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 package org.antlr.test;
29 
30 import org.junit.Test;
31 
32 public class TestSemanticPredicateEvaluation extends BaseTest {
testSimpleCyclicDFAWithPredicate()33 	@Test public void testSimpleCyclicDFAWithPredicate() throws Exception {
34 		String grammar =
35 			"grammar foo;\n" +
36 			"a : {false}? 'x'* 'y' {System.out.println(\"alt1\");}\n" +
37 			"  | {true}?  'x'* 'y' {System.out.println(\"alt2\");}\n" +
38 			"  ;\n" ;
39 		String found = execParser("foo.g", grammar, "fooParser", "fooLexer",
40 				    "a", "xxxy", false);
41 		assertEquals("alt2\n", found);
42 	}
43 
testSimpleCyclicDFAWithInstanceVarPredicate()44 	@Test public void testSimpleCyclicDFAWithInstanceVarPredicate() throws Exception {
45 		String grammar =
46 			"grammar foo;\n" +
47 			"@members {boolean v=true;}\n" +
48 			"a : {false}? 'x'* 'y' {System.out.println(\"alt1\");}\n" +
49 			"  | {v}?     'x'* 'y' {System.out.println(\"alt2\");}\n" +
50 			"  ;\n" ;
51 		String found = execParser("foo.g", grammar, "fooParser", "fooLexer",
52 				    "a", "xxxy", false);
53 		assertEquals("alt2\n", found);
54 	}
55 
testPredicateValidation()56 	@Test public void testPredicateValidation() throws Exception {
57 		String grammar =
58 			"grammar foo;\n" +
59 			"@members {\n" +
60 			"public void reportError(RecognitionException e) {\n" +
61 			"    System.out.println(\"error: \"+e.toString());\n" +
62 			"}\n" +
63 			"}\n" +
64 			"\n" +
65 			"a : {false}? 'x'\n" +
66 			"  ;\n" ;
67 		String found = execParser("foo.g", grammar, "fooParser", "fooLexer",
68 				    "a", "x", false);
69 		assertEquals("error: FailedPredicateException(a,{false}?)\n", found);
70 	}
71 
testLexerPreds()72 	@Test public void testLexerPreds() throws Exception {
73 		String grammar =
74 			"grammar foo;" +
75 			"@lexer::members {boolean p=false;}\n" +
76 			"a : (A|B)+ ;\n" +
77 			"A : {p}? 'a'  {System.out.println(\"token 1\");} ;\n" +
78 			"B : {!p}? 'a' {System.out.println(\"token 2\");} ;\n";
79 		String found = execParser("foo.g", grammar, "fooParser", "fooLexer",
80 				    "a", "a", false);
81 		// "a" is ambig; can match both A, B.  Pred says match 2
82 		assertEquals("token 2\n", found);
83 	}
84 
testLexerPreds2()85 	@Test public void testLexerPreds2() throws Exception {
86 		String grammar =
87 			"grammar foo;" +
88 			"@lexer::members {boolean p=true;}\n" +
89 			"a : (A|B)+ ;\n" +
90 			"A : {p}? 'a' {System.out.println(\"token 1\");} ;\n" +
91 			"B : ('a'|'b')+ {System.out.println(\"token 2\");} ;\n";
92 		String found = execParser("foo.g", grammar, "fooParser", "fooLexer",
93 				    "a", "a", false);
94 		// "a" is ambig; can match both A, B.  Pred says match 1
95 		assertEquals("token 1\n", found);
96 	}
97 
testLexerPredInExitBranch()98 	@Test public void testLexerPredInExitBranch() throws Exception {
99 		// p says it's ok to exit; it has precendence over the !p loopback branch
100 		String grammar =
101 			"grammar foo;" +
102 			"@lexer::members {boolean p=true;}\n" +
103 			"a : (A|B)+ ;\n" +
104 			"A : ('a' {System.out.print(\"1\");})*\n" +
105 			"    {p}?\n" +
106 			"    ('a' {System.out.print(\"2\");})* ;\n";
107 		String found = execParser("foo.g", grammar, "fooParser", "fooLexer",
108 				    "a", "aaa", false);
109 		assertEquals("222\n", found);
110 	}
111 
testLexerPredInExitBranch2()112 	@Test public void testLexerPredInExitBranch2() throws Exception {
113 		String grammar =
114 			"grammar foo;" +
115 			"@lexer::members {boolean p=true;}\n" +
116 			"a : (A|B)+ ;\n" +
117 			"A : ({p}? 'a' {System.out.print(\"1\");})*\n" +
118 			"    ('a' {System.out.print(\"2\");})* ;\n";
119 		String found = execParser("foo.g", grammar, "fooParser", "fooLexer",
120 				    "a", "aaa", false);
121 		assertEquals("111\n", found);
122 	}
123 
testLexerPredInExitBranch3()124 	@Test public void testLexerPredInExitBranch3() throws Exception {
125 		String grammar =
126 			"grammar foo;" +
127 			"@lexer::members {boolean p=true;}\n" +
128 			"a : (A|B)+ ;\n" +
129 			"A : ({p}? 'a' {System.out.print(\"1\");} | )\n" +
130 			"    ('a' {System.out.print(\"2\");})* ;\n";
