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#2505: allow easier creation of AST nodes.

This commit is contained in:
Georg Brandl 2008-03-30 07:01:47 +00:00
parent c87c5800e7
commit c52ed59473
3 changed files with 238 additions and 32 deletions
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27
Doc/library/_ast.rst
View File

@ -46,9 +46,32 @@ node. The utf8 offset is recorded because the parser uses utf8 internally.
If these attributes are marked as optional in the grammar (using a question
mark), the value might be ``None``. If the attributes can have zero-or-more
values (marked with an asterisk), the values are represented as Python lists.
All possible attributes must be present and have valid values when compiling an
AST with :func:`compile`.
The constructor of a class ``_ast.T`` parses their arguments as follows:
* If there are positional arguments, there must be as many as there are items in
``T._fields``; they will be assigned as attributes of these names.
* If there are keyword arguments, they will set the attributes of the same names
to the given values.
For example, to create and populate a ``UnaryOp`` node, you could use ::
node = _ast.UnaryOp()
node.op = _ast.USub()
node.operand = _ast.Num()
node.operand.n = 5
node.operand.lineno = 0
node.operand.col_offset = 0
node.lineno = 0
node.col_offset = 0
or the more compact ::
node = _ast.UnaryOp(_ast.USub(), _ast.Num(5, lineno=0, col_offset=0),
lineno=0, col_offset=0)
The constructors of all ``_ast`` classes don't take arguments; instead, if you
create instances, you must assign the required attributes separately.
Abstract Grammar

108
Parser/asdl_c.py
View File

@ -578,6 +578,98 @@ class PyTypesVisitor(PickleVisitor):
def visitModule(self, mod):
self.emit("""
static int
ast_type_init(PyObject *self, PyObject *args, PyObject *kw)
{
Py_ssize_t i, numfields = 0;
int res = -1;
PyObject *key, *value, *fields;
fields = PyObject_GetAttrString((PyObject*)Py_TYPE(self), "_fields");
if (!fields)
PyErr_Clear();
if (fields) {
numfields = PySequence_Size(fields);
if (numfields == -1)
goto cleanup;
}
res = 0; /* if no error occurs, this stays 0 to the end */
if (PyTuple_GET_SIZE(args) > 0) {
if (numfields != PyTuple_GET_SIZE(args)) {
PyErr_Format(PyExc_TypeError, "%.400s constructor takes either 0 or "
"%d positional argument%s", Py_TYPE(self)->tp_name,
numfields, numfields == 1 ? "" : "s");
res = -1;
goto cleanup;
}
for (i = 0; i < PyTuple_GET_SIZE(args); i++) {
/* cannot be reached when fields is NULL */
PyObject *name = PySequence_GetItem(fields, i);
if (!name) {
res = -1;
goto cleanup;
}
res = PyObject_SetAttr(self, name, PyTuple_GET_ITEM(args, i));
Py_DECREF(name);
if (res < 0)
goto cleanup;
}
}
if (kw) {
i = 0; /* needed by PyDict_Next */
while (PyDict_Next(kw, &i, &key, &value)) {
res = PyObject_SetAttr(self, key, value);
if (res < 0)
goto cleanup;
}
}
cleanup:
Py_XDECREF(fields);
return res;
}
static PyTypeObject AST_type = {
PyVarObject_HEAD_INIT(&PyType_Type, 0)
"AST",
sizeof(PyObject),
0,
0, /* tp_dealloc */
0, /* tp_print */
0, /* tp_getattr */
0, /* tp_setattr */
0, /* tp_compare */
0, /* tp_repr */
0, /* tp_as_number */
0, /* tp_as_sequence */
0, /* tp_as_mapping */
0, /* tp_hash */
0, /* tp_call */
0, /* tp_str */
PyObject_GenericGetAttr, /* tp_getattro */
PyObject_GenericSetAttr, /* tp_setattro */
