/*

* This file includes functions to transform a concrete syntax tree (CST) to

* an abstract syntax tree (AST). The main function is PyAST_FromNode().

*

*/

#include "Python.h"

#include "Python-ast.h"

#include "node.h"

#include "ast.h"

#include "token.h"

#include <assert.h>

static int validate_stmts(asdl_seq *);

static int validate_exprs(asdl_seq *, expr_context_ty, int);

static int validate_nonempty_seq(asdl_seq *, const char *, const char *);

static int validate_stmt(stmt_ty);

static int validate_expr(expr_ty, expr_context_ty);

static int

validate_comprehension(asdl_seq *gens)

{

int i;

if (!asdl_seq_LEN(gens)) {

PyErr_SetString(PyExc_ValueError, "comprehension with no generators");

return 0;

}

for (i = 0; i < asdl_seq_LEN(gens); i++) {

comprehension_ty comp = asdl_seq_GET(gens, i);

if (!validate_expr(comp->target, Store) ||

!validate_expr(comp->iter, Load) ||

!validate_exprs(comp->ifs, Load, 0))

return 0;

}

return 1;

}

static int

validate_slice(slice_ty slice)

{

switch (slice->kind) {

case Slice_kind:

return (!slice->v.Slice.lower || validate_expr(slice->v.Slice.lower, Load)) &&

(!slice->v.Slice.upper || validate_expr(slice->v.Slice.upper, Load)) &&

(!slice->v.Slice.step || validate_expr(slice->v.Slice.step, Load));

case ExtSlice_kind: {

int i;

if (!validate_nonempty_seq(slice->v.ExtSlice.dims, "dims", "ExtSlice"))

return 0;

for (i = 0; i < asdl_seq_LEN(slice->v.ExtSlice.dims); i++)

if (!validate_slice(asdl_seq_GET(slice->v.ExtSlice.dims, i)))

return 0;

return 1;

}

case Index_kind:

return validate_expr(slice->v.Index.value, Load);

default:

PyErr_SetString(PyExc_SystemError, "unknown slice node");

return 0;

}

}

static int

validate_keywords(asdl_seq *keywords)

{

int i;

for (i = 0; i < asdl_seq_LEN(keywords); i++)

if (!validate_expr(((keyword_ty)asdl_seq_GET(keywords, i))->value, Load))

return 0;

return 1;

}

static int

validate_args(asdl_seq *args)

{

int i;

for (i = 0; i < asdl_seq_LEN(args); i++) {

arg_ty arg = asdl_seq_GET(args, i);

if (arg->annotation && !validate_expr(arg->annotation, Load))

return 0;

}

return 1;

}

static const char *

expr_context_name(expr_context_ty ctx)

{

switch (ctx) {

case Load:

return "Load";

case Store:

return "Store";

case Del:

return "Del";

case AugLoad:

return "AugLoad";

case AugStore:

return "AugStore";

case Param:

return "Param";

default:

assert(0);

return "(unknown)";

}

}

static int

validate_arguments(arguments_ty args)

{

if (!validate_args(args->args))

return 0;

if (args->varargannotation) {

if (!args->vararg) {

PyErr_SetString(PyExc_ValueError, "varargannotation but no vararg on arguments");

return 0;

}

if (!validate_expr(args->varargannotation, Load))

return 0;

}

if (!validate_args(args->kwonlyargs))

return 0;

if (args->kwargannotation) {

if (!args->kwarg) {

PyErr_SetString(PyExc_ValueError, "kwargannotation but no kwarg on arguments");

return 0;

}

if (!validate_expr(args->kwargannotation, Load))

return 0;

}

if (asdl_seq_LEN(args->defaults) > asdl_seq_LEN(args->args)) {

PyErr_SetString(PyExc_ValueError, "more positional defaults than args on arguments");

return 0;

