Improved exception handling.

Parse no longer prints the errors, unless in debug. Parse now gathers all
the errors and throw them when it's done parsing (returning as many errors
as possible at once, without returning silently).

plyplus/__init__.py

@@ -1,2 +1,2 @@
-from plyplus import Grammar, SVisitor, STransformer, is_stree
+from plyplus import Grammar, SVisitor, STransformer, is_stree, PlyplusException
 

plyplus/plyplus.py

@@ -98,7 +98,13 @@ def get_token_name(token, default):
         ']' : 'RSQB',
     }.get( token, default)
 
-class GrammarException(Exception): pass
+class PlyplusException(Exception): pass
+
+class GrammarException(PlyplusException): pass
+
+class TokenizeError(PlyplusException): pass
+
+class ParseError(PlyplusException): pass
 
 class GetTokenDefs_Visitor(SVisitor):
     def __init__(self, dict_to_populate):
@@ -424,7 +430,7 @@ def __init__(self, grammar, **options):
 
         grammar_tree = grammar_parser.parse(grammar) #, debug=options.get('debug',False))
         if not grammar_tree:
-            raise GrammarException("Parse Error")
+            raise GrammarException("Parse Error: Could not create grammar")
 
         self._grammar = _Grammar(grammar_tree, source, tab_filename, **options)
 
@@ -502,9 +508,12 @@ def lex(self, text):
         return toks
 
     def parse(self, text):
+        self.errors = []
         tree = self.parser.parse(text, lexer=self.lexer, debug=self.debug)
         if not tree:
-            raise Exception("Parse error!")
+            self.errors.append("Could not create parse tree!")
+        if self.errors:
+            raise ParseError('\n'.join(self.errors))
 
         # Apply subgrammars
         if self.subgrammars:
@@ -521,7 +530,7 @@ def _add_option(self, name, defin):
         if name == '%newline_char':
             self._newline_value = eval(defin)   # XXX BAD BAD! I have TODO it differently
         else:
-            print "Unknown option:", name
+            raise GrammarException( "Unknown option: %s " % name )
 
     @staticmethod
     def _unescape_token_def(token_def):
@@ -609,16 +618,21 @@ def _add_rule(self, rule_name, rule_def):
 
     @staticmethod
     def t_error(t):
-        raise Exception("Illegal character in input: '%s', line: %s, %s" % (t.value[:32], t.lineno, t.type))
+        raise TokenizeError("Illegal character in input: '%s', line: %s, %s" % (t.value[:32], t.lineno, t.type))
 
     def p_error(self, p):
         if p:
             if isinstance(p.value, TokValue):
-                print "Syntax error in input at '%s' (type %s)" % (p.value,p.type), 'line',p.value.line, 'col', p.value.column
+                msg = "Syntax error in input at '%s' (type %s) line %s col %s" % (p.value, p.type, p.value.line, p.value.column)
             else:
-                print "Syntax error in input at '%s' (type %s)" % (p.value,p.type), 'line',p.lineno
+                msg = "Syntax error in input at '%s' (type %s) line %s" % (p.value, p.type, p.lineno)
         else:
-            print "Syntax error in input (details unknown)", p
+            msg = "Syntax error in input (details unknown)", p
+
+        if self.debug:
+            print msg
+
+        self.errors.append(msg)
 
     start = "start"