@ -144,8 +144,9 @@
   --noopt              Compile without optimization
   --noarch             Compile without arch-dependent optimization
   --debug              Compile with debugging information
+
   --dep                <dependency>
-                       Specify a meson dependencies for the module. This may
+                       Specify a meson dependency for the module. This may
                        be passed multiple times for multiple dependencies.
                        Dependencies are stored in a list for further processing.
 
@@ -154,6 +155,12 @@
                        and remove them from argv, leaving a dependencies list
                        containing ["lapack", "scalapack"].
 
+  --backend            <backend_type>
+                       Specify the build backend for the compilation process.
+                       The supported backends are 'meson' and 'distutils'.
+                       If not specified, defaults to 'distutils'. On
+                       Python 3.12 or higher, the default is 'meson'.
+
 Extra options (only effective with -c):
 
   --link-<resource>    Link extension module with <resource> as defined
@@ -520,13 +527,21 @@ def preparse_sysargv():
     # and `sys.argv` is passed to the rest of `f2py` as is.
     parser = argparse.ArgumentParser(add_help=False)
     parser.add_argument("--dep", action="append", dest="dependencies")
+    parser.add_argument("--backend", choices=['meson', 'distutils'], default='distutils')
+
     args, remaining_argv = parser.parse_known_args()
     sys.argv = [sys.argv[0]] + remaining_argv
+
+    backend_key = args.backend
+    if sys.version_info >= (3, 12) and backend_key == 'distutils':
+        outmess('Cannot use distutils backend with Python 3.12, using meson backend instead.')
+        backend_key = 'meson'
+
     return {
         "dependencies": args.dependencies or [],
+        "backend": backend_key
     }
 
-
 def run_compile():
     """
     Do it all in one call!
@@ -534,8 +549,11 @@ def run_compile():
     import tempfile
 
     # Collect dependency flags, preprocess sys.argv
-    argparse_res = preparse_sysargv()
-    dependencies = argparse_res["dependencies"]
+    argy = preparse_sysargv()
+    dependencies = argy["dependencies"]
+    backend_key = argy["backend"]
+    build_backend = f2py_build_generator(backend_key)
+
 
     i = sys.argv.index('-c')
     del sys.argv[i]
@@ -616,19 +634,6 @@ def run_compile():
     if '--quiet' in f2py_flags:
         setup_flags.append('--quiet')
 
-    # Check for and remove --backend first
-    if '--backend' in sys.argv:
-        backend_index = sys.argv.index('--backend')
-        backend_key = sys.argv.pop(backend_index + 1)
-        sys.argv.pop(backend_index)
-    else:
-        backend_key = 'distutils'
-
-    if sys.version_info >= (3, 12) and backend_key == 'distutils':
-        outmess('Cannot use distutils backend with Python 3.12, using meson backend instead.')
-        backend_key = 'meson'
-    build_backend = f2py_build_generator(backend_key)
-
     modulename = 'untitled'
     sources = sys.argv[1:]
 

From 4e3336b93ed1c00f06fb90c8148c8b071851657a Mon Sep 17 00:00:00 2001
From: Rohit Goswami <rog32@hi.is>
Date: Sat, 26 Aug 2023 11:33:33 +0000
Subject: [PATCH 35/37] MAINT: Rename meson template [f2py-meson]

---
 numpy/f2py/setup.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/numpy/f2py/setup.py b/numpy/f2py/setup.py
index 075d4683699e..98f1e9aaae84 100644
--- a/numpy/f2py/setup.py
+++ b/numpy/f2py/setup.py
@@ -31,7 +31,7 @@ def configuration(parent_package='', top_path=None):
     config.add_data_files(
         'src/fortranobject.c',
         'src/fortranobject.h',
-        'backends/src/meson.build.src',
+        'backends/meson.build.template',
     )
     config.add_data_files('*.pyi')
     return config

From 518074eb5d3b449d5a6b510a23b1b955684ea89a Mon Sep 17 00:00:00 2001
From: Rohit Goswami <rog32@hi.is>
Date: Tue, 29 Aug 2023 12:39:47 +0000
Subject: [PATCH 36/37] MAINT: Add meson.build for f2py

Should address https://github.com/numpy/numpy/pull/22225#issuecomment-1697208937
---
 numpy/f2py/meson.build | 14 ++++++++++++++
 numpy/meson.build      |  1 +
 2 files changed, 15 insertions(+)
 create mode 100644 numpy/f2py/meson.build

diff --git a/numpy/f2py/meson.build b/numpy/f2py/meson.build
new file mode 100644
index 000000000000..7a116faf5222
--- /dev/null
+++ b/numpy/f2py/meson.build
@@ -0,0 +1,14 @@
+py.install_sources(
+  [
+    'src/fortranobject.c',
+    'src/fortranobject.h',
+  ],
+  subdir: 'numpy/f2py/src'
+)
+
+py.install_sources(
+  [
+    '_backends/meson.build.template',
+  ],
+  subdir: 'numpy/f2py/_backends'
+)
diff --git a/numpy/meson.build b/numpy/meson.build
index a4509bc33067..f3f29138c954 100644
--- a/numpy/meson.build
+++ b/numpy/meson.build
@@ -413,3 +413,4 @@ subdir('core')
 subdir('fft')
 subdir('linalg')
 subdir('random')
+subdir('f2py')

From cc92d2c038c18b16c637a46eef85790734f1c37b Mon Sep 17 00:00:00 2001
From: Ralf Gommers <ralf.gommers@gmail.com>
Date: Tue, 5 Sep 2023 17:23:35 +0200
Subject: [PATCH 37/37] BLD: remove duplicate f2py handling in meson.build
 files

---
 numpy/f2py/meson.build | 14 --------------
 numpy/meson.build      |  1 -
 2 files changed, 15 deletions(-)
 delete mode 100644 numpy/f2py/meson.build

diff --git a/numpy/f2py/meson.build b/numpy/f2py/meson.build
deleted file mode 100644
index 7a116faf5222..000000000000
--- a/numpy/f2py/meson.build
+++ /dev/null
@@ -1,14 +0,0 @@
-py.install_sources(
-  [
-    'src/fortranobject.c',
-    'src/fortranobject.h',
-  ],
-  subdir: 'numpy/f2py/src'
-)
-
-py.install_sources(
-  [
-    '_backends/meson.build.template',
-  ],
-  subdir: 'numpy/f2py/_backends'
-)
diff --git a/numpy/meson.build b/numpy/meson.build
index f3f29138c954..a4509bc33067 100644
--- a/numpy/meson.build
+++ b/numpy/meson.build
@@ -413,4 +413,3 @@ subdir('core')
 subdir('fft')
 subdir('linalg')
 subdir('random')
-subdir('f2py')