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bpo-43892: Make match patterns explicit in the AST (GH-25585)

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Co-authored-by: Brandt Bucher <brandtbucher@gmail.com>
This commit is contained in:
Nick Coghlan 2021-04-29 15:58:44 +10:00 • committed by GitHub
parent e52ab42ced
commit 1e7b858575
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20 changed files with 3460 additions and 1377 deletions
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64
Python/symtable.c
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@ -214,6 +214,7 @@ static int symtable_implicit_arg(struct symtable *st, int pos);
static int symtable_visit_annotations(struct symtable *st, arguments_ty, expr_ty);
static int symtable_visit_withitem(struct symtable *st, withitem_ty item);
static int symtable_visit_match_case(struct symtable *st, match_case_ty m);
static int symtable_visit_pattern(struct symtable *st, pattern_ty s);
static identifier top = NULL, lambda = NULL, genexpr = NULL,
@ -246,7 +247,6 @@ symtable_new(void)
goto fail;
st->st_cur = NULL;
st->st_private = NULL;
st->in_pattern = 0;
return st;
fail:
_PySymtable_Free(st);
@ -1676,13 +1676,6 @@ symtable_visit_expr(struct symtable *st, expr_ty e)
VISIT(st, expr, e->v.Slice.step)
break;
case Name_kind:
// Don't make "_" a local when used in a pattern:
if (st->in_pattern &&
e->v.Name.ctx == Store &&
_PyUnicode_EqualToASCIIString(e->v.Name.id, "_"))
{
break;
}
if (!symtable_add_def(st, e->v.Name.id,
e->v.Name.ctx == Load ? USE : DEF_LOCAL))
VISIT_QUIT(st, 0);
@ -1702,12 +1695,55 @@ symtable_visit_expr(struct symtable *st, expr_ty e)
case Tuple_kind:
VISIT_SEQ(st, expr, e->v.Tuple.elts);
break;
}
VISIT_QUIT(st, 1);
}
static int
symtable_visit_pattern(struct symtable *st, pattern_ty p)
{
if (++st->recursion_depth > st->recursion_limit) {
PyErr_SetString(PyExc_RecursionError,
"maximum recursion depth exceeded during compilation");
VISIT_QUIT(st, 0);
}
switch (p->kind) {
case MatchValue_kind:
VISIT(st, expr, p->v.MatchValue.value);
break;
case MatchSingleton_kind:
/* Nothing to do here. */
break;
case MatchSequence_kind:
VISIT_SEQ(st, pattern, p->v.MatchSequence.patterns);
break;
case MatchStar_kind:
if (p->v.MatchStar.name) {
symtable_add_def(st, p->v.MatchStar.name, DEF_LOCAL);
}
break;
case MatchMapping_kind:
VISIT_SEQ(st, expr, p->v.MatchMapping.keys);
VISIT_SEQ(st, pattern, p->v.MatchMapping.patterns);
if (p->v.MatchMapping.rest) {
symtable_add_def(st, p->v.MatchMapping.rest, DEF_LOCAL);
}
break;
case MatchClass_kind:
VISIT(st, expr, p->v.MatchClass.cls);
VISIT_SEQ(st, pattern, p->v.MatchClass.patterns);
VISIT_SEQ(st, pattern, p->v.MatchClass.kwd_patterns);
break;
case MatchAs_kind:
VISIT(st, expr, e->v.MatchAs.pattern);
symtable_add_def(st, e->v.MatchAs.name, DEF_LOCAL);
if (p->v.MatchAs.pattern) {
VISIT(st, pattern, p->v.MatchAs.pattern);
}
if (p->v.MatchAs.name) {
symtable_add_def(st, p->v.MatchAs.name, DEF_LOCAL);
}
break;
case MatchOr_kind:
VISIT_SEQ(st, expr, e->v.MatchOr.patterns);
VISIT_SEQ(st, pattern, p->v.MatchOr.patterns);
break;
}
VISIT_QUIT(st, 1);
@ -1830,11 +1866,7 @@ symtable_visit_withitem(struct symtable *st, withitem_ty item)
static int
symtable_visit_match_case(struct symtable *st, match_case_ty m)
{
assert(!st->in_pattern);
st->in_pattern = 1;
VISIT(st, expr, m->pattern);
assert(st->in_pattern);
st->in_pattern = 0;
VISIT(st, pattern, m->pattern);
if (m->guard) {
VISIT(st, expr, m->guard);
}