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parsermodule.c
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2957 lines (2580 loc) · 86.1 KB
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/* parsermodule.c
*
* Copyright 1995-1996 by Fred L. Drake, Jr. and Virginia Polytechnic
* Institute and State University, Blacksburg, Virginia, USA.
* Portions copyright 1991-1995 by Stichting Mathematisch Centrum,
* Amsterdam, The Netherlands. Copying is permitted under the terms
* associated with the main Python distribution, with the additional
* restriction that this additional notice be included and maintained
* on all distributed copies.
*
* This module serves to replace the original parser module written
* by Guido. The functionality is not matched precisely, but the
* original may be implemented on top of this. This is desirable
* since the source of the text to be parsed is now divorced from
* this interface.
*
* Unlike the prior interface, the ability to give a parse tree
* produced by Python code as a tuple to the compiler is enabled by
* this module. See the documentation for more details.
*
* I've added some annotations that help with the lint code-checking
* program, but they're not complete by a long shot. The real errors
* that lint detects are gone, but there are still warnings with
* Py_[X]DECREF() and Py_[X]INCREF() macros. The lint annotations
* look like "NOTE(...)".
*/
#include "Python.h" /* general Python API */
#include "graminit.h" /* symbols defined in the grammar */
#include "node.h" /* internal parser structure */
#include "errcode.h" /* error codes for PyNode_*() */
#include "token.h" /* token definitions */
/* ISTERMINAL() / ISNONTERMINAL() */
#include "compile.h" /* PyNode_Compile() */
#ifdef lint
#include <note.h>
#else
#define NOTE(x)
#endif
#ifdef macintosh
char *strdup(char *);
#endif
/* String constants used to initialize module attributes.
*
*/
static char parser_copyright_string[] =
"Copyright 1995-1996 by Virginia Polytechnic Institute & State\n\
University, Blacksburg, Virginia, USA, and Fred L. Drake, Jr., Reston,\n\
Virginia, USA. Portions copyright 1991-1995 by Stichting Mathematisch\n\
Centrum, Amsterdam, The Netherlands.";
PyDoc_STRVAR(parser_doc_string,
"This is an interface to Python's internal parser.");
static char parser_version_string[] = "0.5";
typedef PyObject* (*SeqMaker) (int length);
typedef int (*SeqInserter) (PyObject* sequence,
int index,
PyObject* element);
/* The function below is copyrighted by Stichting Mathematisch Centrum. The
* original copyright statement is included below, and continues to apply
* in full to the function immediately following. All other material is
* original, copyrighted by Fred L. Drake, Jr. and Virginia Polytechnic
* Institute and State University. Changes were made to comply with the
* new naming conventions. Added arguments to provide support for creating
* lists as well as tuples, and optionally including the line numbers.
*/
static PyObject*
node2tuple(node *n, /* node to convert */
SeqMaker mkseq, /* create sequence */
SeqInserter addelem, /* func. to add elem. in seq. */
int lineno) /* include line numbers? */
{
if (n == NULL) {
Py_INCREF(Py_None);
return (Py_None);
}
if (ISNONTERMINAL(TYPE(n))) {
int i;
PyObject *v;
PyObject *w;
v = mkseq(1 + NCH(n) + (TYPE(n) == encoding_decl));
if (v == NULL)
return (v);
w = PyInt_FromLong(TYPE(n));
if (w == NULL) {
Py_DECREF(v);
return ((PyObject*) NULL);
}
(void) addelem(v, 0, w);
for (i = 0; i < NCH(n); i++) {
w = node2tuple(CHILD(n, i), mkseq, addelem, lineno);
if (w == NULL) {
Py_DECREF(v);
return ((PyObject*) NULL);
}
(void) addelem(v, i+1, w);
}
if (TYPE(n) == encoding_decl)
(void) addelem(v, i+1, PyString_FromString(STR(n)));
return (v);
}
else if (ISTERMINAL(TYPE(n))) {
PyObject *result = mkseq(2 + lineno);
if (result != NULL) {
(void) addelem(result, 0, PyInt_FromLong(TYPE(n)));
(void) addelem(result, 1, PyString_FromString(STR(n)));
if (lineno == 1)
(void) addelem(result, 2, PyInt_FromLong(n->n_lineno));
}
return (result);
}
else {
PyErr_SetString(PyExc_SystemError,
"unrecognized parse tree node type");
return ((PyObject*) NULL);
}
}
/*
* End of material copyrighted by Stichting Mathematisch Centrum.
