ebnf.EBNFCompiler and parsers.Grammar now raise errors when parsing rules can...

ebnf.EBNFCompiler and parsers.Grammar now raise errors when parsing rules can never be reached from the root parser

DHParser/dsl.py

@@ -127,7 +127,6 @@ class CompilationError(Exception):
     """Raised when a string or file in a domain specific language (DSL)
     contains errors.
     """
-
     def __init__(self, error_messages, dsl_text, dsl_grammar, AST, result):
         self.error_messages = error_messages
         self.dsl_text = dsl_text

DHParser/parsers.py

@@ -345,7 +345,14 @@ class Grammar:
         self.root__.apply(self._add_parser)
 
     def __getitem__(self, key):
-        return getattr(self, key)
+        try:
+            return self.__dict__[key]
+        except KeyError:
+            parser = getattr(self, key, None)
+            if parser:
+                raise KeyError(('Parser "%s" inaccesible, because it is not connected '
+                                'to the root parser "%s" !') % (key,  self.root__.name))
+            raise KeyError('Unknown parser "%s" !' % key)
 
     def _reset(self):
         # variables stored and recalled by Capture and Retrieve parsers

DHParser/testing.py

@@ -87,7 +87,7 @@ def mock_syntax_tree(sexpr):
     return Node(MockParser(name, ':' + class_name), result)
 
 
-def recompile_grammar(ebnf_filename):
+def recompile_grammar(ebnf_filename, force=False):
     """Recompiles an ebnf-grammar if necessary, that is if either no
     corresponding 'XXXXCompiler.py'-file exists or if that file is
     outdated.
@@ -97,17 +97,19 @@ def recompile_grammar(ebnf_filename):
             grammar. In case this is a directory and not a file all
             files within this directory ending with .ebnf will be 
             compiled.
+        force(bool):  If False (default), the grammar will only be
+            recompiled if it has been changed.
     """
     if os.path.isdir(ebnf_filename):
         for entry in os.listdir(ebnf_filename):
             if entry.lower().endswith('.ebnf') and os.path.isfile(entry):
-                recompile_grammar(entry)
+                recompile_grammar(entry, force)
         return
 
     base, ext = os.path.splitext(ebnf_filename)
     compiler_name = base + 'Compiler.py'
     errors = []
-    if (not os.path.exists(compiler_name) or
+    if (not os.path.exists(compiler_name) or force or
         grammar_changed(compiler_name, ebnf_filename)):
         # print("recompiling parser for: " + ebnf_filename)
         errors = compile_on_disk(ebnf_filename)

examples/LaTeX/recompile_grammar.py

@@ -25,4 +25,4 @@ import sys
 sys.path.extend(['../../', '../', './'])
 
 from DHParser.testing import recompile_grammar
-recompile_grammar('.')
+recompile_grammar('.', True)

test/test_ebnf.py

@@ -25,10 +25,10 @@ from multiprocessing import Pool
 import sys
 sys.path.extend(['../', './'])
 
-from DHParser.toolkit import is_logging
+from DHParser.toolkit import is_logging, compile_python_object
 from DHParser.parsers import compile_source, Retrieve, WHITESPACE_PTYPE, nil_scanner
 from DHParser.ebnf import get_ebnf_grammar, get_ebnf_transformer, EBNFTransformer, get_ebnf_compiler
-from DHParser.dsl import CompilationError, compileDSL, parser_factory
+from DHParser.dsl import CompilationError, compileDSL, DHPARSER_IMPORTS, parser_factory
 
 
 class TestDirectives:
@@ -281,8 +281,6 @@ class TestSelfHosting:
         repetition =  "{" expression §"}"
         option     =  "[" expression §"]"
 
-        link       = regexp | symbol | literal           # semantic restriction: symbol must evaluate to a regexp or chain
-
         symbol     =  /(?!\d)\w+/~                       # e.g. expression, factor, parameter_list
         literal    =  /"(?:[^"]|\\")*?"/~                # e.g. "(", '+', 'while'
                     | /'(?:[^']|\\')*?'/~                # whitespace following literals will be ignored tacitly.
@@ -353,9 +351,22 @@ class TestBoundaryCases:
             grammar = parser_factory(ebnf)()
             assert False, "EBNF compiler should complain about unconnected rules."
         except CompilationError as err:
-            grammar = err.result
-        assert grammar.__dict__['root']
-        assert grammar.__dict__['unconnected']
+            grammar_src = err.result
+            grammar = compile_python_object(DHPARSER_IMPORTS + grammar_src,
+                                            'get_(?:\w+_)?grammar$')()
+        assert grammar['root'], "Grammar objects should be subscriptable by parser names!"
+        try:
+            unconnected = grammar['unconnected']
+            assert False, "Grammar objects should raise a KeyError if subscripted by " \
+                          "names of parsers that are unconnected to the root parser!"
+        except KeyError:
+            pass
+        try:
+            nonexistant = grammar['nonexistant']
+            assert False, "Grammar object shoul raise a KeyError if subscripted by " \
+                          "a non-existant parser name!"
+        except KeyError:
+            pass
 
 
 class TestSynonymDetection: