Add ast.Constant
Issue #26146: Add a new kind of AST node: ast.Constant. It can be used by
external AST optimizers, but the compiler does not emit directly such node.
An optimizer can replace the following AST nodes with ast.Constant:
* ast.NameConstant: None, False, True
* ast.Num: int, float, complex
* ast.Str: str
* ast.Bytes: bytes
* ast.Tuple if items are constants too: tuple
* frozenset
Update code to accept ast.Constant instead of ast.Num and/or ast.Str:
* compiler
* docstrings
* ast.literal_eval()
* Tools/parser/unparse.py
diff --git a/Parser/Python.asdl b/Parser/Python.asdl
index 22775c6..aaddf61 100644
--- a/Parser/Python.asdl
+++ b/Parser/Python.asdl
@@ -1,4 +1,8 @@
--- ASDL's six builtin types are identifier, int, string, bytes, object, singleton
+-- ASDL's 7 builtin types are:
+-- identifier, int, string, bytes, object, singleton, constant
+--
+-- singleton: None, True or False
+-- constant can be None, whereas None means "no value" for object.
module Python
{
@@ -76,6 +80,7 @@
| Bytes(bytes s)
| NameConstant(singleton value)
| Ellipsis
+ | Constant(constant value)
-- the following expression can appear in assignment context
| Attribute(expr value, identifier attr, expr_context ctx)
diff --git a/Parser/asdl.py b/Parser/asdl.py
index 121cdab..62f5c19 100644
--- a/Parser/asdl.py
+++ b/Parser/asdl.py
@@ -33,7 +33,8 @@
# See the EBNF at the top of the file to understand the logical connection
# between the various node types.
-builtin_types = {'identifier', 'string', 'bytes', 'int', 'object', 'singleton'}
+builtin_types = {'identifier', 'string', 'bytes', 'int', 'object', 'singleton',
+ 'constant'}
class AST:
def __repr__(self):
diff --git a/Parser/asdl_c.py b/Parser/asdl_c.py
index eedd89b..a81644d 100644
--- a/Parser/asdl_c.py
+++ b/Parser/asdl_c.py
@@ -834,6 +834,7 @@
return (PyObject*)o;
}
#define ast2obj_singleton ast2obj_object
+#define ast2obj_constant ast2obj_object
#define ast2obj_identifier ast2obj_object
#define ast2obj_string ast2obj_object
#define ast2obj_bytes ast2obj_object
@@ -871,6 +872,26 @@
return 0;
}
+static int obj2ast_constant(PyObject* obj, PyObject** out, PyArena* arena)
+{
+ if (obj == Py_None || obj == Py_True || obj == Py_False) {
+ /* don't increment the reference counter, Constant uses a borrowed
+ * reference, not a strong reference */
+ *out = obj;
+ return 0;
+ }
+
+ if (obj) {
+ if (PyArena_AddPyObject(arena, obj) < 0) {
+ *out = NULL;
+ return -1;
+ }
+ Py_INCREF(obj);
+ }
+ *out = obj;
+ return 0;
+}
+
static int obj2ast_identifier(PyObject* obj, PyObject** out, PyArena* arena)
{
if (!PyUnicode_CheckExact(obj) && obj != Py_None) {