*/
/* There are two types of intermediate objects we're interested in:
* 'eval' and 'exec' types. These constants can be used in the st_type
* field of the object type to identify which any given object represents.
* These should probably go in an external header to allow other extensions
* to use them, but then, we really should be using C++ too. ;-)
*/
#define PyST_EXPR 1
#define PyST_SUITE 2
/* These are the internal objects and definitions required to implement the
* ST type. Most of the internal names are more reminiscent of the 'old'
* naming style, but the code uses the new naming convention.
*/
static PyObject*
parser_error = 0;
typedef struct {
PyObject_HEAD /* standard object header */
node* st_node; /* the node* returned by the parser */
int st_type; /* EXPR or SUITE ? */
} PyST_Object;
static void parser_free(PyST_Object *st);
static int parser_compare(PyST_Object *left, PyST_Object *right);
static PyObject *parser_getattr(PyObject *self, char *name);
static
PyTypeObject PyST_Type = {
PyObject_HEAD_INIT(NULL)
0,
"parser.st", /* tp_name */
(int) sizeof(PyST_Object), /* tp_basicsize */
0, /* tp_itemsize */
(destructor)parser_free, /* tp_dealloc */
0, /* tp_print */
parser_getattr, /* tp_getattr */
0, /* tp_setattr */
(cmpfunc)parser_compare, /* 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 */
0, /* tp_getattro */
0, /* tp_setattro */
/* Functions to access object as input/output buffer */
0, /* tp_as_buffer */
Py_TPFLAGS_DEFAULT, /* tp_flags */
/* __doc__ */
"Intermediate representation of a Python parse tree."
}; /* PyST_Type */
static int
parser_compare_nodes(node *left, node *right)
{
int j;
if (TYPE(left) < TYPE(right))
return (-1);
if (TYPE(right) < TYPE(left))
return (1);
if (ISTERMINAL(TYPE(left)))
return (strcmp(STR(left), STR(right)));
if (NCH(left) < NCH(right))
return (-1);
if (NCH(right) < NCH(left))
return (1);
for (j = 0; j < NCH(left); ++j) {
int v = parser_compare_nodes(CHILD(left, j), CHILD(right, j));
if (v != 0)
return (v);
}
return (0);
}
/* int parser_compare(PyST_Object* left, PyST_Object* right)
*
* Comparison function used by the Python operators ==, !=, <, >, <=, >=
* This really just wraps a call to parser_compare_nodes() with some easy
* checks and protection code.
*
*/
static int
parser_compare(PyST_Object *left, PyST_Object *right)
{
if (left == right)
return (0);
if ((left == 0) || (right == 0))
return (-1);
return (parser_compare_nodes(left->st_node, right->st_node));
}
/* parser_newstobject(node* st)
*
* Allocates a new Python object representing an ST. This is simply the
* 'wrapper' object that holds a node* and allows it to be passed around in
* Python code.
*
*/
static PyObject*
parser_newstobject(node *st, int type)
{
PyST_Object* o = PyObject_New(PyST_Object, &PyST_Type);
if (o != 0) {
o->st_node = st;
o->st_type = type;
}
else {
PyNode_Free(st);
}
return ((PyObject*)o);
}
/* void parser_free(PyST_Object* st)
*
* This is called by a del statement that reduces the reference count to 0.
*
*/
static void
parser_free(PyST_Object *st)
{
PyNode_Free(st->st_node);
PyObject_Del(st);
}
/* parser_st2tuple(PyObject* self, PyObject* args, PyObject* kw)
*
* This provides conversion from a node* to a tuple object that can be
* returned to the Python-level caller. The ST object is not modified.
*
*/
static PyObject*
parser_st2tuple(PyST_Object *self, PyObject *args, PyObject *kw)
{
PyObject *line_option = 0;
PyObject *res = 0;
int ok;
static char *keywords[] = {"ast", "line_info", NULL};
if (self == NULL) {
ok = PyArg_ParseTupleAndKeywords(args, kw, "O!|O:st2tuple", keywords,
&PyST_Type, &self, &line_option);
}
else
ok = PyArg_ParseTupleAndKeywords(args, kw, "|O:totuple", &keywords[1],
&line_option);
if (ok != 0) {
int lineno = 0;
if (line_option != NULL) {
lineno = (PyObject_IsTrue(line_option) != 0) ? 1 : 0;
}
/*
* Convert ST into a tuple representation. Use Guido's function,
* since it's known to work already.