0, /* tp_as_buffer */
Py_TPFLAGS_DEFAULT | Py_TPFLAGS_BASETYPE, /* tp_flags */
0, /* tp_doc */
0, /* tp_traverse */
0, /* tp_clear */
0, /* tp_richcompare */
0, /* tp_weaklistoffset */
0, /* tp_iter */
0, /* tp_iternext */
0, /* tp_methods */
0, /* tp_members */
0, /* tp_getset */
0, /* tp_base */
0, /* tp_dict */
0, /* tp_descr_get */
0, /* tp_descr_set */
0, /* tp_dictoffset */
(initproc)ast_type_init, /* tp_init */
PyType_GenericAlloc, /* tp_alloc */
PyType_GenericNew, /* tp_new */
PyObject_Del, /* tp_free */
};
static PyTypeObject* make_type(char *type, PyTypeObject* base, char**fields, int num_fields)
{
PyObject *fnames, *result;
@ -606,7 +698,7 @@ static PyTypeObject* make_type(char *type, PyTypeObject* base, char**fields, int
static int add_attributes(PyTypeObject* type, char**attrs, int num_fields)
{
int i, result;
PyObject *s, *l = PyList_New(num_fields);
PyObject *s, *l = PyTuple_New(num_fields);
if (!l) return 0;
for(i = 0; i < num_fields; i++) {
s = PyString_FromString(attrs[i]);
@ -614,7 +706,7 @@ static int add_attributes(PyTypeObject* type, char**attrs, int num_fields)
Py_DECREF(l);
return 0;
}
PyList_SET_ITEM(l, i, s);
PyTuple_SET_ITEM(l, i, s);
}
result = PyObject_SetAttrString((PyObject*)type, "_attributes", l) >= 0;
Py_DECREF(l);
@ -716,7 +808,6 @@ static int obj2ast_bool(PyObject* obj, bool* out, PyArena* arena)
self.emit("{", 0)
self.emit("static int initialized;", 1)
self.emit("if (initialized) return 1;", 1)
self.emit('AST_type = make_type("AST", &PyBaseObject_Type, NULL, 0);', 1)
for dfn in mod.dfns:
self.visit(dfn)
self.emit("initialized = 1;", 1)
@ -728,12 +819,13 @@ static int obj2ast_bool(PyObject* obj, bool* out, PyArena* arena)
fields = name.value+"_fields"
else:
fields = "NULL"
self.emit('%s_type = make_type("%s", AST_type, %s, %d);' %
self.emit('%s_type = make_type("%s", &AST_type, %s, %d);' %
(name, name, fields, len(prod.fields)), 1)
self.emit("if (!%s_type) return 0;" % name, 1)
def visitSum(self, sum, name):
self.emit('%s_type = make_type("%s", AST_type, NULL, 0);' % (name, name), 1)
self.emit('%s_type = make_type("%s", &AST_type, NULL, 0);' %
(name, name), 1)
self.emit("if (!%s_type) return 0;" % name, 1)
if sum.attributes:
self.emit("if (!add_attributes(%s_type, %s_attributes, %d)) return 0;" %
@ -772,7 +864,7 @@ class ASTModuleVisitor(PickleVisitor):
self.emit('m = Py_InitModule3("_ast", NULL, NULL);', 1)
self.emit("if (!m) return;", 1)
self.emit("d = PyModule_GetDict(m);", 1)
self.emit('if (PyDict_SetItemString(d, "AST", (PyObject*)AST_type) < 0) return;', 1)
self.emit('if (PyDict_SetItemString(d, "AST", (PyObject*)&AST_type) < 0) return;', 1)
self.emit('if (PyModule_AddIntConstant(m, "PyCF_ONLY_AST", PyCF_ONLY_AST) < 0)', 1)
self.emit("return;", 2)
# Value of version: "$Revision$"
@ -979,7 +1071,7 @@ mod_ty PyAST_obj2mod(PyObject* ast, PyArena* arena, int mode)
int PyAST_Check(PyObject* obj)
{
init_types();
return PyObject_IsInstance(obj, (PyObject*)AST_type);
return PyObject_IsInstance(obj, (PyObject*)&AST_type);
}
"""
@ -1035,7 +1127,7 @@ def main(srcfile):
print >> f, '#include "Python.h"'
print >> f, '#include "%s-ast.h"' % mod.name
print >> f
print >>f, "static PyTypeObject* AST_type;"
print >>f, "static PyTypeObject AST_type;"
v = ChainOfVisitors(
PyTypesDeclareVisitor(f),
PyTypesVisitor(f),

135
Python/Python-ast.c
View File

