bugfixes

DHParser/dsl.py

@@ -82,8 +82,9 @@ from DHParser.parsers import Grammar, Compiler, nil_scanner, \\
     last_value, counterpart, accumulate, ScannerFunc
 from DHParser.syntaxtree import Node, traverse, remove_enclosing_delimiters, \\
     remove_children_if, reduce_single_child, replace_by_single_child, remove_whitespace, \\
-    no_transformation, remove_expendables, remove_tokens, flatten, is_whitespace, is_expendable, \\
-    collapse, map_content, WHITESPACE_PTYPE, TOKEN_PTYPE, TransformationFunc
+    no_transformation, remove_expendables, remove_empty, remove_tokens, flatten, is_whitespace, \\
+    is_empty, is_expendable, collapse, map_content, WHITESPACE_PTYPE, TOKEN_PTYPE, \\
+    TransformationFunc
 '''
 
 
@@ -257,7 +258,6 @@ def parser_factory(ebnf_src: str, branding="DSL") -> Grammar:
     """
     grammar_src = compileDSL(ebnf_src, nil_scanner, get_ebnf_grammar(),
                              get_ebnf_transformer(), get_ebnf_compiler(branding))
-    print(grammar_src)
     return compile_python_object(DHPARSER_IMPORTS + grammar_src, 'get_(?:\w+_)?grammar$')
 
 

DHParser/ebnf.py

@@ -356,9 +356,10 @@ class EBNFCompiler(Compiler):
         transtable = [tt_name + ' = {',
                       '    # AST Transformations for the ' +
                       self.grammar_name + '-grammar']
+        transtable.append('    "+": remove_empty,')
         for name in self.rules:
             transtable.append('    "' + name + '": no_transformation,')
-        transtable += ['    "*": no_transformation', '}', '', tf_name +
+        transtable += ['    "*": replace_by_single_child', '}', '', tf_name +
                        ' = partial(traverse, processing_table=%s)' % tt_name, '']
         transtable += [TRANSFORMER_FACTORY.format(NAME=self.grammar_name)]
         return '\n'.join(transtable)

DHParser/parsers.py

@@ -390,7 +390,9 @@ class Grammar:
         particular instance of Grammar.
         """
         if parser.name:
-            assert parser.name not in self.__dict__, \
+            # prevent overwriting instance variables or parsers of a different class
+            assert parser.name not in self.__dict__ or \
+                   isinstance(self.__dict__[parser.name], parser.__class__), \
                 ('Cannot add parser "%s" because a field with the same name '
                  'already exists in grammar object!' % parser.name)
             setattr(self, parser.name, parser)

DHParser/syntaxtree.py

@@ -58,6 +58,7 @@ __all__ = ['WHITESPACE_PTYPE',
            'is_token',
            'remove_children_if',
            'remove_whitespace',
+           'remove_empty',
            'remove_expendables',
            'remove_tokens',
            'flatten',
@@ -755,8 +756,8 @@ def remove_children_if(node, condition):
 
 
 remove_whitespace = remove_children_if(is_whitespace)  # partial(remove_children_if, condition=is_whitespace)
+remove_empty = remove_children_if(is_empty)
 remove_expendables = remove_children_if(is_expendable)  # partial(remove_children_if, condition=is_expendable)
-# remove_scanner_tokens = remove_children_if(is_scanner_token)  # partial(remove_children_if, condition=is_scanner_token)
 
 
 @transformation_factory
@@ -777,7 +778,8 @@ def remove_enclosing_delimiters(node):
         node.result = node.result[1:-1]
 
 
-def map_content(node, func: Callable[[Node], ResultType]):
+@transformation_factory
+def map_content(node, func: Callable):      # Callable[[Node], ResultType]
     """Replaces the content of the node. ``func`` takes the node
     as an argument an returns the mapped result.
     """

examples/LaTeX/grammar_tests/test_paragraph.ini

@@ -15,4 +15,5 @@
 
     Im allgemeinen werden die Bewohner Göttingens eingeteilt in Studenten,
     Professoren, Philister und Vieh; welche vier Stände doch nichts weniger
-    als streng geschieden sind. Der Viehstand ist der bedeutendste.
\ No newline at end of file
+    als streng geschieden sind. Der Viehstand ist der bedeutendste.
+