*/
res = node2tuple(((PyST_Object*)self)->st_node,
PyTuple_New, PyTuple_SetItem, lineno);
}
return (res);
}
/* parser_st2list(PyObject* self, PyObject* args, PyObject* kw)
*
* This provides conversion from a node* to a list object that can be
* returned to the Python-level caller. The ST object is not modified.
*
*/
static PyObject*
parser_st2list(PyST_Object *self, PyObject *args, PyObject *kw)
{
PyObject *line_option = 0;
PyObject *res = 0;
int ok;
static char *keywords[] = {"ast", "line_info", NULL};
if (self == NULL)
ok = PyArg_ParseTupleAndKeywords(args, kw, "O!|O:st2list", keywords,
&PyST_Type, &self, &line_option);
else
ok = PyArg_ParseTupleAndKeywords(args, kw, "|O:tolist", &keywords[1],
&line_option);
if (ok) {
int lineno = 0;
if (line_option != 0) {
lineno = PyObject_IsTrue(line_option) ? 1 : 0;
}
/*
* Convert ST into a tuple representation. Use Guido's function,
* since it's known to work already.
*/
res = node2tuple(self->st_node,
PyList_New, PyList_SetItem, lineno);
}
return (res);
}
/* parser_compilest(PyObject* self, PyObject* args)
*
* This function creates code objects from the parse tree represented by
* the passed-in data object. An optional file name is passed in as well.
*
*/
static PyObject*
parser_compilest(PyST_Object *self, PyObject *args, PyObject *kw)
{
PyObject* res = 0;
char* str = "<syntax-tree>";
int ok;
static char *keywords[] = {"ast", "filename", NULL};
if (self == NULL)
ok = PyArg_ParseTupleAndKeywords(args, kw, "O!|s:compilest", keywords,
&PyST_Type, &self, &str);
else
ok = PyArg_ParseTupleAndKeywords(args, kw, "|s:compile", &keywords[1],
&str);
if (ok)
res = (PyObject *)PyNode_Compile(self->st_node, str);
return (res);
}
/* PyObject* parser_isexpr(PyObject* self, PyObject* args)
* PyObject* parser_issuite(PyObject* self, PyObject* args)
*
* Checks the passed-in ST object to determine if it is an expression or
* a statement suite, respectively. The return is a Python truth value.
*
*/
static PyObject*
parser_isexpr(PyST_Object *self, PyObject *args, PyObject *kw)
{
PyObject* res = 0;
int ok;
static char *keywords[] = {"ast", NULL};
if (self == NULL)
ok = PyArg_ParseTupleAndKeywords(args, kw, "O!:isexpr", keywords,
&PyST_Type, &self);
else
ok = PyArg_ParseTupleAndKeywords(args, kw, ":isexpr", &keywords[1]);
if (ok) {
/* Check to see if the ST represents an expression or not. */
res = (self->st_type == PyST_EXPR) ? Py_True : Py_False;
Py_INCREF(res);
}
return (res);
}
static PyObject*
parser_issuite(PyST_Object *self, PyObject *args, PyObject *kw)
{
PyObject* res = 0;
int ok;
static char *keywords[] = {"ast", NULL};
if (self == NULL)
ok = PyArg_ParseTupleAndKeywords(args, kw, "O!:issuite", keywords,
&PyST_Type, &self);
else
ok = PyArg_ParseTupleAndKeywords(args, kw, ":issuite", &keywords[1]);
if (ok) {
/* Check to see if the ST represents an expression or not. */
res = (self->st_type == PyST_EXPR) ? Py_False : Py_True;
Py_INCREF(res);
}
return (res);
}
#define PUBLIC_METHOD_TYPE (METH_VARARGS|METH_KEYWORDS)
static PyMethodDef
parser_methods[] = {
{"compile", (PyCFunction)parser_compilest, PUBLIC_METHOD_TYPE,
PyDoc_STR("Compile this ST object into a code object.")},
{"isexpr", (PyCFunction)parser_isexpr, PUBLIC_METHOD_TYPE,
PyDoc_STR("Determines if this ST object was created from an expression.")},
{"issuite", (PyCFunction)parser_issuite, PUBLIC_METHOD_TYPE,
PyDoc_STR("Determines if this ST object was created from a suite.")},
{"tolist", (PyCFunction)parser_st2list, PUBLIC_METHOD_TYPE,
PyDoc_STR("Creates a list-tree representation of this ST.")},
{"totuple", (PyCFunction)parser_st2tuple, PUBLIC_METHOD_TYPE,
PyDoc_STR("Creates a tuple-tree representation of this ST.")},
{NULL, NULL, 0, NULL}
};
static PyObject*
parser_getattr(PyObject *self, char *name)
{
return (Py_FindMethod(parser_methods, self, name));
}
/* err_string(char* message)
*
* Sets the error string for an exception of type ParserError.