@ -2,7 +2,7 @@
/*
__version__ 60978.
__version__ 62047.
This module must be committed separately after each AST grammar change;
The __version__ number is set to the revision number of the commit
@ -12,7 +12,7 @@
#include "Python.h"
#include "Python-ast.h"
static PyTypeObject* AST_type;
static PyTypeObject AST_type;
static PyTypeObject *mod_type;
static PyObject* ast2obj_mod(void*);
static PyTypeObject *Module_type;
@ -369,6 +369,98 @@ static char *alias_fields[]={
};
static int
ast_type_init(PyObject *self, PyObject *args, PyObject *kw)
{
Py_ssize_t i, numfields = 0;
int res = -1;
PyObject *key, *value, *fields;
fields = PyObject_GetAttrString((PyObject*)Py_TYPE(self), "_fields");
if (!fields)
PyErr_Clear();
if (fields) {
numfields = PySequence_Size(fields);
if (numfields == -1)
goto cleanup;
}
res = 0; /* if no error occurs, this stays 0 to the end */
if (PyTuple_GET_SIZE(args) > 0) {
if (numfields != PyTuple_GET_SIZE(args)) {
PyErr_Format(PyExc_TypeError, "%.400s constructor takes either 0 or "
"%d positional argument%s", Py_TYPE(self)->tp_name,
numfields, numfields == 1 ? "" : "s");
res = -1;
goto cleanup;
}
for (i = 0; i < PyTuple_GET_SIZE(args); i++) {
/* cannot be reached when fields is NULL */
PyObject *name = PySequence_GetItem(fields, i);
if (!name) {
res = -1;
goto cleanup;
}
res = PyObject_SetAttr(self, name, PyTuple_GET_ITEM(args, i));
Py_DECREF(name);
if (res < 0)
goto cleanup;
}
}
if (kw) {
i = 0; /* needed by PyDict_Next */
while (PyDict_Next(kw, &i, &key, &value)) {
res = PyObject_SetAttr(self, key, value);
if (res < 0)
goto cleanup;
}
}
cleanup:
Py_XDECREF(fields);
return res;
}
static PyTypeObject AST_type = {
PyVarObject_HEAD_INIT(&PyType_Type, 0)
"AST",
sizeof(PyObject),
0,
0, /* tp_dealloc */
0, /* tp_print */
0, /* tp_getattr */
0, /* tp_setattr */
0, /* tp_compare */
0, /* tp_repr */
0, /* tp_as_number */
0, /* tp_as_sequence */
0, /* tp_as_mapping */
0, /* tp_hash */
0, /* tp_call */
0, /* tp_str */
PyObject_GenericGetAttr, /* tp_getattro */
PyObject_GenericSetAttr, /* tp_setattro */
0, /* tp_as_buffer */
Py_TPFLAGS_DEFAULT | Py_TPFLAGS_BASETYPE, /* tp_flags */
0, /* tp_doc */
0, /* tp_traverse */
0, /* tp_clear */
0, /* tp_richcompare */
0, /* tp_weaklistoffset */
0, /* tp_iter */
0, /* tp_iternext */
0, /* tp_methods */
0, /* tp_members */
0, /* tp_getset */
0, /* tp_base */
0, /* tp_dict */
0, /* tp_descr_get */
0, /* tp_descr_set */
0, /* tp_dictoffset */
(initproc)ast_type_init, /* tp_init */
PyType_GenericAlloc, /* tp_alloc */
PyType_GenericNew, /* tp_new */
PyObject_Del, /* tp_free */
};
static PyTypeObject* make_type(char *type, PyTypeObject* base, char**fields, int num_fields)
{
PyObject *fnames, *result;
@ -397,7 +489,7 @@ static PyTypeObject* make_type(char *type, PyTypeObject* base, char**fields, int
static int add_attributes(PyTypeObject* type, char**attrs, int num_fields)
{
int i, result;
PyObject *s, *l = PyList_New(num_fields);
PyObject *s, *l = PyTuple_New(num_fields);
if (!l) return 0;
for(i = 0; i < num_fields; i++) {
s = PyString_FromString(attrs[i]);
