From 8fbf4fa9edcb9efd1ca5d650ed235eb4770dea3a Mon Sep 17 00:00:00 2001
From: Benjamin Peterson <benjamin@python.org>
Date: Thu, 6 Dec 2012 17:41:04 -0500
Subject: create NameConstant AST class for None, True, and False literals
 (closes #16619)

---
 Python/ast.c | 22 ++++++++++++++++++----
 1 file changed, 18 insertions(+), 4 deletions(-)

(limited to 'Python/ast.c')

diff --git a/Python/ast.c b/Python/ast.c
index 7657b22459..50603033d5 100644
--- a/Python/ast.c
+++ b/Python/ast.c
@@ -282,6 +282,7 @@ validate_expr(expr_ty exp, expr_context_ty ctx)
         return validate_exprs(exp->v.Tuple.elts, ctx, 0);
     /* These last cases don't have any checking. */
     case Name_kind:
+    case NameConstant_kind:
     case Ellipsis_kind:
         return 1;
     default:
@@ -903,7 +904,7 @@ set_context(struct compiling *c, expr_ty e, expr_context_ty ctx, const node *n)
             break;
         case Name_kind:
             if (ctx == Store) {
-                if (forbidden_name(c, e->v.Name.id, n, 1))
+                if (forbidden_name(c, e->v.Name.id, n, 0))
                     return 0; /* forbidden_name() calls ast_error() */
             }
             e->v.Name.ctx = ctx;
@@ -955,6 +956,9 @@ set_context(struct compiling *c, expr_ty e, expr_context_ty ctx, const node *n)
         case Bytes_kind:
             expr_name = "literal";
             break;
+        case NameConstant_kind:
+            expr_name = "keyword";
+            break;
         case Ellipsis_kind:
             expr_name = "Ellipsis";
             break;
@@ -1819,11 +1823,21 @@ ast_for_atom(struct compiling *c, const node *n)
 
     switch (TYPE(ch)) {
     case NAME: {
-        /* All names start in Load context, but may later be
-           changed. */
-        PyObject *name = NEW_IDENTIFIER(ch);
+        PyObject *name;
+        const char *s = STR(ch);
+        size_t len = strlen(s);
+        if (len >= 4 && len <= 5) {
+            if (!strcmp(s, "None"))
+                return NameConstant(Py_None, LINENO(n), n->n_col_offset, c->c_arena);
+            if (!strcmp(s, "True"))
+                return NameConstant(Py_True, LINENO(n), n->n_col_offset, c->c_arena);
+            if (!strcmp(s, "False"))
+                return NameConstant(Py_False, LINENO(n), n->n_col_offset, c->c_arena);
+        }
+        name = new_identifier(s, c);
         if (!name)
             return NULL;
+        /* All names start in Load context, but may later be changed. */
         return Name(name, Load, LINENO(n), n->n_col_offset, c->c_arena);
     }
     case STRING: {
-- 
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