}

if (asdl_seq_LEN(args->kw_defaults) != asdl_seq_LEN(args->kwonlyargs)) {

PyErr_SetString(PyExc_ValueError, "length of kwonlyargs is not the same as "

"kw_defaults on arguments");

return 0;

}

return validate_exprs(args->defaults, Load, 0) && validate_exprs(args->kw_defaults, Load, 1);

}

static int

validate_expr(expr_ty exp, expr_context_ty ctx)

{

int check_ctx = 1;

expr_context_ty actual_ctx;

/* First check expression context. */

switch (exp->kind) {

case Attribute_kind:

actual_ctx = exp->v.Attribute.ctx;

break;

case Subscript_kind:

actual_ctx = exp->v.Subscript.ctx;

break;

case Starred_kind:

actual_ctx = exp->v.Starred.ctx;

break;

case Name_kind:

actual_ctx = exp->v.Name.ctx;

break;

case List_kind:

actual_ctx = exp->v.List.ctx;

break;

case Tuple_kind:

actual_ctx = exp->v.Tuple.ctx;

break;

default:

if (ctx != Load) {

PyErr_Format(PyExc_ValueError, "expression which can't be "

"assigned to in %s context", expr_context_name(ctx));

return 0;

}

check_ctx = 0;

}

if (check_ctx && actual_ctx != ctx) {

PyErr_Format(PyExc_ValueError, "expression must have %s context but has %s instead",

expr_context_name(ctx), expr_context_name(actual_ctx));

return 0;

}

/* Now validate expression. */

switch (exp->kind) {

case BoolOp_kind:

if (asdl_seq_LEN(exp->v.BoolOp.values) < 2) {

PyErr_SetString(PyExc_ValueError, "BoolOp with less than 2 values");

return 0;

}

return validate_exprs(exp->v.BoolOp.values, Load, 0);

case BinOp_kind:

return validate_expr(exp->v.BinOp.left, Load) &&

validate_expr(exp->v.BinOp.right, Load);

case UnaryOp_kind:

return validate_expr(exp->v.UnaryOp.operand, Load);

case Lambda_kind:

return validate_arguments(exp->v.Lambda.args) &&

validate_expr(exp->v.Lambda.body, Load);

case IfExp_kind:

return validate_expr(exp->v.IfExp.test, Load) &&

validate_expr(exp->v.IfExp.body, Load) &&

validate_expr(exp->v.IfExp.orelse, Load);

case Dict_kind:

if (asdl_seq_LEN(exp->v.Dict.keys) != asdl_seq_LEN(exp->v.Dict.values)) {

PyErr_SetString(PyExc_ValueError,

"Dict doesn't have the same number of keys as values");

return 0;

}

return validate_exprs(exp->v.Dict.keys, Load, 0) &&

validate_exprs(exp->v.Dict.values, Load, 0);

case Set_kind:

return validate_exprs(exp->v.Set.elts, Load, 0);

#define COMP(NAME) \

case NAME ## _kind: \

return validate_comprehension(exp->v.NAME.generators) && \

validate_expr(exp->v.NAME.elt, Load);

COMP(ListComp)

COMP(SetComp)

COMP(GeneratorExp)

#undef COMP

case DictComp_kind:

return validate_comprehension(exp->v.DictComp.generators) &&

validate_expr(exp->v.DictComp.key, Load) &&

validate_expr(exp->v.DictComp.value, Load);

case Yield_kind:

return !exp->v.Yield.value || validate_expr(exp->v.Yield.value, Load);

case YieldFrom_kind:

return !exp->v.YieldFrom.value ||

validate_expr(exp->v.YieldFrom.value, Load);

case Compare_kind:

if (!asdl_seq_LEN(exp->v.Compare.comparators)) {

PyErr_SetString(PyExc_ValueError, "Compare with no comparators");

return 0;

}

if (asdl_seq_LEN(exp->v.Compare.comparators) !=

asdl_seq_LEN(exp->v.Compare.ops)) {

PyErr_SetString(PyExc_ValueError, "Compare has a different number "

