jasder
/
antlr
1
0
Fork 1
Code Issues Pull Requests Releases 1 Wiki Activity

simplified delete configs algorithm.

This commit is contained in:
Terence Parr 2012-09-29 12:48:20 -07:00
parent 84c786da50
commit b56cd0f587
3 changed files with 24 additions and 31 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

34
runtime/Java/src/org/antlr/v4/runtime/atn/LexerATNSimulator.java
View File

@ -42,8 +42,6 @@ import org.antlr.v4.runtime.misc.Nullable;
import java.io.IOException;
import java.io.OutputStream;
import java.util.HashSet;
import java.util.Set;
/** "dup" of ParserInterpreter */
public class LexerATNSimulator extends ATNSimulator {
@ -433,10 +431,11 @@ public class LexerATNSimulator extends ATNSimulator {
captureSimState(prevAccept, input, c);
}
// if we reach lexer accept state, toss out any configs pointing
// at wildcard edges in rest of configs work list associated
// with this rule (config.alt); that rule is done. this is how
// we cut off nongreedy .+ loops.
// if we reach lexer accept state with empty stack,
// toss out any configs pointing at wildcard edges
// in rest of configs work list associated with this
// rule (config.alt); that rule is done. this is how we
// cut off nongreedy .+ loops.
reach = deleteWildcardConfigsForAlt(reach, ci, c);
// move to next char, looking for longer match
@ -528,13 +527,16 @@ public class LexerATNSimulator extends ATNSimulator {
}
/** Delete configs for alt following ci that have a wildcard edge but
* only for configs with same stack. E.g., if we want to kill after
* only for configs with empty stack. E.g., if we want to kill after
* config (2,1,[$]), then we need to wack only configs with $ stack:
*
* [..., (2,1,[$]), ..., (7,1,[[$, 6 $]])]
*
* That means wacking (7,1,[$]) but not (7,1,[6 $]). If incoming config
* has multiple stacks, must look for each one in other configs.
* That means wacking (7,1,[$]) but not (7,1,[6 $]).
*
* Incoming config could have multiple stacks but we only care about
* empty stack since that means we reached end of a lexer rule from
* nextToken directly.
*
* Closure is unmodified; copy returned.
*/
@ -547,13 +549,6 @@ public class LexerATNSimulator extends ATNSimulator {
System.out.printf("deleteWildcardConfigsForAlt for alt %d after config %d\n", alt, ci);
}
// collect ctxs from incoming config; must wack all of those.
Set<SingletonPredictionContext> contextsToKill =
new HashSet<SingletonPredictionContext>();
for (SingletonPredictionContext ctx : config.context) {
contextsToKill.add(ctx);
}
ATNConfigSet dup = new ATNConfigSet(); // build up as we go thru loop
for (int j=0; j<=ci; j++) dup.add(closure.get(j)); // add stuff up to ci
int j=ci+1;
@ -562,11 +557,10 @@ public class LexerATNSimulator extends ATNSimulator {
boolean isWildcard = c.state.getClass() == ATNState.class && // plain state only, not rulestop etc..
c.state.transition(0) instanceof WildcardTransition;
if ( c.alt == alt && isWildcard ) {
// found config to kill but only if same stack.
// find c stacks that are in contextsToKill
// found config to kill but only if empty stack.
for (SingletonPredictionContext ctx : c.context) {
if ( contextsToKill.contains(ctx) ) {
// c.alt, c.ctx matches and j > ci => kill it
if ( ctx.isEmpty() ) {
// c.alt matches, empty stack, and j > ci => kill it
if ( debug ) {
System.out.format("delete config %s since alt %d and %d leads to wildcard\n",
c, c.alt, c.state.stateNumber);

9
tool/playground/L.g
View File

@ -1,7 +1,6 @@
lexer grammar L;
STRING_START : '"' {pushMode(STRING_MODE); more();} ;
WS : ' '|'
' {skip();} ;
STRING_START : '"' -> pushMode(STRING_MODE), more ;
WS : (' '|'\n') -> skip ;
mode STRING_MODE;
STRING : '"' {popMode();} ;
ANY : . {more();} ;
STRING : '"' -> popMode ;
ANY : . -> more ;

12
tool/test/org/antlr/v4/test/TestLexerExec.java
View File

@ -125,12 +125,12 @@ public class TestLexerExec extends BaseTest {
"STRING_START : '\"' -> pushMode(STRING_MODE), more ;\n" +
"WS : (' '|'\n') -> skip ;\n"+
"mode STRING_MODE;\n"+
"STRING : '\"' -> popMode ;\n"+
"STRING : '\"' -> popMode ;\n"+ // token type 2
"ANY : . -> more ;\n";
String found = execLexer("L.g4", grammar, "L", "\"abc\" \"ab\"");
String expecting =
"[@0,0:4='\"abc\"',<3>,1:0]\n" +
"[@1,6:9='\"ab\"',<3>,1:6]\n" +
"[@0,0:4='\"abc\"',<2>,1:0]\n" +
"[@1,6:9='\"ab\"',<2>,1:6]\n" +
"[@2,10:9='<EOF>',<-1>,1:10]\n";
assertEquals(expecting, found);
}
@ -141,12 +141,12 @@ public class TestLexerExec extends BaseTest {
"STRING_START : '\"' -> mode(STRING_MODE), more ;\n" +
"WS : (' '|'\n') -> skip ;\n"+
"mode STRING_MODE;\n"+
"STRING : '\"' -> mode(DEFAULT_MODE) ;\n"+
"STRING : '\"' -> mode(DEFAULT_MODE) ;\n"+ // ttype 2 since '"' ambiguity
"ANY : . -> more ;\n";
String found = execLexer("L.g4", grammar, "L", "\"abc\" \"ab\"");
String expecting =
"[@0,0:4='\"abc\"',<3>,1:0]\n" +
"[@1,6:9='\"ab\"',<3>,1:6]\n" +
"[@0,0:4='\"abc\"',<2>,1:0]\n" +
"[@1,6:9='\"ab\"',<2>,1:6]\n" +
"[@2,10:9='<EOF>',<-1>,1:10]\n";
assertEquals(expecting, found);
}