TestSemanticPredicateEvaluation.java
/*
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* Copyright (c) 2010 Terence Parr
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package org.antlr.test;
import org.junit.Test;
import static org.junit.Assert.*;
public class TestSemanticPredicateEvaluation extends BaseTest {
@Test public void testSimpleCyclicDFAWithPredicate() throws Exception {
String grammar =
"grammar foo;\n" +
"a : {false}? 'x'* 'y' {System.out.println(\"alt1\");}\n" +
" | {true}? 'x'* 'y' {System.out.println(\"alt2\");}\n" +
" ;\n" ;
String found = execParser("foo.g", grammar, "fooParser", "fooLexer",
"a", "xxxy", false);
assertEquals("alt2\n", found);
}
@Test public void testSimpleCyclicDFAWithInstanceVarPredicate() throws Exception {
String grammar =
"grammar foo;\n" +
"@members {boolean v=true;}\n" +
"a : {false}? 'x'* 'y' {System.out.println(\"alt1\");}\n" +
" | {v}? 'x'* 'y' {System.out.println(\"alt2\");}\n" +
" ;\n" ;
String found = execParser("foo.g", grammar, "fooParser", "fooLexer",
"a", "xxxy", false);
assertEquals("alt2\n", found);
}
@Test public void testPredicateValidation() throws Exception {
String grammar =
"grammar foo;\n" +
"@members {\n" +
"public void reportError(RecognitionException e) {\n" +
" System.out.println(\"error: \"+e.toString());\n" +
"}\n" +
"}\n" +
"\n" +
"a : {false}? 'x'\n" +
" ;\n" ;
String found = execParser("foo.g", grammar, "fooParser", "fooLexer",
"a", "x", false);
assertEquals("error: FailedPredicateException(a,{false}?)\n", found);
}
@Test public void testLexerPreds() throws Exception {
String grammar =
"grammar foo;" +
"@lexer::members {boolean p=false;}\n" +
"a : (A|B)+ ;\n" +
"A : {p}? 'a' {System.out.println(\"token 1\");} ;\n" +
"B : {!p}? 'a' {System.out.println(\"token 2\");} ;\n";
String found = execParser("foo.g", grammar, "fooParser", "fooLexer",
"a", "a", false);
// "a" is ambig; can match both A, B. Pred says match 2
assertEquals("token 2\n", found);
}
@Test public void testLexerPreds2() throws Exception {
String grammar =
"grammar foo;" +
"@lexer::members {boolean p=true;}\n" +
"a : (A|B)+ ;\n" +
"A : {p}? 'a' {System.out.println(\"token 1\");} ;\n" +
"B : ('a'|'b')+ {System.out.println(\"token 2\");} ;\n";
String found = execParser("foo.g", grammar, "fooParser", "fooLexer",
"a", "a", false);
// "a" is ambig; can match both A, B. Pred says match 1
assertEquals("token 1\n", found);
}
@Test public void testLexerPredInExitBranch() throws Exception {
// p says it's ok to exit; it has precendence over the !p loopback branch
String grammar =
"grammar foo;" +
"@lexer::members {boolean p=true;}\n" +
"a : (A|B)+ ;\n" +
"A : ('a' {System.out.print(\"1\");})*\n" +
" {p}?\n" +
" ('a' {System.out.print(\"2\");})* ;\n";
String found = execParser("foo.g", grammar, "fooParser", "fooLexer",
"a", "aaa", false);
assertEquals("222\n", found);
}
@Test public void testLexerPredInExitBranch2() throws Exception {
String grammar =
"grammar foo;" +
"@lexer::members {boolean p=true;}\n" +
"a : (A|B)+ ;\n" +
"A : ({p}? 'a' {System.out.print(\"1\");})*\n" +
" ('a' {System.out.print(\"2\");})* ;\n";
String found = execParser("foo.g", grammar, "fooParser", "fooLexer",
"a", "aaa", false);
assertEquals("111\n", found);
}
@Test public void testLexerPredInExitBranch3() throws Exception {
String grammar =
"grammar foo;" +
"@lexer::members {boolean p=true;}\n" +
