Tagged String syntax -- RAISES SYNTAX ERROR

python · gvanrossum · May 1, 2022 · May 2, 2022 · May 2, 2022 · May 2, 2022
commit 1b61a5e3c65ed8d505958f955cba063762dd57b5
@@ -796,6 +796,7 @@ slice[expr_ty]:
     | a=named_expression { a }
 
 atom[expr_ty]:
+    | a=NAME &STRING b=strings  { _PyPegen_tag_string(p, a, b) }
     | NAME
     | 'True' { _PyAST_Constant(Py_True, NULL, EXTRA) }
     | 'False' { _PyAST_Constant(Py_False, NULL, EXTRA) }

diff --git a/Include/internal/pycore_ast.h b/Include/internal/pycore_ast.h
@@ -77,6 +77,7 @@ module Python
          | Call(expr func, expr* args, keyword* keywords)
          | FormattedValue(expr value, int conversion, expr? format_spec)
          | JoinedStr(expr* values)
+         | TagString(expr tag, expr str)
          | Constant(constant value, string? kind)
 
          -- the following expression can appear in assignment context

@@ -869,6 +869,19 @@ _PyPegen_seq_delete_starred_exprs(Parser *p, asdl_seq *kwargs)
     return new_seq;
 }
 
+expr_ty
+_PyPegen_tag_string(Parser *p, expr_ty tag, expr_ty str)
+{
+    // No prefixes (f, r, b, u)
+    // Parse like fstring
+    // Create a node similar to f-string AST
+    return _PyAST_TagString(tag, str,
+                            tag->lineno, tag->col_offset, str->end_lineno, str->end_col_offset,
+                            p->arena);
+
+}
+
+
 expr_ty
 _PyPegen_concatenate_strings(Parser *p, asdl_seq *strings)
 {

@@ -317,6 +317,7 @@ expr_ty _PyPegen_collect_call_seqs(Parser *, asdl_expr_seq *, asdl_seq *,
                      int lineno, int col_offset, int end_lineno,
                      int end_col_offset, PyArena *arena);
 expr_ty _PyPegen_concatenate_strings(Parser *p, asdl_seq *);
+expr_ty _PyPegen_tag_string(Parser *p, expr_ty, expr_ty);
 expr_ty _PyPegen_ensure_imaginary(Parser *p, expr_ty);
 expr_ty _PyPegen_ensure_real(Parser *p, expr_ty);
 asdl_seq *_PyPegen_join_sequences(Parser *, asdl_seq *, asdl_seq *);

diff --git a/Python/Python-ast.c b/Python/Python-ast.c
@@ -321,6 +321,10 @@ validate_expr(struct validator *state, expr_ty exp, expr_context_ty ctx)
     case JoinedStr_kind:
         ret = validate_exprs(state, exp->v.JoinedStr.values, Load, 0);
         break;
+    case TagString_kind:
+        ret = validate_expr(state, exp->v.TagString.tag, Load) &&
+            validate_expr(state, exp->v.TagString.str, Load);
+        break;
     case FormattedValue_kind:
         if (validate_expr(state, exp->v.FormattedValue.value, Load) == 0)
             return 0;

@@ -4691,6 +4691,7 @@ check_caller(struct compiler *c, expr_ty e)
     case SetComp_kind:
     case GeneratorExp_kind:
     case JoinedStr_kind:
+    case TagString_kind:
     case FormattedValue_kind:
         return compiler_warn(c, "'%.200s' object is not callable; "
                                 "perhaps you missed a comma?",
@@ -4750,6 +4751,7 @@ check_index(struct compiler *c, expr_ty e, expr_ty s)
     case List_kind:
     case ListComp_kind:
     case JoinedStr_kind:
+    case TagString_kind:
     case FormattedValue_kind:
         return compiler_warn(c, "%.200s indices must be integers or slices, "
                                 "not %.200s; "
@@ -5835,6 +5837,9 @@ compiler_visit_expr1(struct compiler *c, expr_ty e)
         break;
     case JoinedStr_kind:
         return compiler_joined_str(c, e);
+    case TagString_kind:
+        return compiler_error(c, "TagString not yet supported");
+        break;
     case FormattedValue_kind:
         return compiler_formatted_value(c, e);
     /* The following exprs can be assignment targets. */