BDFL says, we deliver!

Author: sobolevn

Grammar/python.gram

@@ -129,6 +129,7 @@ simple_stmt[stmt_ty] (memo):
 compound_stmt[stmt_ty]:
     | &('def' | '@' | 'async') function_def
     | &'if' if_stmt
+    | &"maybe" maybe_stmt
     | &('class' | '@') class_def
     | &('with' | 'async') with_stmt
     | &('for' | 'async') for_stmt
@@ -366,6 +367,11 @@ default[expr_ty]: '=' a=expression { a } | invalid_default
 # If statement
 # ------------
 
+maybe_stmt[stmt_ty]:
+    | invalid_maybe_stmt
+    | "maybe" a=named_expression ':' b=block c=elif_stmt {
+        _PyAST_If(a, b, CHECK(asdl_stmt_seq*, _PyPegen_singleton_seq(p, c)), EXTRA) }
+    | "maybe" a=named_expression ':' b=block c=[else_block] { _PyAST_If(a, b, c, EXTRA) }
 if_stmt[stmt_ty]:
     | invalid_if_stmt
     | 'if' a=named_expression ':' b=block c=elif_stmt {
@@ -1401,6 +1407,10 @@ invalid_class_pattern:
         "positional patterns follow keyword patterns") }
 invalid_class_argument_pattern[asdl_pattern_seq*]:
     | [positional_patterns ','] keyword_patterns ',' a=positional_patterns { a }
+invalid_maybe_stmt:
+    | "maybe" named_expression NEWLINE { RAISE_SYNTAX_ERROR("expected ':'") }
+    | a="maybe" a=named_expression ':' NEWLINE !INDENT {
+        RAISE_INDENTATION_ERROR("expected an indented block after 'if' statement on line %d", a->lineno) }
 invalid_if_stmt:
     | 'if' named_expression NEWLINE { RAISE_SYNTAX_ERROR("expected ':'") }
     | a='if' a=named_expression ':' NEWLINE !INDENT {