"of comparators and operands");

return 0;

}

return validate_exprs(exp->v.Compare.comparators, Load, 0) &&

validate_expr(exp->v.Compare.left, Load);

case Call_kind:

return validate_expr(exp->v.Call.func, Load) &&

validate_exprs(exp->v.Call.args, Load, 0) &&

validate_keywords(exp->v.Call.keywords) &&

(!exp->v.Call.starargs || validate_expr(exp->v.Call.starargs, Load)) &&

(!exp->v.Call.kwargs || validate_expr(exp->v.Call.kwargs, Load));

case Num_kind: {

PyObject *n = exp->v.Num.n;

if (!PyLong_CheckExact(n) && !PyFloat_CheckExact(n) &&

!PyComplex_CheckExact(n)) {

PyErr_SetString(PyExc_TypeError, "non-numeric type in Num");

return 0;

}

return 1;

}

case Str_kind: {

PyObject *s = exp->v.Str.s;

if (!PyUnicode_CheckExact(s)) {

PyErr_SetString(PyExc_TypeError, "non-string type in Str");

return 0;

}

return 1;

}

case Bytes_kind: {

PyObject *b = exp->v.Bytes.s;

if (!PyBytes_CheckExact(b)) {

PyErr_SetString(PyExc_TypeError, "non-bytes type in Bytes");

return 0;

}

return 1;

}

case Attribute_kind:

return validate_expr(exp->v.Attribute.value, Load);

case Subscript_kind:

return validate_slice(exp->v.Subscript.slice) &&

validate_expr(exp->v.Subscript.value, Load);

case Starred_kind:

return validate_expr(exp->v.Starred.value, ctx);

case List_kind:

return validate_exprs(exp->v.List.elts, ctx, 0);

case Tuple_kind:

return validate_exprs(exp->v.Tuple.elts, ctx, 0);

/* These last cases don't have any checking. */

case Name_kind:

case Ellipsis_kind:

return 1;

default:

PyErr_SetString(PyExc_SystemError, "unexpected expression");

return 0;

}

}

static int

validate_nonempty_seq(asdl_seq *seq, const char *what, const char *owner)

{

if (asdl_seq_LEN(seq))

return 1;

PyErr_Format(PyExc_ValueError, "empty %s on %s", what, owner);

return 0;

}

static int

validate_assignlist(asdl_seq *targets, expr_context_ty ctx)

{

return validate_nonempty_seq(targets, "targets", ctx == Del ? "Delete" : "Assign") &&

validate_exprs(targets, ctx, 0);

}

static int

validate_body(asdl_seq *body, const char *owner)

{

return validate_nonempty_seq(body, "body", owner) && validate_stmts(body);

}

static int

validate_stmt(stmt_ty stmt)

{

int i;

switch (stmt->kind) {

case FunctionDef_kind:

return validate_body(stmt->v.FunctionDef.body, "FunctionDef") &&

validate_arguments(stmt->v.FunctionDef.args) &&

validate_exprs(stmt->v.FunctionDef.decorator_list, Load, 0) &&

(!stmt->v.FunctionDef.returns ||

validate_expr(stmt->v.FunctionDef.returns, Load));

case ClassDef_kind:

return validate_body(stmt->v.ClassDef.body, "ClassDef") &&

validate_exprs(stmt->v.ClassDef.bases, Load, 0) &&

validate_keywords(stmt->v.ClassDef.keywords) &&

validate_exprs(stmt->v.ClassDef.decorator_list, Load, 0) &&

(!stmt->v.ClassDef.starargs || validate_expr(stmt->v.ClassDef.starargs, Load)) &&