"a : (A|B)+ ;\n" +
"A : ({p}? 'a' {System.out.print(\"1\");} | )\n" +
" ('a' {System.out.print(\"2\");})* ;\n";
String found = execParser("foo.g", grammar, "fooParser", "fooLexer",
"a", "aaa", false);
assertEquals("122\n", found);
}
@Test public void testLexerPredInExitBranch4() throws Exception {
String grammar =
"grammar foo;" +
"a : (A|B)+ ;\n" +
"A @init {int n=0;} : ({n<2}? 'a' {System.out.print(n++);})+\n" +
" ('a' {System.out.print(\"x\");})* ;\n";
String found = execParser("foo.g", grammar, "fooParser", "fooLexer",
"a", "aaaaa", false);
assertEquals("01xxx\n", found);
}
@Test public void testLexerPredsInCyclicDFA() throws Exception {
String grammar =
"grammar foo;" +
"@lexer::members {boolean p=false;}\n" +
"a : (A|B)+ ;\n" +
"A : {p}? ('a')+ 'x' {System.out.println(\"token 1\");} ;\n" +
"B : ('a')+ 'x' {System.out.println(\"token 2\");} ;\n";
String found = execParser("foo.g", grammar, "fooParser", "fooLexer",
"a", "aax", false);
assertEquals("token 2\n", found);
}
@Test public void testLexerPredsInCyclicDFA2() throws Exception {
String grammar =
"grammar foo;" +
"@lexer::members {boolean p=false;}\n" +
"a : (A|B)+ ;\n" +
"A : {p}? ('a')+ 'x' ('y')? {System.out.println(\"token 1\");} ;\n" +
"B : ('a')+ 'x' {System.out.println(\"token 2\");} ;\n";
String found = execParser("foo.g", grammar, "fooParser", "fooLexer",
"a", "aax", false);
assertEquals("token 2\n", found);
}
@Test public void testGatedPred() throws Exception {
String grammar =
"grammar foo;" +
"a : (A|B)+ ;\n" +
"A : {true}?=> 'a' {System.out.println(\"token 1\");} ;\n" +
"B : {false}?=>('a'|'b')+ {System.out.println(\"token 2\");} ;\n";
String found = execParser("foo.g", grammar, "fooParser", "fooLexer",
"a", "aa", false);
// "a" is ambig; can match both A, B. Pred says match A twice
assertEquals("token 1\ntoken 1\n", found);
}
@Test public void testGatedPred2() throws Exception {
String grammar =
"grammar foo;\n" +
"@lexer::members {boolean sig=false;}\n"+
"a : (A|B)+ ;\n" +
"A : 'a' {System.out.print(\"A\"); sig=true;} ;\n" +
"B : 'b' ;\n" +
"C : {sig}?=> ('a'|'b') {System.out.print(\"C\");} ;\n";
String found = execParser("foo.g", grammar, "fooParser", "fooLexer",
"a", "aa", false);
assertEquals("AC\n", found);
}
@Test public void testPredWithActionTranslation() throws Exception {
String grammar =
"grammar foo;\n" +
"a : b[2] ;\n" +
"b[int i]\n" +
" : {$i==1}? 'a' {System.out.println(\"alt 1\");}\n" +
" | {$b.i==2}? 'a' {System.out.println(\"alt 2\");}\n" +
" ;\n";
String found = execParser("foo.g", grammar, "fooParser", "fooLexer",
"a", "aa", false);
assertEquals("alt 2\n", found);
}
@Test public void testPredicatesOnEOTTarget() throws Exception {
String grammar =
"grammar foo; \n" +
"@lexer::members {boolean p=true, q=false;}" +
"a : B ;\n" +
"A: '</'; \n" +
"B: {p}? '<!' {System.out.println(\"B\");};\n" +
"C: {q}? '<' {System.out.println(\"C\");}; \n" +
"D: '<';\n" ;
String found = execParser("foo.g", grammar, "fooParser", "fooLexer",
"a", "<!", false);
assertEquals("B\n", found);
}
// S U P P O R T
private void _test() throws Exception {
String grammar =
"grammar T;\n" +
"options {output=AST;}\n" +
"a : ;\n" +
"ID : 'a'..'z'+ ;\n" +
"INT : '0'..'9'+;\n" +
"WS : (' '|'\\n') {channel=99;} ;\n";
String found = execParser("t.g", grammar, "T", "TLexer",
"a", "abc 34", false);
assertEquals("\n", found);
}
}