*
*/
static void
err_string(char *message)
{
PyErr_SetString(parser_error, message);
}
/* PyObject* parser_do_parse(PyObject* args, int type)
*
* Internal function to actually execute the parse and return the result if
* successful or set an exception if not.
*
*/
static PyObject*
parser_do_parse(PyObject *args, PyObject *kw, char *argspec, int type)
{
char* string = 0;
PyObject* res = 0;
static char *keywords[] = {"source", NULL};
if (PyArg_ParseTupleAndKeywords(args, kw, argspec, keywords, &string)) {
node* n = PyParser_SimpleParseString(string,
(type == PyST_EXPR)
? eval_input : file_input);
if (n)
res = parser_newstobject(n, type);
}
return (res);
}
/* PyObject* parser_expr(PyObject* self, PyObject* args)
* PyObject* parser_suite(PyObject* self, PyObject* args)
*
* External interfaces to the parser itself. Which is called determines if
* the parser attempts to recognize an expression ('eval' form) or statement
* suite ('exec' form). The real work is done by parser_do_parse() above.
*
*/
static PyObject*
parser_expr(PyST_Object *self, PyObject *args, PyObject *kw)
{
NOTE(ARGUNUSED(self))
return (parser_do_parse(args, kw, "s:expr", PyST_EXPR));
}
static PyObject*
parser_suite(PyST_Object *self, PyObject *args, PyObject *kw)
{
NOTE(ARGUNUSED(self))
return (parser_do_parse(args, kw, "s:suite", PyST_SUITE));
}
/* This is the messy part of the code. Conversion from a tuple to an ST
* object requires that the input tuple be valid without having to rely on
* catching an exception from the compiler. This is done to allow the
* compiler itself to remain fast, since most of its input will come from
* the parser directly, and therefore be known to be syntactically correct.
* This validation is done to ensure that we don't core dump the compile
* phase, returning an exception instead.
*
* Two aspects can be broken out in this code: creating a node tree from
* the tuple passed in, and verifying that it is indeed valid. It may be
* advantageous to expand the number of ST types to include funcdefs and
* lambdadefs to take advantage of the optimizer, recognizing those STs
* here. They are not necessary, and not quite as useful in a raw form.
* For now, let's get expressions and suites working reliably.
*/
static node* build_node_tree(PyObject *tuple);
static int validate_expr_tree(node *tree);
static int validate_file_input(node *tree);
static int validate_encoding_decl(node *tree);
/* PyObject* parser_tuple2st(PyObject* self, PyObject* args)
*
* This is the public function, called from the Python code. It receives a
* single tuple object from the caller, and creates an ST object if the
* tuple can be validated. It does this by checking the first code of the
* tuple, and, if acceptable, builds the internal representation. If this
* step succeeds, the internal representation is validated as fully as
* possible with the various validate_*() routines defined below.
*
* This function must be changed if support is to be added for PyST_FRAGMENT
* ST objects.
*
*/
static PyObject*
parser_tuple2st(PyST_Object *self, PyObject *args, PyObject *kw)
{
NOTE(ARGUNUSED(self))
PyObject *st = 0;
PyObject *tuple;
node *tree;
static char *keywords[] = {"sequence", NULL};
if (!PyArg_ParseTupleAndKeywords(args, kw, "O:sequence2st", keywords,
&tuple))
return (0);
if (!PySequence_Check(tuple)) {
PyErr_SetString(PyExc_ValueError,
"sequence2st() requires a single sequence argument");
return (0);
}
/*
* Convert the tree to the internal form before checking it.
