Merge pull request python#61 from isidentical/solve-conversion-handle

Author: pablogsal

Grammar/python.gram

@@ -194,7 +194,7 @@ yield_stmt[stmt_ty]: y=yield_expr { _PyAST_Expr(y, EXTRA) }
 
 assert_stmt[stmt_ty]: 'assert' a=expression b=[',' z=expression { z }] { _PyAST_Assert(a, b, EXTRA) }
 
-import_stmt[stmt_ty]: 
+import_stmt[stmt_ty]:
     | invalid_import
     | import_name
     | import_from
@@ -415,8 +415,8 @@ try_stmt[stmt_ty]:
     | invalid_try_stmt
     | 'try' &&':' b=block f=finally_block { _PyAST_Try(b, NULL, NULL, f, EXTRA) }
     | 'try' &&':' b=block ex[asdl_excepthandler_seq*]=except_block+ el=[else_block] f=[finally_block] { _PyAST_Try(b, ex, el, f, EXTRA) }
-    | 'try' &&':' b=block ex[asdl_excepthandler_seq*]=except_star_block+ el=[else_block] f=[finally_block] { 
-        CHECK_VERSION(stmt_ty, 11, "Exception groups are", 
+    | 'try' &&':' b=block ex[asdl_excepthandler_seq*]=except_star_block+ el=[else_block] f=[finally_block] {
+        CHECK_VERSION(stmt_ty, 11, "Exception groups are",
                       _PyAST_TryStar(b, ex, el, f, EXTRA)) }
 
 
@@ -1263,7 +1263,7 @@ invalid_group:
 invalid_import:
     | a='import' dotted_name 'from' dotted_name {
         RAISE_SYNTAX_ERROR_STARTING_FROM(a, "Did you mean to use 'from ... import ...' instead?") }
- 
+
 invalid_import_from_targets:
     | import_from_as_names ',' NEWLINE {
         RAISE_SYNTAX_ERROR("trailing comma not allowed without surrounding parentheses") }
@@ -1362,3 +1362,7 @@ invalid_replacement_field:
     | '{' a=':' { RAISE_SYNTAX_ERROR_KNOWN_LOCATION(a, "f-string: expression required before ':'") }
     | '{' a='!' { RAISE_SYNTAX_ERROR_KNOWN_LOCATION(a, "f-string: expression required before '!'") }
     | '{' a='}' { RAISE_SYNTAX_ERROR_KNOWN_LOCATION(a, "f-string: empty expression not allowed") }
+    | '{' (yield_expr | star_expressions) "="? invalid_conversion_character
+invalid_conversion_character:
+    | a="!" &(':'|'}') { RAISE_SYNTAX_ERROR_KNOWN_LOCATION(a, "f-string: missed conversion character") }
+    | a="!" !NAME { RAISE_SYNTAX_ERROR_KNOWN_LOCATION(a, "f-string: invalid conversion character") }

Lib/test/test_fstring.py

@@ -1120,11 +1120,16 @@ def test_conversions(self):
                              "f'{3!:}'",
                              ])
 
-        for conv in 'g', 'A', '3', 'G', '!', 'ä', 'ɐ', 'ª':
+        for conv_identifier in 'g', 'A', 'G', 'ä', 'ɐ', 'ª':
             self.assertAllRaise(SyntaxError,
                                 "f-string: invalid conversion character %r: "
-                                "expected 's', 'r', or 'a'" % conv,
-                                ["f'{3!" + conv + "}'"])
+                                "expected 's', 'r', or 'a'" % conv_identifier,
+                                ["f'{3!" + conv_identifier + "}'"])
+
+        for conv_non_identifier in '3', '!':
+            self.assertAllRaise(SyntaxError,
+                                "f-string: invalid conversion character",
+                                ["f'{3!" + conv_non_identifier + "}'"])
 
         for conv in ' s', ' s ':
             self.assertAllRaise(SyntaxError,