(!stmt->v.ClassDef.kwargs || validate_expr(stmt->v.ClassDef.kwargs, Load));

case Return_kind:

return !stmt->v.Return.value || validate_expr(stmt->v.Return.value, Load);

case Delete_kind:

return validate_assignlist(stmt->v.Delete.targets, Del);

case Assign_kind:

return validate_assignlist(stmt->v.Assign.targets, Store) &&

validate_expr(stmt->v.Assign.value, Load);

case AugAssign_kind:

return validate_expr(stmt->v.AugAssign.target, Store) &&

validate_expr(stmt->v.AugAssign.value, Load);

case For_kind:

return validate_expr(stmt->v.For.target, Store) &&

validate_expr(stmt->v.For.iter, Load) &&

validate_body(stmt->v.For.body, "For") &&

validate_stmts(stmt->v.For.orelse);

case While_kind:

return validate_expr(stmt->v.While.test, Load) &&

validate_body(stmt->v.While.body, "While") &&

validate_stmts(stmt->v.While.orelse);

case If_kind:

return validate_expr(stmt->v.If.test, Load) &&

validate_body(stmt->v.If.body, "If") &&

validate_stmts(stmt->v.If.orelse);

case With_kind:

if (!validate_nonempty_seq(stmt->v.With.items, "items", "With"))

return 0;

for (i = 0; i < asdl_seq_LEN(stmt->v.With.items); i++) {

withitem_ty item = asdl_seq_GET(stmt->v.With.items, i);

if (!validate_expr(item->context_expr, Load) ||

(item->optional_vars && !validate_expr(item->optional_vars, Store)))

return 0;

}

return validate_body(stmt->v.With.body, "With");

case Raise_kind:

if (stmt->v.Raise.exc) {

return validate_expr(stmt->v.Raise.exc, Load) &&

(!stmt->v.Raise.cause || validate_expr(stmt->v.Raise.cause, Load));

}

if (stmt->v.Raise.cause) {

PyErr_SetString(PyExc_ValueError, "Raise with cause but no exception");

return 0;

}

return 1;

case Try_kind:

if (!validate_body(stmt->v.Try.body, "Try"))

return 0;

if (!asdl_seq_LEN(stmt->v.Try.handlers) &&

!asdl_seq_LEN(stmt->v.Try.finalbody)) {

PyErr_SetString(PyExc_ValueError, "Try has neither except handlers nor finalbody");

return 0;

}

if (!asdl_seq_LEN(stmt->v.Try.handlers) &&

asdl_seq_LEN(stmt->v.Try.orelse)) {

PyErr_SetString(PyExc_ValueError, "Try has orelse but no except handlers");

return 0;

}

for (i = 0; i < asdl_seq_LEN(stmt->v.Try.handlers); i++) {

excepthandler_ty handler = asdl_seq_GET(stmt->v.Try.handlers, i);

if ((handler->v.ExceptHandler.type &&

!validate_expr(handler->v.ExceptHandler.type, Load)) ||

!validate_body(handler->v.ExceptHandler.body, "ExceptHandler"))

return 0;

}

return (!asdl_seq_LEN(stmt->v.Try.finalbody) ||

validate_stmts(stmt->v.Try.finalbody)) &&

(!asdl_seq_LEN(stmt->v.Try.orelse) ||

validate_stmts(stmt->v.Try.orelse));

case Assert_kind:

return validate_expr(stmt->v.Assert.test, Load) &&

(!stmt->v.Assert.msg || validate_expr(stmt->v.Assert.msg, Load));

case Import_kind:

return validate_nonempty_seq(stmt->v.Import.names, "names", "Import");

case ImportFrom_kind:

if (stmt->v.ImportFrom.level < -1) {

PyErr_SetString(PyExc_ValueError, "ImportFrom level less than -1");

return 0;

}

return validate_nonempty_seq(stmt->v.ImportFrom.names, "names", "ImportFrom");

case Global_kind:

return validate_nonempty_seq(stmt->v.Global.names, "names", "Global");

case Nonlocal_kind:

return validate_nonempty_seq(stmt->v.Nonlocal.names, "names", "Nonlocal");

case Expr_kind:

return validate_expr(stmt->v.Expr.value, Load);

case Pass_kind:

case Break_kind:

case Continue_kind:

return 1;

default:

