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Preliminary support for "from __future__ import generators" to enable

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the yield statement.  I figure we have to have this in before I can
release 2.2a1 on Wednesday.

Note: test_generators is currently broken, I'm counting on Tim to fix
this.
This commit is contained in:
Guido van Rossum 2001-07-15 21:08:29 +00:00
parent 045ca7ae72
commit b09f7ed623
8 changed files with 47 additions and 3 deletions
Download patch file Download diff file Expand all files Collapse all files

38
Parser/parser.c
View file

@ -79,6 +79,7 @@ PyParser_New(grammar *g, int start)
if (ps == NULL)
return NULL;
ps->p_grammar = g;
ps->p_generators = 0;
ps->p_tree = PyNode_New(start);
if (ps->p_tree == NULL) {
PyMem_DEL(ps);
@ -131,8 +132,9 @@ push(register stack *s, int type, dfa *d, int newstate, int lineno)
/* PARSER PROPER */
static int
classify(grammar *g, int type, char *str)
classify(parser_state *ps, int type, char *str)
{
grammar *g = ps->p_grammar;
register int n = g->g_ll.ll_nlabels;
if (type == NAME) {
@ -143,6 +145,10 @@ classify(grammar *g, int type, char *str)
if (l->lb_type == NAME && l->lb_str != NULL &&
l->lb_str[0] == s[0] &&
strcmp(l->lb_str, s) == 0) {
if (!ps->p_generators &&
s[0] == 'y' &&
strcmp(s, "yield") == 0)
break; /* not a keyword */
D(printf("It's a keyword\n"));
return n - i;
}
@ -164,6 +170,22 @@ classify(grammar *g, int type, char *str)
return -1;
}
static void
future_hack(parser_state *ps)
{
node *n = ps->p_stack.s_top->s_parent;
node *ch;
if (strcmp(STR(CHILD(n, 0)), "from") != 0)
return;
ch = CHILD(n, 1);
if (strcmp(STR(CHILD(ch, 0)), "__future__") != 0)
return;
ch = CHILD(n, 3);
if (NCH(ch) == 1 && strcmp(STR(CHILD(ch, 0)), "generators") == 0)
ps->p_generators = 1;
}
int
PyParser_AddToken(register parser_state *ps, register int type, char *str,
int lineno, int *expected_ret)
@ -174,7 +196,7 @@ PyParser_AddToken(register parser_state *ps, register int type, char *str,
D(printf("Token %s/'%s' ... ", _PyParser_TokenNames[type], str));
/* Find out which label this token is */
ilabel = classify(ps->p_grammar, type, str);
ilabel = classify(ps, type, str);
if (ilabel < 0)
return E_SYNTAX;
@ -217,7 +239,14 @@ PyParser_AddToken(register parser_state *ps, register int type, char *str,
while (s = &d->d_state
[ps->p_stack.s_top->s_state],
s->s_accept && s->s_narcs == 1) {
D(printf(" Direct pop.\n"));
D(printf(" DFA '%s', state %d: "
"Direct pop.\n",
d->d_name,
ps->p_stack.s_top->s_state));
if (d->d_name[0] == 'i' &&
strcmp(d->d_name,
"import_stmt") == 0)
future_hack(ps);
s_pop(&ps->p_stack);
if (s_empty(&ps->p_stack)) {
D(printf(" ACCEPT.\n"));
@ -230,6 +259,9 @@ PyParser_AddToken(register parser_state *ps, register int type, char *str,
}
if (s->s_accept) {
if (d->d_name[0] == 'i' &&
strcmp(d->d_name, "import_stmt") == 0)
future_hack(ps);
/* Pop this dfa and try again */
s_pop(&ps->p_stack);
D(printf(" Pop ...\n"));

1
Parser/parser.h
View file

@ -25,6 +25,7 @@ typedef struct {
stack p_stack; /* Stack of parser states */
grammar *p_grammar; /* Grammar to use */
node *p_tree; /* Top of parse tree */
int p_generators; /* 1 if yield is a keyword */
} parser_state;
parser_state *PyParser_New(grammar *g, int start);