- error.py: removed unneccessary level attribute

- ebnf.py: attempt to redefine directives will issue a warning

DHParser/ebnf.py

@@ -375,6 +375,7 @@ class EBNFCompiler(Compiler):
     WHITESPACE = {'horizontal': r'[\t ]*',  # default: horizontal
                   'linefeed': r'[ \t]*\n?(?!\s*\n)[ \t]*',
                   'vertical': r'\s*'}
+    REPEATABLE_DIRECTIVES = {'tokens'}
 
 
     def __init__(self, grammar_name="", grammar_source=""):
@@ -393,13 +394,14 @@ class EBNFCompiler(Compiler):
         self.recursive = set()      # type: Set[str]
         self.definitions = {}       # type: Dict[str, str]
         self.deferred_tasks = []    # type: List[Callable]
-        self.root_symbol = ""  # type: str
+        self.root_symbol = ""       # type: str
         self.directives = {'whitespace': self.WHITESPACE['horizontal'],
                            'comment': '',
-                           'literalws': ['right'],
+                           'literalws': {'right'},
                            'tokens': set(),  # alt. 'preprocessor_tokens'
-                           'filter': dict(),  # alt. 'filter'
-                           'ignorecase': False}
+                           'filter': dict()}  # alt. 'filter'
+        # self.directives['ignorecase']: False
+        self.defined_directives = set()  # type: Set[str]
 
     @property
     def result(self) -> str:
@@ -548,7 +550,7 @@ class EBNFCompiler(Compiler):
         defined_symbols.difference_update(self.RESERVED_SYMBOLS)
 
         def remove_connections(symbol):
-            """Recursiviely removes all symbols which appear in the
+            """Recursively removes all symbols which appear in the
             definiens of a particular symbol."""
             if symbol in defined_symbols:
                 defined_symbols.remove(symbol)
@@ -576,12 +578,6 @@ class EBNFCompiler(Compiler):
     def on_syntax(self, node: Node) -> str:
         definitions = []  # type: List[Tuple[str, str]]
 
-        # transfer directives to re_flags where needed
-        if self.directives['ignorecase']:
-            self.re_flags.add('i')
-        elif 'i' in self.re_flags:
-            self.re_flags.remove('i')
-
         # drop the wrapping sequence node
         if len(node.children) == 1 and not node.children[0].parser.name:
             node = node.children[0]
@@ -658,6 +654,14 @@ class EBNFCompiler(Compiler):
         key = str(node.children[0]).lower()
         assert key not in self.directives['tokens']
 
+        if key not in self.REPEATABLE_DIRECTIVES:
+            if key in self.defined_directives:
+                node.add_error('Directive "%s" has already been defined earlier. ' % key + \
+                               'Later definition will be ignored!',
+                               code=Error.REDEFINED_DIRECTIVE_WARNING)
+                return ""
+            self.defined_directives.add(key)
+
         if key in {'comment', 'whitespace'}:
             if node.children[1].parser.name == "list_":
                 if len(node.children[1].result) != 1:
@@ -683,12 +687,8 @@ class EBNFCompiler(Compiler):
             self.directives[key] = value
 
         elif key == 'ignorecase':
-            value = str(node.children[1]).lower() not in {"off", "false", "no"}
-            self.directives['ignorecase'] == value
-            if value:
+            if str(node.children[1]).lower() not in {"off", "false", "no"}:
                 self.re_flags.add('i')
-            elif 'i' in self.re_flags:
-                self.re_flags.remove('i')
 
         # elif key == 'testing':
         #     value = str(node.children[1])
@@ -706,7 +706,13 @@ class EBNFCompiler(Compiler):
             self.directives[key] = list(wsp)
 
         elif key in {'tokens', 'preprocessor_tokens'}:
-            self.directives['tokens'] |= self.compile(node.children[1])
+            tokens = self.compile(node.children[1])
+            redeclared = self.directives['tokes'] & tokens
+            if redeclared:
+                node.add_error('Tokens %s have already been declared earlier. '
+                               % str(redeclared) + 'Later declaration will be ignored',
+                               code=Error.REDECLARED_TOKEN_WARNING)
+            self.directives['tokens'] |= tokens - redeclared
 
         elif key.endswith('_filter'):
             filter_set = self.compile(node.children[1])

DHParser/error.py

@@ -42,15 +42,18 @@ class Error:
     ERROR     = 1000
     HIGHEST   = ERROR
 
+    # warning codes
+
+    REDEFINED_DIRECTIVE_WARNING = 101
+
     # error codes
 
     MANDATORY_CONTINUATION = 1001
 
-    def __init__(self, message: str, level: int = ERROR, code: int = 0,
+    def __init__(self, message: str, code: int = ERROR,
                  pos: int = -1, line: int = -1, column: int = -1) -> None:
         self.message = message
-        assert level >= 0
-        self.level = level or Error.ERROR
+        assert code >= 0
         self.code = code
         self.pos = pos
         self.line = line
@@ -70,17 +73,17 @@ class Error:
     def level_str(self):
         """Returns a string representation of the error level, e.g. "warning".
         """
-        return "Warning" if is_warning(self.level) else "Error"
+        return "Warning" if is_warning(self.code) else "Error"
 
 
-def is_warning(level: int) -> bool:
+def is_warning(code: int) -> bool:
     """Returns True, if error is merely a warning."""
-    return level < Error.ERROR
+    return code < Error.ERROR
 
 
-def is_error(level: int) -> bool:
+def is_error(code: int) -> bool:
     """Returns True, if error is an error, not just a warning."""
-    return level >= Error.ERROR
+    return code >= Error.ERROR
 
 
 def has_errors(messages: Iterable[Error], level: int = Error.ERROR) -> bool:
@@ -89,7 +92,7 @@ def has_errors(messages: Iterable[Error], level: int = Error.ERROR) -> bool:
     least the given error `level`.
     """
     for err_obj in messages:
-        if err_obj.level >= level:
+        if err_obj.code >= level:
             return True
     return False
 

DHParser/syntaxtree.py

@@ -370,8 +370,7 @@ class Node(collections.abc.Sized):
 
     def add_error(self,
                   message: str,
-                  level: int = Error.ERROR,
-                  code: int = 0) -> 'Node':
+                  code: int = Error.ERROR) -> 'Node':
         """
         Adds an error to this Node.
         Parameters:
@@ -379,8 +378,8 @@ class Node(collections.abc.Sized):
             level(int):     The error level (error or warning)
             code(Hashable): An error code to identify the kind of error
         """
-        self._errors.append(Error(message, level, code))
-        self.error_flag = max(self.error_flag, self._errors[-1].level)
+        self._errors.append(Error(message, code))
+        self.error_flag = max(self.error_flag, self._errors[-1].code)
         return self