*/
tree = build_node_tree(tuple);
if (tree != 0) {
int start_sym = TYPE(tree);
if (start_sym == eval_input) {
/* Might be an eval form. */
if (validate_expr_tree(tree))
st = parser_newstobject(tree, PyST_EXPR);
else
PyNode_Free(tree);
}
else if (start_sym == file_input) {
/* This looks like an exec form so far. */
if (validate_file_input(tree))
st = parser_newstobject(tree, PyST_SUITE);
else
PyNode_Free(tree);
}
else if (start_sym == encoding_decl) {
/* This looks like an encoding_decl so far. */
if (validate_encoding_decl(tree))
st = parser_newstobject(tree, PyST_SUITE);
else
PyNode_Free(tree);
}
else {
/* This is a fragment, at best. */
PyNode_Free(tree);
err_string("parse tree does not use a valid start symbol");
}
}
/* Make sure we throw an exception on all errors. We should never
* get this, but we'd do well to be sure something is done.
*/
if (st == NULL && !PyErr_Occurred())
err_string("unspecified ST error occurred");
return st;
}
/* node* build_node_children()
*
* Iterate across the children of the current non-terminal node and build
* their structures. If successful, return the root of this portion of
* the tree, otherwise, 0. Any required exception will be specified already,
* and no memory will have been deallocated.
*
*/
static node*
build_node_children(PyObject *tuple, node *root, int *line_num)
{
int len = PyObject_Size(tuple);
int i, err;
for (i = 1; i < len; ++i) {
/* elem must always be a sequence, however simple */
PyObject* elem = PySequence_GetItem(tuple, i);
int ok = elem != NULL;
long type = 0;
char *strn = 0;
if (ok)
ok = PySequence_Check(elem);
if (ok) {
PyObject *temp = PySequence_GetItem(elem, 0);
if (temp == NULL)
ok = 0;
else {
ok = PyInt_Check(temp);
if (ok)
type = PyInt_AS_LONG(temp);
Py_DECREF(temp);
}
}
if (!ok) {
PyErr_SetObject(parser_error,
Py_BuildValue("os", elem,
"Illegal node construct."));
Py_XDECREF(elem);
return (0);
}
if (ISTERMINAL(type)) {
int len = PyObject_Size(elem);
PyObject *temp;
if ((len != 2) && (len != 3)) {
err_string("terminal nodes must have 2 or 3 entries");
return 0;
}
temp = PySequence_GetItem(elem, 1);
if (temp == NULL)
return 0;
if (!PyString_Check(temp)) {
PyErr_Format(parser_error,
"second item in terminal node must be a string,"
" found %s",
temp->ob_type->tp_name);
Py_DECREF(temp);
return 0;
}
if (len == 3) {
PyObject *o = PySequence_GetItem(elem, 2);
if (o != NULL) {
if (PyInt_Check(o))
*line_num = PyInt_AS_LONG(o);
else {
PyErr_Format(parser_error,
"third item in terminal node must be an"
" integer, found %s",
temp->ob_type->tp_name);
Py_DECREF(o);
Py_DECREF(temp);
return 0;
}
Py_DECREF(o);
}
}
len = PyString_GET_SIZE(temp) + 1;
strn = (char *)PyMem_MALLOC(len);
if (strn != NULL)
(void) memcpy(strn, PyString_AS_STRING(temp), len);
Py_DECREF(temp);
}
else if (!ISNONTERMINAL(type)) {
/*
* It has to be one or the other; this is an error.
* Throw an exception.
*/
PyErr_SetObject(parser_error,
Py_BuildValue("os", elem, "unknown node type."));
Py_XDECREF(elem);
return (0);
}
err = PyNode_AddChild(root, type, strn, *line_num);
if (err == E_NOMEM) {
PyMem_DEL(strn);
return (node *) PyErr_NoMemory();
}
if (err == E_OVERFLOW) {
PyMem_DEL(strn);
PyErr_SetString(PyExc_ValueError,
"unsupported number of child nodes");
return NULL;
}
if (ISNONTERMINAL(type)) {
node* new_child = CHILD(root, i - 1);
if (new_child != build_node_children(elem, new_child, line_num)) {
Py_XDECREF(elem);
return (0);
}
}
else if (type == NEWLINE) { /* It's true: we increment the */
++(*line_num); /* line number *after* the newline! */
}
Py_XDECREF(elem);
}
return (root);
}
static node*
build_node_tree(PyObject *tuple)
{
node* res = 0;
PyObject *temp = PySequence_GetItem(tuple, 0);
long num = -1;
if (temp != NULL)
num = PyInt_AsLong(temp);
Py_XDECREF(temp);
if (ISTERMINAL(num)) {
/*
* The tuple is simple, but it doesn't start with a start symbol.
