From b09f7ed6235783fca27a4f8730c4c33e0f53c16c Mon Sep 17 00:00:00 2001 From: Guido van Rossum Date: Sun, 15 Jul 2001 21:08:29 +0000 Subject: [PATCH] Preliminary support for "from __future__ import generators" to enable 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. --- Include/compile.h | 3 +++ Lib/__future__.py | 1 + Lib/inspect.py | 2 ++ Lib/tokenize.py | 2 ++ Lib/types.py | 1 + Parser/parser.c | 38 +++++++++++++++++++++++++++++++++++--- Parser/parser.h | 1 + Python/future.c | 2 ++ 8 files changed, 47 insertions(+), 3 deletions(-) diff --git a/Include/compile.h b/Include/compile.h index b9a735a5df5..5e6e572ab45 100644 --- a/Include/compile.h +++ b/Include/compile.h @@ -65,6 +65,9 @@ DL_IMPORT(PyCodeObject *) PyNode_CompileFlags(struct _node *, char *, #define NESTED_SCOPES_DEFAULT 1 #define FUTURE_NESTED_SCOPES "nested_scopes" +#define GENERATORS_DEFAULT 0 +#define FUTURE_GENERATORS "generators" + /* for internal use only */ #define _PyCode_GETCODEPTR(co, pp) \ ((*(co)->co_code->ob_type->tp_as_buffer->bf_getreadbuffer) \ diff --git a/Lib/__future__.py b/Lib/__future__.py index 8510cebc4e9..65416ae3910 100644 --- a/Lib/__future__.py +++ b/Lib/__future__.py @@ -67,3 +67,4 @@ class _Feature: `self.getMandatoryRelease()` + ")" nested_scopes = _Feature((2, 1, 0, "beta", 1), (2, 2, 0, "alpha", 0)) +generators = _Feature((2, 2, 0, "alpha", 1), (2, 3, 0, "final", 0)) diff --git a/Lib/inspect.py b/Lib/inspect.py index 2d88bc1f642..6183b0ee5b5 100644 --- a/Lib/inspect.py +++ b/Lib/inspect.py @@ -24,6 +24,8 @@ Here are some of the useful functions provided by this module: # This module is in the public domain. No warranties. +from __future__ import generators + __author__ = 'Ka-Ping Yee ' __date__ = '1 Jan 2001' diff --git a/Lib/tokenize.py b/Lib/tokenize.py index b79cdc00163..cbe45529c28 100644 --- a/Lib/tokenize.py +++ b/Lib/tokenize.py @@ -22,6 +22,8 @@ are the same, except instead of generating tokens, tokeneater is a callback function to which the 5 fields described above are passed as 5 arguments, each time a new token is found.""" +from __future__ import generators + __author__ = 'Ka-Ping Yee ' __credits__ = \ 'GvR, ESR, Tim Peters, Thomas Wouters, Fred Drake, Skip Montanaro' diff --git a/Lib/types.py b/Lib/types.py index 85962bada48..95600a3b9aa 100644 --- a/Lib/types.py +++ b/Lib/types.py @@ -2,6 +2,7 @@ Types that are part of optional modules (e.g. array) are not listed. """ +from __future__ import generators import sys diff --git a/Parser/parser.c b/Parser/parser.c index 6eaa925ef3c..753c43ac9c9 100644 --- a/Parser/parser.c +++ b/Parser/parser.c @@ -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")); diff --git a/Parser/parser.h b/Parser/parser.h index cf8d3186972..b0c9a1eeb34 100644 --- a/Parser/parser.h +++ b/Parser/parser.h @@ -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); diff --git a/Python/future.c b/Python/future.c index cf2dca5ea5a..70be26b5485 100644 --- a/Python/future.c +++ b/Python/future.c @@ -31,6 +31,8 @@ future_check_features(PyFutureFeatures *ff, node *n, char *filename) feature = STR(CHILD(ch, 0)); if (strcmp(feature, FUTURE_NESTED_SCOPES) == 0) { ff->ff_nested_scopes = 1; + } else if (strcmp(feature, FUTURE_GENERATORS) == 0) { + /* OK; this is processed by the parser */ } else if (strcmp(feature, "braces") == 0) { PyErr_SetString(PyExc_SyntaxError, "not a chance");