bpo-42128: Structural Pattern Matching (PEP 634) (GH-22917)
Co-authored-by: Guido van Rossum <guido@python.org>
Co-authored-by: Talin <viridia@gmail.com>
Co-authored-by: Pablo Galindo <pablogsal@gmail.com>
diff --git a/Python/ast.c b/Python/ast.c
index 5e74f65..c58b4a6 100644
--- a/Python/ast.c
+++ b/Python/ast.c
@@ -309,6 +309,14 @@ validate_expr(expr_ty exp, expr_context_ty ctx)
return validate_exprs(exp->v.Tuple.elts, ctx, 0);
case NamedExpr_kind:
return validate_expr(exp->v.NamedExpr.value, Load);
+ case MatchAs_kind:
+ PyErr_SetString(PyExc_ValueError,
+ "MatchAs is only valid in match_case patterns");
+ return 0;
+ case MatchOr_kind:
+ PyErr_SetString(PyExc_ValueError,
+ "MatchOr is only valid in match_case patterns");
+ return 0;
/* This last case doesn't have any checking. */
case Name_kind:
return 1;
@@ -318,6 +326,13 @@ validate_expr(expr_ty exp, expr_context_ty ctx)
}
static int
+validate_pattern(expr_ty p)
+{
+ // Coming soon (thanks Batuhan)!
+ return 1;
+}
+
+static int
_validate_nonempty_seq(asdl_seq *seq, const char *what, const char *owner)
{
if (asdl_seq_LEN(seq))
@@ -415,6 +430,20 @@ validate_stmt(stmt_ty stmt)
return 0;
}
return validate_body(stmt->v.AsyncWith.body, "AsyncWith");
+ case Match_kind:
+ if (!validate_expr(stmt->v.Match.subject, Load)
+ || !validate_nonempty_seq(stmt->v.Match.cases, "cases", "Match")) {
+ return 0;
+ }
+ for (i = 0; i < asdl_seq_LEN(stmt->v.Match.cases); i++) {
+ match_case_ty m = asdl_seq_GET(stmt->v.Match.cases, i);
+ if (!validate_pattern(m->pattern)
+ || (m->guard && !validate_expr(m->guard, Load))
+ || !validate_body(m->body, "match_case")) {
+ return 0;
+ }
+ }
+ return 1;
case Raise_kind:
if (stmt->v.Raise.exc) {
return validate_expr(stmt->v.Raise.exc, Load) &&