* Throw an exception now and be done with it.
*/
tuple = Py_BuildValue("os", tuple,
"Illegal syntax-tree; cannot start with terminal symbol.");
PyErr_SetObject(parser_error, tuple);
}
else if (ISNONTERMINAL(num)) {
/*
* Not efficient, but that can be handled later.
*/
int line_num = 0;
PyObject *encoding = NULL;
if (num == encoding_decl) {
encoding = PySequence_GetItem(tuple, 2);
/* tuple isn't borrowed anymore here, need to DECREF */
tuple = PySequence_GetSlice(tuple, 0, 2);
}
res = PyNode_New(num);
if (res != NULL) {
if (res != build_node_children(tuple, res, &line_num)) {
PyNode_Free(res);
res = NULL;
}
if (res && encoding) {
int len;
len = PyString_GET_SIZE(encoding) + 1;
res->n_str = (char *)PyMem_MALLOC(len);
if (res->n_str != NULL)
(void) memcpy(res->n_str, PyString_AS_STRING(encoding), len);
Py_DECREF(encoding);
Py_DECREF(tuple);
}
}
}
else
/* The tuple is illegal -- if the number is neither TERMINAL nor
* NONTERMINAL, we can't use it. Not sure the implementation
* allows this condition, but the API doesn't preclude it.
*/
PyErr_SetObject(parser_error,
Py_BuildValue("os", tuple,
"Illegal component tuple."));
return (res);
}
/*
* Validation routines used within the validation section:
*/
static int validate_terminal(node *terminal, int type, char *string);
#define validate_ampersand(ch) validate_terminal(ch, AMPER, "&")
#define validate_circumflex(ch) validate_terminal(ch, CIRCUMFLEX, "^")
#define validate_colon(ch) validate_terminal(ch, COLON, ":")
#define validate_comma(ch) validate_terminal(ch, COMMA, ",")
#define validate_dedent(ch) validate_terminal(ch, DEDENT, "")
#define validate_equal(ch) validate_terminal(ch, EQUAL, "=")
#define validate_indent(ch) validate_terminal(ch, INDENT, (char*)NULL)
#define validate_lparen(ch) validate_terminal(ch, LPAR, "(")
#define validate_newline(ch) validate_terminal(ch, NEWLINE, (char*)NULL)
#define validate_rparen(ch) validate_terminal(ch, RPAR, ")")
#define validate_semi(ch) validate_terminal(ch, SEMI, ";")
#define validate_star(ch) validate_terminal(ch, STAR, "*")
#define validate_vbar(ch) validate_terminal(ch, VBAR, "|")
#define validate_doublestar(ch) validate_terminal(ch, DOUBLESTAR, "**")
#define validate_dot(ch) validate_terminal(ch, DOT, ".")
#define validate_name(ch, str) validate_terminal(ch, NAME, str)
#define VALIDATER(n) static int validate_##n(node *tree)
VALIDATER(node); VALIDATER(small_stmt);
VALIDATER(class); VALIDATER(node);
VALIDATER(parameters); VALIDATER(suite);
VALIDATER(testlist); VALIDATER(varargslist);
VALIDATER(fpdef); VALIDATER(fplist);
VALIDATER(stmt); VALIDATER(simple_stmt);
VALIDATER(expr_stmt); VALIDATER(power);
VALIDATER(print_stmt); VALIDATER(del_stmt);
VALIDATER(return_stmt); VALIDATER(list_iter);
VALIDATER(raise_stmt); VALIDATER(import_stmt);
VALIDATER(global_stmt); VALIDATER(list_if);
VALIDATER(assert_stmt); VALIDATER(list_for);
VALIDATER(exec_stmt); VALIDATER(compound_stmt);
VALIDATER(while); VALIDATER(for);
VALIDATER(try); VALIDATER(except_clause);
VALIDATER(test); VALIDATER(and_test);
VALIDATER(not_test); VALIDATER(comparison);
VALIDATER(comp_op); VALIDATER(expr);
VALIDATER(xor_expr); VALIDATER(and_expr);
VALIDATER(shift_expr); VALIDATER(arith_expr);
VALIDATER(term); VALIDATER(factor);
VALIDATER(atom); VALIDATER(lambdef);
VALIDATER(trailer); VALIDATER(subscript);
VALIDATER(subscriptlist); VALIDATER(sliceop);
VALIDATER(exprlist); VALIDATER(dictmaker);
VALIDATER(arglist); VALIDATER(argument);
VALIDATER(listmaker); VALIDATER(yield_stmt);
VALIDATER(testlist1);
#undef VALIDATER
#define is_even(n) (((n) & 1) == 0)
#define is_odd(n) (((n) & 1) == 1)
static int
validate_ntype(node *n, int t)
{
if (TYPE(n) != t) {
PyErr_Format(parser_error, "Expected node type %d, got %d.",
t, TYPE(n));
return 0;
}
return 1;
}
/* Verifies that the number of child nodes is exactly 'num', raising
* an exception if it isn't. The exception message does not indicate
* the exact number of nodes, allowing this to be used to raise the
* "right" exception when the wrong number of nodes is present in a
* specific variant of a statement's syntax. This is commonly used
* in that fashion.