@ -405,7 +497,7 @@ static int add_attributes(PyTypeObject* type, char**attrs, int num_fields)
Py_DECREF(l);
return 0;
}
PyList_SET_ITEM(l, i, s);
PyTuple_SET_ITEM(l, i, s);
}
result = PyObject_SetAttrString((PyObject*)type, "_attributes", l) >= 0;
Py_DECREF(l);
@ -506,8 +598,7 @@ static int init_types(void)
{
static int initialized;
if (initialized) return 1;
AST_type = make_type("AST", &PyBaseObject_Type, NULL, 0);
mod_type = make_type("mod", AST_type, NULL, 0);
mod_type = make_type("mod", &AST_type, NULL, 0);
if (!mod_type) return 0;
if (!add_attributes(mod_type, NULL, 0)) return 0;
Module_type = make_type("Module", mod_type, Module_fields, 1);
@ -520,7 +611,7 @@ static int init_types(void)
if (!Expression_type) return 0;
Suite_type = make_type("Suite", mod_type, Suite_fields, 1);
if (!Suite_type) return 0;
stmt_type = make_type("stmt", AST_type, NULL, 0);
stmt_type = make_type("stmt", &AST_type, NULL, 0);
if (!stmt_type) return 0;
if (!add_attributes(stmt_type, stmt_attributes, 2)) return 0;
FunctionDef_type = make_type("FunctionDef", stmt_type,
@ -572,7 +663,7 @@ static int init_types(void)
if (!Break_type) return 0;
Continue_type = make_type("Continue", stmt_type, NULL, 0);
if (!Continue_type) return 0;
expr_type = make_type("expr", AST_type, NULL, 0);
expr_type = make_type("expr", &AST_type, NULL, 0);
if (!expr_type) return 0;
if (!add_attributes(expr_type, expr_attributes, 2)) return 0;
BoolOp_type = make_type("BoolOp", expr_type, BoolOp_fields, 2);
@ -614,7 +705,7 @@ static int init_types(void)
if (!List_type) return 0;
Tuple_type = make_type("Tuple", expr_type, Tuple_fields, 2);
if (!Tuple_type) return 0;
expr_context_type = make_type("expr_context", AST_type, NULL, 0);
expr_context_type = make_type("expr_context", &AST_type, NULL, 0);
if (!expr_context_type) return 0;
if (!add_attributes(expr_context_type, NULL, 0)) return 0;
Load_type = make_type("Load", expr_context_type, NULL, 0);
@ -641,7 +732,7 @@ static int init_types(void)
if (!Param_type) return 0;
Param_singleton = PyType_GenericNew(Param_type, NULL, NULL);
if (!Param_singleton) return 0;
slice_type = make_type("slice", AST_type, NULL, 0);
slice_type = make_type("slice", &AST_type, NULL, 0);
if (!slice_type) return 0;
if (!add_attributes(slice_type, NULL, 0)) return 0;
Ellipsis_type = make_type("Ellipsis", slice_type, NULL, 0);
@ -652,7 +743,7 @@ static int init_types(void)
if (!ExtSlice_type) return 0;
Index_type = make_type("Index", slice_type, Index_fields, 1);
if (!Index_type) return 0;
boolop_type = make_type("boolop", AST_type, NULL, 0);
boolop_type = make_type("boolop", &AST_type, NULL, 0);
if (!boolop_type) return 0;
if (!add_attributes(boolop_type, NULL, 0)) return 0;
And_type = make_type("And", boolop_type, NULL, 0);
@ -663,7 +754,7 @@ static int init_types(void)
if (!Or_type) return 0;
Or_singleton = PyType_GenericNew(Or_type, NULL, NULL);
if (!Or_singleton) return 0;
operator_type = make_type("operator", AST_type, NULL, 0);
operator_type = make_type("operator", &AST_type, NULL, 0);
