- UnknownParserError added to parser.py

DHParser/parse.py

@@ -72,6 +72,7 @@ from typing import Any, Callable, cast, Dict, List, Set, Tuple, Union, Optional
 
 __all__ = ('HistoryRecord',
            'Parser',
+           'UnknownParserError',
            'Grammar',
            'PreprocessorToken',
            'RegExp',
@@ -526,6 +527,12 @@ def mixin_comment(whitespace: str, comment: str) -> str:
     return wspc
 
 
+class UnknownParserError(KeyError):
+    """UnknownParserError is raised if a Grammer object is called with a
+    parser that does not exist or if in the course of parsing a parser
+    is reffered to that does not exist."""
+
+
 class Grammar:
     r"""
     Class Grammar directs the parsing process and stores global state
@@ -801,7 +808,7 @@ class Grammar:
                 parser.apply(self._add_parser__)
                 # assert self[key] == parser
                 return self[key]
-            raise KeyError('Unknown parser "%s" !' % key)
+            raise UnknownParserError('Unknown parser "%s" !' % key)
 
 
     def _reset__(self):
@@ -1004,8 +1011,8 @@ class Grammar:
 
         if not is_logging():
             raise AssertionError("Cannot log history when logging is turned off!")
-        assert self.history__, \
-            "Parser did not yet run or logging was turned off when running parser!"
+        # assert self.history__, \
+        #     "Parser did not yet run or logging was turned off when running parser!"
         if not log_file_name:
             name = self.__class__.__name__
             log_file_name = name[:-7] if name.lower().endswith('grammar') else name

DHParser/syntaxtree.py

@@ -35,6 +35,7 @@ __all__ = ('ParserBase',
            'ZOMBIE_PARSER',
            'Node',
            'mock_syntax_tree',
+           'flatten_sxpr',
            'TransformationFunc')
 
 

DHParser/testing.py

@@ -24,7 +24,8 @@ import json
 import os
 
 from DHParser.toolkit import is_logging, clear_logs, re
-from DHParser.syntaxtree import mock_syntax_tree, flatten_sxpr
+from DHParser.syntaxtree import Node, mock_syntax_tree, flatten_sxpr, ZOMBIE_PARSER
+from DHParser.parse import UnknownParserError
 from DHParser.error import is_error, adjust_error_locations
 
 __all__ = ('unit_from_configfile',
@@ -172,7 +173,10 @@ def grammar_unit(test_unit, parser_factory, transformer_factory, report=True, ve
             if verbose:
                 infostr = '    match-test "' + test_name + '" ... '
                 errflag = len(errata)
-            cst = parser(test_code, parser_name)
+            try:
+                cst = parser(test_code, parser_name)
+            except UnknownParserError as upe:
+                cst = Node(ZOMBIE_PARSER, "").add_error(str(upe)).init_pos(0)
             cst.log("match_%s_%s.cst" % (parser_name, test_name))
             tests.setdefault('__cst__', {})[test_name] = cst
             if "ast" in tests or report:
@@ -210,7 +214,11 @@ def grammar_unit(test_unit, parser_factory, transformer_factory, report=True, ve
             if verbose:
                 infostr = '    fail-test  "' + test_name + '" ... '
                 errflag = len(errata)
-            cst = parser(test_code, parser_name)
+            # cst = parser(test_code, parser_name)
+            try:
+                cst = parser(test_code, parser_name)
+            except UnknownParserError as upe:
+                cst = Node(ZOMBIE_PARSER, "").add_error(str(upe)).init_pos(0)
             if not is_error(cst.error_flag):
                 errata.append('Fail test "%s" for parser "%s" yields match instead of '
                               'expected failure!' % (test_name, parser_name))

test/test_parse.py

@@ -29,7 +29,8 @@ from DHParser.stringview import StringView
 from DHParser.error import Error
 from DHParser.syntaxtree import mock_syntax_tree
 from DHParser.parse import compile_source, Retrieve, Grammar, Forward, Token, ZeroOrMore, RE, \
-    RegExp, Lookbehind, NegativeLookahead, OneOrMore, Series, Alternative, AllOf, SomeOf, Compiler
+    RegExp, Lookbehind, NegativeLookahead, OneOrMore, Series, Alternative, AllOf, SomeOf, Compiler, \
+    UnknownParserError
 from DHParser.ebnf import get_ebnf_grammar, get_ebnf_transformer, get_ebnf_compiler
 from DHParser.dsl import grammar_provider, DHPARSER_IMPORTS
 
@@ -562,6 +563,16 @@ class TestCompilerClass:
         assert D.error_flag
 
 
+class TestUnknownParserError:
+    def test_unknown_parser_error(self):
+        gr = Grammar()
+        try:
+            gr("", "NonExistantParser")
+            assert False, "UnknownParserError expected!"
+        except UnknownParserError:
+            pass
+
+
 if __name__ == "__main__":
     from DHParser.testing import runner
     with logging(False):