PyErr_SetString(PyExc_SystemError, "unexpected statement");

return 0;

}

}

static int

validate_stmts(asdl_seq *seq)

{

int i;

for (i = 0; i < asdl_seq_LEN(seq); i++) {

stmt_ty stmt = asdl_seq_GET(seq, i);

if (stmt) {

if (!validate_stmt(stmt))

return 0;

}

else {

PyErr_SetString(PyExc_ValueError,

"None disallowed in statement list");

return 0;

}

}

return 1;

}

static int

validate_exprs(asdl_seq *exprs, expr_context_ty ctx, int null_ok)

{

int i;

for (i = 0; i < asdl_seq_LEN(exprs); i++) {

expr_ty expr = asdl_seq_GET(exprs, i);

if (expr) {

if (!validate_expr(expr, ctx))

return 0;

}

else if (!null_ok) {

PyErr_SetString(PyExc_ValueError,

"None disallowed in expression list");

return 0;

}

}

return 1;

}

int

PyAST_Validate(mod_ty mod)

{

int res = 0;

switch (mod->kind) {

case Module_kind:

res = validate_stmts(mod->v.Module.body);

break;

case Interactive_kind:

res = validate_stmts(mod->v.Interactive.body);

break;

case Expression_kind:

res = validate_expr(mod->v.Expression.body, Load);

break;

case Suite_kind:

PyErr_SetString(PyExc_ValueError, "Suite is not valid in the CPython compiler");

break;

default:

PyErr_SetString(PyExc_SystemError, "impossible module node");

res = 0;

break;

}

return res;

}

/* This is done here, so defines like "test" don't interfere with AST use above. */

#include "grammar.h"

#include "parsetok.h"

#include "graminit.h"

/* Data structure used internally */

struct compiling {

char *c_encoding; /* source encoding */

PyArena *c_arena; /* arena for allocating memeory */

const char *c_filename; /* filename */

};

static asdl_seq *seq_for_testlist(struct compiling *, const node *);

static expr_ty ast_for_expr(struct compiling *, const node *);

static stmt_ty ast_for_stmt(struct compiling *, const node *);

static asdl_seq *ast_for_suite(struct compiling *, const node *);

static asdl_seq *ast_for_exprlist(struct compiling *, const node *,

expr_context_ty);

static expr_ty ast_for_testlist(struct compiling *, const node *);

static stmt_ty ast_for_classdef(struct compiling *, const node *, asdl_seq *);

/* Note different signature for ast_for_call */

static expr_ty ast_for_call(struct compiling *, const node *, expr_ty);

static PyObject *parsenumber(struct compiling *, const char *);

static PyObject *parsestr(struct compiling *, const node *n, int *bytesmode);

static PyObject *parsestrplus(struct compiling *, const node *n,

int *bytesmode);

#ifndef LINENO

#define LINENO(n) ((n)->n_lineno)

#endif

#define COMP_GENEXP 0

#define COMP_LISTCOMP 1

#define COMP_SETCOMP 2

static identifier

new_identifier(const char* n, PyArena *arena)

{

_Py_IDENTIFIER(normalize);

PyObject* id = PyUnicode_DecodeUTF8(n, strlen(n), NULL);

if (!id)

return NULL;

assert(PyUnicode_IS_READY(id));

/* Check whether there are non-ASCII characters in the

identifier; if so, normalize to NFKC. */

if (!PyUnicode_IS_ASCII(id)) {

PyObject *m = PyImport_ImportModuleNoBlock("unicodedata");

PyObject *id2;

if (!m) {

Py_DECREF(id);

return NULL;

}

id2 = _PyObject_CallMethodId(m, &PyId_normalize, "sO", "NFKC", id);

Py_DECREF(m);

Py_DECREF(id);

if (!id2)

return NULL;

id = id2;

}

PyUnicode_InternInPlace(&id);

PyArena_AddPyObject(arena, id);

return id;

}

#define NEW_IDENTIFIER(n) new_identifier(STR(n), c->c_arena)

/* This routine provides an invalid object for the syntax error.

The outermost routine must unpack this error and create the

proper object. We do this so that we don't have to pass

the filename to everything function.

XXX Maybe we should just pass the filename...

*/

static int

ast_error(const node *n, const char *errstr)

{

PyObject *u = Py_BuildValue("zii", errstr, LINENO(n), n->n_col_offset);

if (!u)

return 0;

PyErr_SetObject(PyExc_SyntaxError, u);

Py_DECREF(u);

return 0;

}

static void

ast_error_finish(const char *filename)

{

PyObject *type, *value, *tback, *errstr, *offset, *loc, *tmp;

PyObject *filename_obj;

long lineno;

assert(PyErr_Occurred());

if (!PyErr_ExceptionMatches(PyExc_SyntaxError))

return;

PyErr_Fetch(&type, &value, &tback);

errstr = PyTuple_GetItem(value, 0);

if (!errstr)

return;

Py_INCREF(errstr);

lineno = PyLong_AsLong(PyTuple_GetItem(value, 1));

if (lineno == -1) {

Py_DECREF(errstr);

return;

}

offset = PyTuple_GetItem(value, 2);

if (!offset) {

Py_DECREF(errstr);

return;

}

Py_DECREF(value);

loc = PyErr_ProgramText(filename, lineno);

if (!loc) {

Py_INCREF(Py_None);

loc = Py_None;

}

if (filename != NULL)

filename_obj = PyUnicode_DecodeFSDefault(filename);

else {

Py_INCREF(Py_None);

filename_obj = Py_None;

}

if (filename_obj != NULL)

tmp = Py_BuildValue("(NlOO)", filename_obj, lineno, offset, loc);

else

tmp = NULL;

Py_DECREF(loc);

if (!tmp) {

Py_DECREF(errstr);

return;

}

value = PyTuple_Pack(2, errstr, tmp);

Py_DECREF(errstr);

Py_DECREF(tmp);

if (!value)

return;

PyErr_Restore(type, value, tback);

}

/* num_stmts() returns number of contained statements.

Use this routine to determine how big a sequence is needed for

the statements in a parse tree. Its raison d'etre is this bit of

grammar:

stmt: simple_stmt | compound_stmt

simple_stmt: small_stmt (';' small_stmt)* [';'] NEWLINE

A simple_stmt can contain multiple small_stmt elements joined

by semicolons. If the arg is a simple_stmt, the number of

small_stmt elements is returned.

*/

static int

num_stmts(const node *n)

{

int i, l;

node *ch;

switch (TYPE(n)) {

case single_input:

if (TYPE(CHILD(n, 0)) == NEWLINE)

return 0;

else

return num_stmts(CHILD(n, 0));

case file_input:

l = 0;

for (i = 0; i < NCH(n); i++) {

ch = CHILD(n, i);

if (TYPE(ch) == stmt)

l += num_stmts(ch);

}

return l;

case stmt:

return num_stmts(CHILD(n, 0));

case compound_stmt:

return 1;

case simple_stmt:

return NCH(n) / 2; /* Divide by 2 to remove count of semi-colons */

case suite:

if (NCH(n) == 1)

return num_stmts(CHILD(n, 0));

else {

l = 0;

for (i = 2; i < (NCH(n) - 1); i++)

l += num_stmts(CHILD(n, i));

return l;

}

default: {

char buf[128];

sprintf(buf, "Non-statement found: %d %d",

TYPE(n), NCH(n));

Py_FatalError(buf);

}

}

assert(0);

return 0;