131 		String found = execParser("foo.g", grammar, "fooParser", "fooLexer",
132 				    "a", "aaa", false);
133 		assertEquals("122\n", found);
134 	}
135 
testLexerPredInExitBranch4()136 	@Test public void testLexerPredInExitBranch4() throws Exception {
137 		String grammar =
138 			"grammar foo;" +
139 			"a : (A|B)+ ;\n" +
140 			"A @init {int n=0;} : ({n<2}? 'a' {System.out.print(n++);})+\n" +
141 			"    ('a' {System.out.print(\"x\");})* ;\n";
142 		String found = execParser("foo.g", grammar, "fooParser", "fooLexer",
143 				    "a", "aaaaa", false);
144 		assertEquals("01xxx\n", found);
145 	}
146 
testLexerPredsInCyclicDFA()147 	@Test public void testLexerPredsInCyclicDFA() throws Exception {
148 		String grammar =
149 			"grammar foo;" +
150 			"@lexer::members {boolean p=false;}\n" +
151 			"a : (A|B)+ ;\n" +
152 			"A : {p}? ('a')+ 'x'  {System.out.println(\"token 1\");} ;\n" +
153 			"B :      ('a')+ 'x' {System.out.println(\"token 2\");} ;\n";
154 		String found = execParser("foo.g", grammar, "fooParser", "fooLexer",
155 				    "a", "aax", false);
156 		assertEquals("token 2\n", found);
157 	}
158 
testLexerPredsInCyclicDFA2()159 	@Test public void testLexerPredsInCyclicDFA2() throws Exception {
160 		String grammar =
161 			"grammar foo;" +
162 			"@lexer::members {boolean p=false;}\n" +
163 			"a : (A|B)+ ;\n" +
164 			"A : {p}? ('a')+ 'x' ('y')? {System.out.println(\"token 1\");} ;\n" +
165 			"B :      ('a')+ 'x' {System.out.println(\"token 2\");} ;\n";
166 		String found = execParser("foo.g", grammar, "fooParser", "fooLexer",
167 				    "a", "aax", false);
168 		assertEquals("token 2\n", found);
169 	}
170 
testGatedPred()171 	@Test public void testGatedPred() throws Exception {
172 		String grammar =
173 			"grammar foo;" +
174 			"a : (A|B)+ ;\n" +
175 			"A : {true}?=> 'a' {System.out.println(\"token 1\");} ;\n" +
176 			"B : {false}?=>('a'|'b')+ {System.out.println(\"token 2\");} ;\n";
177 		String found = execParser("foo.g", grammar, "fooParser", "fooLexer",
178 				    "a", "aa", false);
179 		// "a" is ambig; can match both A, B.  Pred says match A twice
180 		assertEquals("token 1\ntoken 1\n", found);
181 	}
182 
testGatedPred2()183 	@Test public void testGatedPred2() throws Exception {
184 		String grammar =
185 			"grammar foo;\n" +
186 			"@lexer::members {boolean sig=false;}\n"+
187 			"a : (A|B)+ ;\n" +
188 			"A : 'a' {System.out.print(\"A\"); sig=true;} ;\n" +
189 			"B : 'b' ;\n" +
190 			"C : {sig}?=> ('a'|'b') {System.out.print(\"C\");} ;\n";
191 		String found = execParser("foo.g", grammar, "fooParser", "fooLexer",
192 				    "a", "aa", false);
193 		assertEquals("AC\n", found);
194 	}
195 
testPredWithActionTranslation()196 	@Test public void testPredWithActionTranslation() throws Exception {
197 		String grammar =
198 			"grammar foo;\n" +
199 			"a : b[2] ;\n" +
200 			"b[int i]\n" +
201 			"  : {$i==1}?   'a' {System.out.println(\"alt 1\");}\n" +
202 			"  | {$b.i==2}? 'a' {System.out.println(\"alt 2\");}\n" +
203 			"  ;\n";
204 		String found = execParser("foo.g", grammar, "fooParser", "fooLexer",
205 				    "a", "aa", false);
206 		assertEquals("alt 2\n", found);
207 	}
208 
testPredicatesOnEOTTarget()209 	@Test public void testPredicatesOnEOTTarget() throws Exception {
210 		String grammar =
211 			"grammar foo; \n" +
212 			"@lexer::members {boolean p=true, q=false;}" +
213 			"a : B ;\n" +
214 			"A: '</'; \n" +
215 			"B: {p}? '<!' {System.out.println(\"B\");};\n" +
216 			"C: {q}? '<' {System.out.println(\"C\");}; \n" +
217 			"D: '<';\n" ;
218 		String found = execParser("foo.g", grammar, "fooParser", "fooLexer",
219 				    "a", "<!", false);
220 		assertEquals("B\n", found);
221 	}
222 
223 
224 	// S U P P O R T
225 
_test()226 	public void _test() throws Exception {
227 		String grammar =
228 			"grammar T;\n" +
229 			"options {output=AST;}\n" +
230 			"a :  ;\n" +
231 			"ID : 'a'..'z'+ ;\n" +
232 			"INT : '0'..'9'+;\n" +
233 			"WS : (' '|'\\n') {channel=99;} ;\n";
234 		String found = execParser("t.g", grammar, "T", "TLexer",
235 				    "a", "abc 34", false);
236 		assertEquals("\n", found);
237 	}
238 
239 }
240