Shorten dviread helper definitions.

anntzer · anntzer · commit df4480c18a0f · 2023-11-08T19:06:06.000+01:00
diff --git a/lib/matplotlib/dviread.py b/lib/matplotlib/dviread.py
@@ -125,64 +125,28 @@ def glyph_name_or_index(self):
 
 # Opcode argument parsing
 #
-# Each of the following functions takes a Dvi object and delta,
-# which is the difference between the opcode and the minimum opcode
-# with the same meaning. Dvi opcodes often encode the number of
-# argument bytes in this delta.
-
-def _arg_raw(dvi, delta):
-    """Return *delta* without reading anything more from the dvi file."""
-    return delta
-
-
-def _arg(nbytes, signed, dvi, _):
-    """
-    Read *nbytes* bytes, returning the bytes interpreted as a signed integer
-    if *signed* is true, unsigned otherwise.
-    """
-    return dvi._arg(nbytes, signed)
-
-
-def _arg_slen(dvi, delta):
-    """
-    Read *delta* bytes, returning None if *delta* is zero, and the bytes
-    interpreted as a signed integer otherwise.
-    """
-    if delta == 0:
-        return None
-    return dvi._arg(delta, True)
-
-
-def _arg_slen1(dvi, delta):
-    """
-    Read *delta*+1 bytes, returning the bytes interpreted as signed.
-    """
-    return dvi._arg(delta + 1, True)
-
-
-def _arg_ulen1(dvi, delta):
-    """
-    Read *delta*+1 bytes, returning the bytes interpreted as unsigned.
-    """
-    return dvi._arg(delta + 1, False)
-
-
-def _arg_olen1(dvi, delta):
-    """
-    Read *delta*+1 bytes, returning the bytes interpreted as
-    unsigned integer for 0<=*delta*<3 and signed if *delta*==3.
-    """
-    return dvi._arg(delta + 1, delta == 3)
-
-
-_arg_mapping = dict(raw=_arg_raw,
-                    u1=partial(_arg, 1, False),
-                    u4=partial(_arg, 4, False),
-                    s4=partial(_arg, 4, True),
-                    slen=_arg_slen,
-                    olen1=_arg_olen1,
-                    slen1=_arg_slen1,
-                    ulen1=_arg_ulen1)
+# Each of the following functions takes a Dvi object and delta, which is the
+# difference between the opcode and the minimum opcode with the same meaning.
+# Dvi opcodes often encode the number of argument bytes in this delta.
+_arg_mapping = dict(
+    # raw: Return delta as is.
+    raw=lambda dvi, delta: delta,
+    # u1: Read 1 byte as an unsigned number.
+    u1=lambda dvi, delta: dvi._arg(1, signed=False),
+    # u4: Read 4 bytes as an unsigned number.
+    u4=lambda dvi, delta: dvi._arg(4, signed=False),
+    # s4: Read 4 bytes as a signed number.
+    s4=lambda dvi, delta: dvi._arg(4, signed=True),
+    # slen: Read delta bytes as a signed number, or None if delta is None.
+    slen=lambda dvi, delta: dvi._arg(delta, signed=True) if delta else None,
+    # slen1: Read (delta + 1) bytes as a signed number.
+    slen1=lambda dvi, delta: dvi._arg(delta + 1, signed=True),
+    # ulen1: Read (delta + 1) bytes as an unsigned number.
+    ulen1=lambda dvi, delta: dvi._arg(delta + 1, signed=False),
+    # olen1: Read (delta + 1) bytes as an unsigned number if less than 4 bytes,
+    # as a signed number if 4 bytes.
+    olen1=lambda dvi, delta: dvi._arg(delta + 1, signed=(delta == 3)),
+)
 
 
 def _dispatch(table, min, max=None, state=None, args=('raw',)):