}

/* Transform the CST rooted at node * to the appropriate AST

*/

mod_ty

PyAST_FromNode(const node *n, PyCompilerFlags *flags, const char *filename,

PyArena *arena)

{

int i, j, k, num;

asdl_seq *stmts = NULL;

stmt_ty s;

node *ch;

struct compiling c;

if (flags && flags->cf_flags & PyCF_SOURCE_IS_UTF8) {

c.c_encoding = "utf-8";

if (TYPE(n) == encoding_decl) {

#if 0

ast_error(n, "encoding declaration in Unicode string");

goto error;

#endif

n = CHILD(n, 0);

}

} else if (TYPE(n) == encoding_decl) {

c.c_encoding = STR(n);

n = CHILD(n, 0);

} else {

/* PEP 3120 */

c.c_encoding = "utf-8";

}

c.c_arena = arena;

c.c_filename = filename;

k = 0;

switch (TYPE(n)) {

case file_input:

stmts = asdl_seq_new(num_stmts(n), arena);

if (!stmts)

return NULL;

for (i = 0; i < NCH(n) - 1; i++) {

ch = CHILD(n, i);

if (TYPE(ch) == NEWLINE)

continue;

REQ(ch, stmt);

num = num_stmts(ch);

if (num == 1) {

s = ast_for_stmt(&c, ch);

if (!s)

goto error;

asdl_seq_SET(stmts, k++, s);

}

else {

ch = CHILD(ch, 0);

REQ(ch, simple_stmt);

for (j = 0; j < num; j++) {

s = ast_for_stmt(&c, CHILD(ch, j * 2));

if (!s)

goto error;

asdl_seq_SET(stmts, k++, s);

}

}

}

return Module(stmts, arena);

case eval_input: {

expr_ty testlist_ast;

/* XXX Why not comp_for here? */

testlist_ast = ast_for_testlist(&c, CHILD(n, 0));

if (!testlist_ast)

goto error;

return Expression(testlist_ast, arena);

}

case single_input:

if (TYPE(CHILD(n, 0)) == NEWLINE) {

stmts = asdl_seq_new(1, arena);

if (!stmts)

goto error;

asdl_seq_SET(stmts, 0, Pass(n->n_lineno, n->n_col_offset,

arena));

if (!asdl_seq_GET(stmts, 0))

goto error;

return Interactive(stmts, arena);

}

else {

n = CHILD(n, 0);

num = num_stmts(n);

stmts = asdl_seq_new(num, arena);

if (!stmts)

goto error;

if (num == 1) {

s = ast_for_stmt(&c, n);

if (!s)

goto error;

asdl_seq_SET(stmts, 0, s);

}

else {

/* Only a simple_stmt can contain multiple statements. */

REQ(n, simple_stmt);

for (i = 0; i < NCH(n); i += 2) {

if (TYPE(CHILD(n, i)) == NEWLINE)

break;

s = ast_for_stmt(&c, CHILD(n, i));

if (!s)

goto error;

asdl_seq_SET(stmts, i / 2, s);

}

}

return Interactive(stmts, arena);

}

default:

PyErr_Format(PyExc_SystemError,

"invalid node %d for PyAST_FromNode", TYPE(n));

goto error;

}

error:

ast_error_finish(filename);

return NULL;

}

/* Return the AST repr. of the operator represented as syntax (|, ^, etc.)

