Ignore the EOF rule

EOF is not a real rule in ANTLR, it works as a parsing instruction to
ensure to match the entire file. However, during generation it doesn't
have any importance, hence it can be safely ignored.

examples/fuzzer/HTMLGenerator.py

@@ -1,4 +1,4 @@
-# Generated by Grammarinator 23.7.post72+gccf98cc
+# Generated by Grammarinator 23.7.post71+g23fe545
 
 from math import inf
 from grammarinator.runtime import *
@@ -37,9 +37,6 @@ def _style_sheet(self):
     def _endOfHtmlElement(self):
         pass
 
-    def EOF(self, parent=None):
-        return None
-
     def HTML_COMMENT(self, parent=None):
         with UnlexerRuleContext(self, 'HTML_COMMENT', parent) as rule:
             current = rule.current
@@ -727,10 +724,9 @@ def style(self, parent=None):
 
     _default_rule = htmlDocument
 
-    _immutable_rules = ('EOF', 'TAG_CLOSE', 'TAG_EQUALS', 'TAG_OPEN', 'TAG_SLASH', 'TAG_SLASH_CLOSE')
+    _immutable_rules = ('TAG_CLOSE', 'TAG_EQUALS', 'TAG_OPEN', 'TAG_SLASH', 'TAG_SLASH_CLOSE')
 
     _rule_sizes = {
-        'EOF': RuleSize(0, 0),
         'HTML_COMMENT': RuleSize(0, 0),
         'HTML_CONDITIONAL_COMMENT': RuleSize(0, 0),
         'XML_DECLARATION': RuleSize(0, 0),

grammarinator/tool/parser.py

@@ -14,7 +14,7 @@
 from os.path import basename, commonprefix, split, splitext
 from subprocess import CalledProcessError, PIPE, run
 
-from antlr4 import CommonTokenStream, error, FileStream, ParserRuleContext, TerminalNode, Token
+from antlr4 import CommonTokenStream, error, FileStream, ParserRuleContext, TerminalNode
 
 from ..runtime import RuleSize, UnlexerRule, UnparserRule
 
@@ -168,7 +168,7 @@ def _antlr_to_grammarinator_tree(self, antlr_node, parser, visited=None):
                 depth = max(depth, child_depth + 1)
         else:
             assert isinstance(antlr_node, TerminalNode), f'An ANTLR node must either be a ParserRuleContext or a TerminalNode but {antlr_node.__class__.__name__} was found.'
-            name, text = (parser.symbolicNames[antlr_node.symbol.type], antlr_node.symbol.text) if antlr_node.symbol.type != Token.EOF else ('EOF', '')
+            name, text = (parser.symbolicNames[antlr_node.symbol.type], antlr_node.symbol.text)
             assert name, f'{name} is None or empty'
 
             if not self._hidden:

grammarinator/tool/processor.py

@@ -989,7 +989,7 @@ def build_expr(node, parent_id):
                             if '_dot' not in graph.vertices:
                                 # Create an artificial `_dot` rule with an alternation of all the lexer rules.
                                 parser_dot_id = graph.add_node(UnparserRuleNode(name='_dot', label=None))
-                                unlexer_ids = [v.name for vid, v in graph.vertices.items() if isinstance(v, UnlexerRuleNode) and v.id != 'EOF']
+                                unlexer_ids = [v.name for vid, v in graph.vertices.items() if isinstance(v, UnlexerRuleNode)]
                                 alt_id = graph.add_node(AlternationNode(rule_id=parser_dot_id, idx=0, conditions=[1] * len(unlexer_ids)))
                                 graph.add_edge(frm=parser_dot_id, to=alt_id)
                                 for i, lexer_id in enumerate(unlexer_ids):
@@ -1033,7 +1033,8 @@ def build_expr(node, parent_id):
 
                 elif isinstance(node, ANTLRv4Parser.TerminalContext):
                     if node.TOKEN_REF():
-                        graph.add_edge(frm=parent_id, to=str(node.TOKEN_REF()))
+                        if str(node.TOKEN_REF() != 'EOF'):
+                            graph.add_edge(frm=parent_id, to=str(node.TOKEN_REF()))
 
                     elif node.STRING_LITERAL():
                         src = unescape_string(str(node.STRING_LITERAL())[1:-1])
@@ -1136,7 +1137,6 @@ def build_rules(node):
 
         graph = GrammarGraph()
         lambda_id = graph.add_node(LambdaNode())
-        graph.add_node(UnlexerRuleNode(name='EOF'))
 
         for root in [lexer_root, parser_root]:
             if root:

grammarinator/tool/resources/codegen/GeneratorTemplate.py.jinja

@@ -146,7 +146,6 @@ class {{ graph.name }}({{ graph.superclass }}):
 
     {% for rule in graph.rules %}
     def {{ rule.id }}(self, {% for t, k, v in rule.args %}{{ k }}{% if t %}:{{ t }}{% endif %}{% if v %}={{ resolveVarRefs(v) }}{% endif %}, {% endfor %}parent=None):
-        {% if rule.id != 'EOF' %}
         {% if rule.labels or rule.args or rule.locals or rule.returns %}
         local_ctx = {
             {%- for _, k, _ in rule.args -%}
@@ -169,9 +168,6 @@ class {{ graph.name }}({{ graph.superclass }}):
             current.{{ k }} = local_ctx['{{ k }}']
             {% endfor %}
             return current
-        {% else %}
-        return None
-        {% endif %}
 
     {% endfor %}