1/*
2 [The "BSD license"]
3 Copyright (c) 2010 Terence Parr
4 All rights reserved.
5
6 Redistribution and use in source and binary forms, with or without
7 modification, are permitted provided that the following conditions
8 are met:
9 1. Redistributions of source code must retain the above copyright
10    notice, this list of conditions and the following disclaimer.
11 2. Redistributions in binary form must reproduce the above copyright
12    notice, this list of conditions and the following disclaimer in the
13    documentation and/or other materials provided with the distribution.
14 3. The name of the author may not be used to endorse or promote products
15    derived from this software without specific prior written permission.
16
17 THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
18 IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
19 OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
20 IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
21 INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
22 NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
23 DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
24 THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
25 (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
26 THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
27*/
28
29/** We need to set Rule.referencedPredefinedRuleAttributes before
30 *  code generation.  This filter looks at an action in context of
31 *  its rule and outer alternative number and figures out which
32 *  rules have predefined prefs referenced.  I need this so I can
33 *  remove unusued labels.  This also tracks, for labeled rules,
34 *  which are referenced by actions.
35 */
36lexer grammar ActionAnalysis;
37options {
38  filter=true;  // try all non-fragment rules in order specified
39}
40
41@header {
42package org.antlr.grammar.v3;
43import org.antlr.runtime.*;
44import org.antlr.tool.*;
45}
46
47@members {
48Rule enclosingRule;
49Grammar grammar;
50Token actionToken;
51int outerAltNum = 0;
52
53	public ActionAnalysis(Grammar grammar, String ruleName, GrammarAST actionAST)
54	{
55		this(new ANTLRStringStream(actionAST.token.getText()));
56		this.grammar = grammar;
57	    this.enclosingRule = grammar.getLocallyDefinedRule(ruleName);
58	    this.actionToken = actionAST.token;
59	    this.outerAltNum = actionAST.outerAltNum;
60	}
61
62public void analyze() {
63	// System.out.println("###\naction="+actionToken);
64	Token t;
65	do {
66		t = nextToken();
67	} while ( t.getType()!= Token.EOF );
68}
69}
70
71/**	$x.y	x is enclosing rule or rule ref or rule label
72 *			y is a return value, parameter, or predefined property.
73 */
74X_Y :	'$' x=ID '.' y=ID {enclosingRule!=null}?
75		{
76		AttributeScope scope = null;
77		String refdRuleName = null;
78		if ( $x.text.equals(enclosingRule.name) ) {
79			// ref to enclosing rule.
80			refdRuleName = $x.text;
81			scope = enclosingRule.getLocalAttributeScope($y.text);
82		}
83		else if ( enclosingRule.getRuleLabel($x.text)!=null ) {
84			// ref to rule label
85			Grammar.LabelElementPair pair = enclosingRule.getRuleLabel($x.text);
86			pair.actionReferencesLabel = true;
87			refdRuleName = pair.referencedRuleName;
88			Rule refdRule = grammar.getRule(refdRuleName);
89			if ( refdRule!=null ) {
90				scope = refdRule.getLocalAttributeScope($y.text);
91			}
92		}
93		else if ( enclosingRule.getRuleRefsInAlt(x.getText(), outerAltNum)!=null ) {
94			// ref to rule referenced in this alt
95			refdRuleName = $x.text;
96			Rule refdRule = grammar.getRule(refdRuleName);
97			if ( refdRule!=null ) {
98				scope = refdRule.getLocalAttributeScope($y.text);
99			}
100		}
101		if ( scope!=null &&
102			 (scope.isPredefinedRuleScope||scope.isPredefinedLexerRuleScope) )
103		{
104			grammar.referenceRuleLabelPredefinedAttribute(refdRuleName);
105			//System.out.println("referenceRuleLabelPredefinedAttribute for "+refdRuleName);
106		}
107		}
108	;
109
110/** $x	x is an isolated rule label.  Just record that the label was referenced */
111X	:	'$' x=ID {enclosingRule!=null && enclosingRule.getRuleLabel($x.text)!=null}?
112		{
113			Grammar.LabelElementPair pair = enclosingRule.getRuleLabel($x.text);
114			pair.actionReferencesLabel = true;
115		}
116	;
117
118/** $y	y is a return value, parameter, or predefined property of current rule */
119Y	:	'$' ID {enclosingRule!=null && enclosingRule.getLocalAttributeScope($ID.text)!=null}?
120		{
121			AttributeScope scope = enclosingRule.getLocalAttributeScope($ID.text);
122			if ( scope!=null &&
123				 (scope.isPredefinedRuleScope||scope.isPredefinedLexerRuleScope) )
124			{
125				grammar.referenceRuleLabelPredefinedAttribute(enclosingRule.name);
126				//System.out.println("referenceRuleLabelPredefinedAttribute for "+$ID.text);
127			}
128		}
129	;
130
131fragment
132ID  :   ('a'..'z'|'A'..'Z'|'_') ('a'..'z'|'A'..'Z'|'_'|'0'..'9')*
133    ;
134