*/

static operator_ty

get_operator(const node *n)

{

switch (TYPE(n)) {

case VBAR:

return BitOr;

case CIRCUMFLEX:

return BitXor;

case AMPER:

return BitAnd;

case LEFTSHIFT:

return LShift;

case RIGHTSHIFT:

return RShift;

case PLUS:

return Add;

case MINUS:

return Sub;

case STAR:

return Mult;

case SLASH:

return Div;

case DOUBLESLASH:

return FloorDiv;

case PERCENT:

return Mod;

default:

return (operator_ty)0;

}

}

static const char* FORBIDDEN[] = {

"None",

"True",

"False",

NULL,

};

static int

forbidden_name(identifier name, const node *n, int full_checks)

{

assert(PyUnicode_Check(name));

if (PyUnicode_CompareWithASCIIString(name, "__debug__") == 0) {

ast_error(n, "assignment to keyword");

return 1;

}

if (full_checks) {

const char **p;

for (p = FORBIDDEN; *p; p++) {

if (PyUnicode_CompareWithASCIIString(name, *p) == 0) {

ast_error(n, "assignment to keyword");

return 1;

}

}

}

return 0;

}

/* Set the context ctx for expr_ty e, recursively traversing e.

Only sets context for expr kinds that "can appear in assignment context"

(according to ../Parser/Python.asdl). For other expr kinds, it sets

an appropriate syntax error and returns false.

*/

static int

set_context(struct compiling *c, expr_ty e, expr_context_ty ctx, const node *n)

{

asdl_seq *s = NULL;

/* If a particular expression type can't be used for assign / delete,

set expr_name to its name and an error message will be generated.

*/

const char* expr_name = NULL;

/* The ast defines augmented store and load contexts, but the

implementation here doesn't actually use them. The code may be

a little more complex than necessary as a result. It also means

that expressions in an augmented assignment have a Store context.

Consider restructuring so that augmented assignment uses

set_context(), too.

*/

assert(ctx != AugStore && ctx != AugLoad);

switch (e->kind) {

case Attribute_kind:

e->v.Attribute.ctx = ctx;

if (ctx == Store && forbidden_name(e->v.Attribute.attr, n, 1))

return 0;

break;

case Subscript_kind:

e->v.Subscript.ctx = ctx;

break;

case Starred_kind:

e->v.Starred.ctx = ctx;

if (!set_context(c, e->v.Starred.value, ctx, n))

return 0;

break;

case Name_kind:

if (ctx == Store) {

if (forbidden_name(e->v.Name.id, n, 1))

return 0; /* forbidden_name() calls ast_error() */

}

e->v.Name.ctx = ctx;

break;

case List_kind:

e->v.List.ctx = ctx;

s = e->v.List.elts;

break;

case Tuple_kind:

if (asdl_seq_LEN(e->v.Tuple.elts)) {

e->v.Tuple.ctx = ctx;

s = e->v.Tuple.elts;

}

else {

expr_name = "()";

}

break;

case Lambda_kind:

expr_name = "lambda";

break;

case Call_kind:

expr_name = "function call";

break;

case BoolOp_kind:

case BinOp_kind:

case UnaryOp_kind:

expr_name = "operator";

break;

case GeneratorExp_kind:

expr_name = "generator expression";

break;

case Yield_kind:

case YieldFrom_kind:

expr_name = "yield expression";

break;

case ListComp_kind:

expr_name = "list comprehension";

break;

case SetComp_kind:

expr_name = "set comprehension";

break;

case DictComp_kind:

expr_name = "dict comprehension";

break;

case Dict_kind:

case Set_kind:

case Num_kind:

case Str_kind:

case Bytes_kind:

expr_name = "literal";

break;

case Ellipsis_kind:

expr_name = "Ellipsis";

break;

case Compare_kind:

expr_name = "comparison";

break;

case IfExp_kind:

expr_name = "conditional expression";

break;

default:

PyErr_Format(PyExc_SystemError,

"unexpected expression in assignment %d (line %d)",

e->kind, e->lineno);

return 0;

}

/* Check for error string set by switch */

if (expr_name) {

char buf[300];

PyOS_snprintf(buf, sizeof(buf),

"can't %s %s",

ctx == Store ? "assign to" : "delete",

expr_name);

return ast_error(n, buf);

}

/* If the LHS is a list or tuple, we need to set the assignment

context for all the contained elements.

*/

if (s) {

int i;