Support class scoped variable lookup in interpolation lambdas (take 2) (python#45)

Co-authored-by: Lysandros Nikolaou <lisandrosnik@gmail.com>

Author: davepeck

Include/internal/pycore_ast.h

@@ -30,6 +30,7 @@ struct _Py_global_strings {
     struct {
         STRUCT_FOR_STR(anon_dictcomp, "<dictcomp>")
         STRUCT_FOR_STR(anon_genexpr, "<genexpr>")
+        STRUCT_FOR_STR(anon_interpolation, "<interpolation>")
         STRUCT_FOR_STR(anon_lambda, "<lambda>")
         STRUCT_FOR_STR(anon_listcomp, "<listcomp>")
         STRUCT_FOR_STR(anon_module, "<module>")
@@ -493,6 +494,7 @@ struct _Py_global_strings {
         STRUCT_FOR_ID(insert_pis)
         STRUCT_FOR_ID(instructions)
         STRUCT_FOR_ID(intern)
+        STRUCT_FOR_ID(interpolation)
         STRUCT_FOR_ID(intersection)
         STRUCT_FOR_ID(interval)
         STRUCT_FOR_ID(is_running)

Include/internal/pycore_ast_state.h

@@ -70,7 +70,7 @@ DecodedConcrete_repr(PyObject *s)
 {
     PyObject *left = NULL, *repr = NULL, *right = NULL, *leftrepr = NULL;
     PyObject *final = NULL;
-    
+
     left = PyUnicode_FromString("DecodedConcrete(");
     if (left == NULL) {
         goto exit;

Include/internal/pycore_global_objects_fini_generated.h

@@ -80,7 +80,7 @@ module Python
          | FormattedValue(expr value, int conversion, expr? format_spec)
          | JoinedStr(expr* values)
          | TagString(expr tag, expr str)
-         | Interpolation(expr lambda, expr str, expr? conversion, expr? format_spec)
+         | Interpolation(expr body, expr str, expr? conversion, expr? format_spec)
          | Decoded(constant value, string? kind)
          | Constant(constant value, string? kind)
 

Include/internal/pycore_global_strings.h

@@ -1412,17 +1412,6 @@ _PyPegen_name_from_f_string_start(Parser *p, Token* t)
                        t->end_col_offset, p->arena);
 }
 
-static expr_ty
-lambdafy(Parser *p, expr_ty arg)
-{
-    arguments_ty args = _PyPegen_empty_arguments(p);
-    if (args == NULL)
-        return NULL;
-    return _PyAST_Lambda(args, arg,
-            arg->lineno, arg->col_offset, arg->end_lineno, arg->end_col_offset,
-            p->arena);
-}
-
 expr_ty
 _PyPegen_tag_str(Parser *p, Token* a, asdl_expr_seq* raw_expressions, Token*b) {
     expr_ty tag = _PyPegen_name_from_f_string_start(p, a);
@@ -1441,10 +1430,6 @@ _PyPegen_tag_str(Parser *p, Token* a, asdl_expr_seq* raw_expressions, Token*b) {
             if (value->kind == FormattedValue_kind) {
 
                 expr_ty expr = value->v.FormattedValue.value;
-                expr_ty lambda = lambdafy(p, expr);
-                if (lambda == NULL) {
-                    return NULL;
-                }
 
                 constant rawstr = _PyAST_ExprAsUnicode(expr);
                 if (rawstr == NULL) {
@@ -1475,7 +1460,7 @@ _PyPegen_tag_str(Parser *p, Token* a, asdl_expr_seq* raw_expressions, Token*b) {
                 }
 
                 expr_ty spec = value->v.FormattedValue.format_spec;
-                expr_ty interpolation = _PyAST_Interpolation(lambda,
+                expr_ty interpolation = _PyAST_Interpolation(expr,
                         raw, conv, spec,
                         value->lineno, value->col_offset,
                         value->end_lineno, value->end_col_offset,
@@ -1604,7 +1589,6 @@ expr_ty _PyPegen_formatted_value(Parser *p, expr_ty expression, Token *debug, in
             debug_metadata = closing_brace->metadata;
         }
 
-        
         expr_ty debug_text;
         if (debug_as_decoded_ast) {
             debug_text = _PyAST_Decoded(debug_metadata, NULL, lineno, col_offset + 1, debug_end_line,