if (!operator_type) return 0;
if (!add_attributes(operator_type, NULL, 0)) return 0;
Add_type = make_type("Add", operator_type, NULL, 0);
@ -714,7 +805,7 @@ static int init_types(void)
if (!FloorDiv_type) return 0;
FloorDiv_singleton = PyType_GenericNew(FloorDiv_type, NULL, NULL);
if (!FloorDiv_singleton) return 0;
unaryop_type = make_type("unaryop", AST_type, NULL, 0);
unaryop_type = make_type("unaryop", &AST_type, NULL, 0);
if (!unaryop_type) return 0;
if (!add_attributes(unaryop_type, NULL, 0)) return 0;
Invert_type = make_type("Invert", unaryop_type, NULL, 0);
@ -733,7 +824,7 @@ static int init_types(void)
if (!USub_type) return 0;
USub_singleton = PyType_GenericNew(USub_type, NULL, NULL);
if (!USub_singleton) return 0;
cmpop_type = make_type("cmpop", AST_type, NULL, 0);
cmpop_type = make_type("cmpop", &AST_type, NULL, 0);
if (!cmpop_type) return 0;
if (!add_attributes(cmpop_type, NULL, 0)) return 0;
Eq_type = make_type("Eq", cmpop_type, NULL, 0);
@ -776,21 +867,21 @@ static int init_types(void)
if (!NotIn_type) return 0;
NotIn_singleton = PyType_GenericNew(NotIn_type, NULL, NULL);
if (!NotIn_singleton) return 0;
comprehension_type = make_type("comprehension", AST_type,
comprehension_type = make_type("comprehension", &AST_type,
comprehension_fields, 3);
if (!comprehension_type) return 0;
excepthandler_type = make_type("excepthandler", AST_type, NULL, 0);
excepthandler_type = make_type("excepthandler", &AST_type, NULL, 0);
if (!excepthandler_type) return 0;
if (!add_attributes(excepthandler_type, excepthandler_attributes, 2))
return 0;
ExceptHandler_type = make_type("ExceptHandler", excepthandler_type,
ExceptHandler_fields, 3);
if (!ExceptHandler_type) return 0;
arguments_type = make_type("arguments", AST_type, arguments_fields, 4);
arguments_type = make_type("arguments", &AST_type, arguments_fields, 4);
if (!arguments_type) return 0;
keyword_type = make_type("keyword", AST_type, keyword_fields, 2);
keyword_type = make_type("keyword", &AST_type, keyword_fields, 2);
if (!keyword_type) return 0;
alias_type = make_type("alias", AST_type, alias_fields, 2);
alias_type = make_type("alias", &AST_type, alias_fields, 2);
if (!alias_type) return 0;
initialized = 1;
return 1;
@ -5816,10 +5907,10 @@ init_ast(void)
m = Py_InitModule3("_ast", NULL, NULL);
if (!m) return;
d = PyModule_GetDict(m);
if (PyDict_SetItemString(d, "AST", (PyObject*)AST_type) < 0) return;
if (PyDict_SetItemString(d, "AST", (PyObject*)&AST_type) < 0) return;
if (PyModule_AddIntConstant(m, "PyCF_ONLY_AST", PyCF_ONLY_AST) < 0)
return;
if (PyModule_AddStringConstant(m, "__version__", "60978") < 0)
if (PyModule_AddStringConstant(m, "__version__", "62047") < 0)
return;
if (PyDict_SetItemString(d, "mod", (PyObject*)mod_type) < 0) return;
if (PyDict_SetItemString(d, "Module", (PyObject*)Module_type) < 0)
@ -5997,7 +6088,7 @@ mod_ty PyAST_obj2mod(PyObject* ast, PyArena* arena, int mode)
int PyAST_Check(PyObject* obj)
{
init_types();
return PyObject_IsInstance(obj, (PyObject*)AST_type);
return PyObject_IsInstance(obj, (PyObject*)&AST_type);
}