- ebnf.py: Unused customized error messages now case a warning

DHParser/ebnf.py

@@ -601,7 +601,7 @@ class EBNFCompiler(Compiler):
             if entry not in symbols and not entry.startswith(":"):
                 messages.append(Error(('Symbol "%s" is not defined in grammar %s but appears in '
                                        'the transformation table!') % (entry, self.grammar_name),
-                                      0, Error.UNDEFINED_SYMBOL_IN_TRANSFORMATION_TABLE))
+                                      0, Error.UNDEFINED_SYMBOL_IN_TRANSTABLE_WARNING))
         return messages
 
     def verify_compiler(self, compiler):
@@ -719,6 +719,14 @@ class EBNFCompiler(Compiler):
                 custom_errors.append((search, message))
             definitions.append((symbol + self.ERR_MSG_SUFFIX, repr(custom_errors)))
 
+        for symbol in self.directives.error.keys():
+            if symbol not in self.consumed_custom_errors:
+                def_node = self.rules[symbol][0]
+                self.tree.new_error(
+                    def_node, 'Customized error message for symbol "{}" will never be used, '
+                    'because the mandatory marker "§" appears nowhere in its definiendum!'
+                    .format(symbol), Error.UNUSED_ERROR_MSG_WARNING)
+
         # prepare parser class header and docstring and
         # add EBNF grammar to the doc string of the parser class
 
@@ -1011,8 +1019,6 @@ class EBNFCompiler(Compiler):
                         custom_args.append('err_msgs=' + current_symbol + self.ERR_MSG_SUFFIX)
                         self.consumed_custom_errors.add(current_symbol)
             compiled = self.non_terminal(node, 'Series', custom_args)
-            # TODO: Maybe add a warning about ambiguous error messages in case there are several
-            #       Series with mandatory items within the definiens of the same symbol?
         node.result = saved_result
         return compiled
 

DHParser/error.py

@@ -73,8 +73,9 @@ class Error:
 
     REDEFINED_DIRECTIVE_WARNING              = ErrorCode(110)
     REDECLARED_TOKEN_WARNING                 = ErrorCode(120)
+    UNUSED_ERROR_MSG_WARNING                 = ErrorCode(130)
 
-    UNDEFINED_SYMBOL_IN_TRANSFORMATION_TABLE = ErrorCode(610)
+    UNDEFINED_SYMBOL_IN_TRANSTABLE_WARNING   = ErrorCode(610)
 
     # error codes
 
@@ -86,7 +87,6 @@ class Error:
     CAPTURE_STACK_NOT_EMPTY                  = ErrorCode(1050)
     MALFORMED_ERROR_STRING                   = ErrorCode(1060)
     AMBIGUOUS_ERROR_MSG                      = ErrorCode(1070)
-    UNUSED_ERROR_MSG                         = ErrorCode(1080)
 
     def __init__(self, message: str, pos, code: ErrorCode = ERROR,
                  orig_pos: int = -1, line: int = -1, column: int = -1) -> None:
@@ -138,6 +138,18 @@ def is_error(code: int) -> bool:
     return code >= Error.ERROR
 
 
+# def Warning(message: str, pos, code: ErrorCode = Error.WARNING,
+#             orig_pos: int = -1, line: int = -1, column: int = -1) -> Error:
+#     """
+#     Syntactic sugar for creating Error-objects that contain only a warning.
+#     Raises a ValueError if `code` is not within the range for warnings.
+#     """
+#     if not is_warning(code):
+#         raise ValueError("Tried to create a warning with a error code {}. "
+#                          "Warning codes must be smaller than {}".format(code, Error.ERROR))
+#     return Error(message, pos, code, orig_pos, line, column)
+
+
 def has_errors(messages: Iterable[Error], level: int = Error.ERROR) -> bool:
     """
     Returns True, if at least one entry in `messages` has at

test/test_ebnf.py

@@ -504,14 +504,10 @@ class TestErrorCustomization:
             series = "A" § "B" "C"
             other = "X" | "Y" | "Z"
             """
-        parser = grammar_provider(lang)()  # TODO: Here an error should occur!
-        st = parser("ABC")
-        assert not st.error_flag
-        st = parser("Y")
-        assert not st.error_flag
-        st = parser("ADC")
-        assert st.error_flag
-        print(st.collect_errors())
+        result, messages, ast = compile_source(lang, None, get_ebnf_grammar(),
+                                               get_ebnf_transformer(), get_ebnf_compiler())
+        assert messages[0].code == Error.UNUSED_ERROR_MSG_WARNING
+
 
 class TestCustomizedResumeParsing:
     def setup(self):