*/
static int
validate_numnodes(node *n, int num, const char *const name)
{
if (NCH(n) != num) {
PyErr_Format(parser_error,
"Illegal number of children for %s node.", name);
return 0;
}
return 1;
}
static int
validate_terminal(node *terminal, int type, char *string)
{
int res = (validate_ntype(terminal, type)
&& ((string == 0) || (strcmp(string, STR(terminal)) == 0)));
if (!res && !PyErr_Occurred()) {
PyErr_Format(parser_error,
"Illegal terminal: expected \"%s\"", string);
}
return (res);
}
/* X (',' X) [',']
*/
static int
validate_repeating_list(node *tree, int ntype, int (*vfunc)(node *),
const char *const name)
{
int nch = NCH(tree);
int res = (nch && validate_ntype(tree, ntype)
&& vfunc(CHILD(tree, 0)));
if (!res && !PyErr_Occurred())
(void) validate_numnodes(tree, 1, name);
else {
if (is_even(nch))
res = validate_comma(CHILD(tree, --nch));
if (res && nch > 1) {
int pos = 1;
for ( ; res && pos < nch; pos += 2)
res = (validate_comma(CHILD(tree, pos))
&& vfunc(CHILD(tree, pos + 1)));
}
}
return (res);
}
/* validate_class()
*
* classdef:
* 'class' NAME ['(' testlist ')'] ':' suite
*/
static int
validate_class(node *tree)
{
int nch = NCH(tree);
int res = validate_ntype(tree, classdef) && ((nch == 4) || (nch == 7));
if (res) {
res = (validate_name(CHILD(tree, 0), "class")
&& validate_ntype(CHILD(tree, 1), NAME)
&& validate_colon(CHILD(tree, nch - 2))
&& validate_suite(CHILD(tree, nch - 1)));
}
else
(void) validate_numnodes(tree, 4, "class");
if (res && (nch == 7)) {
res = (validate_lparen(CHILD(tree, 2))
&& validate_testlist(CHILD(tree, 3))
&& validate_rparen(CHILD(tree, 4)));
}
return (res);
}
/* if_stmt:
* 'if' test ':' suite ('elif' test ':' suite)* ['else' ':' suite]
*/
static int
validate_if(node *tree)
{
int nch = NCH(tree);
int res = (validate_ntype(tree, if_stmt)
&& (nch >= 4)
&& validate_name(CHILD(tree, 0), "if")
&& validate_test(CHILD(tree, 1))
&& validate_colon(CHILD(tree, 2))
&& validate_suite(CHILD(tree, 3)));
if (res && ((nch % 4) == 3)) {
/* ... 'else' ':' suite */
res = (validate_name(CHILD(tree, nch - 3), "else")
&& validate_colon(CHILD(tree, nch - 2))
&& validate_suite(CHILD(tree, nch - 1)));
nch -= 3;
}
else if (!res && !PyErr_Occurred())
(void) validate_numnodes(tree, 4, "if");
if ((nch % 4) != 0)
/* Will catch the case for nch < 4 */
res = validate_numnodes(tree, 0, "if");
else if (res && (nch > 4)) {
/* ... ('elif' test ':' suite)+ ... */
int j = 4;
while ((j < nch) && res) {
res = (validate_name(CHILD(tree, j), "elif")
&& validate_colon(CHILD(tree, j + 2))