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clean up of findGuardForGroup in HoistingProcessor

Browse source 
removed special case for non-trivial cardinality - use regular
findGuardForElement instead

adjusted test cases to follow antlr semantic - ignore following
predicates

made HoistingProcessor Singleton

preparation for better caching
This commit is contained in:
overflowerror 2022-01-28 19:57:30 +01:00
parent 00ff0407b0
commit dc950e4bef
2 changed files with 33 additions and 98 deletions
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5
org.eclipse.xtext.tests/src/org/eclipse/xtext/xtext/generator/hoisting/HoistingProcessorTest.java
View file

@ -288,7 +288,7 @@ public class HoistingProcessorTest extends AbstractXtextTests {
HoistingGuard guard = hoistingProcessor.findHoistingGuard(rule.getAlternatives());
assertFalse(guard.isTrivial());
assertTrue(guard.hasTerminal());
assertEquals("((" + getSyntaxForKeywordToken("s", 1) + " || (p1)) && (" + getSyntaxForKeywordToken("a", 1) + " || (p0)))", guard.render());
assertEquals("(" + getSyntaxForKeywordToken("a", 1) + " || (p0))", guard.render());
}
@Test
@ -344,7 +344,7 @@ public class HoistingProcessorTest extends AbstractXtextTests {
HoistingGuard guard = hoistingProcessor.findHoistingGuard(rule.getAlternatives());
assertFalse(guard.isTrivial());
assertTrue(guard.hasTerminal());
assertEquals("((" + getSyntaxForKeywordToken("s", 1) + " || (p1)) && (" + getSyntaxForKeywordToken("a", 1) + " || (p0)))", guard.render());
assertEquals("(" + getSyntaxForKeywordToken("a", 1) + " || (p0))", guard.render());
}
@Test
@ -443,6 +443,7 @@ public class HoistingProcessorTest extends AbstractXtextTests {
// @formatter:off
String model =
MODEL_PREAMBLE +
"hoistingDebug\n" +
"S: ($$ p0 $$?=> 'a')? & ($$ p1 $$?=> 'b');";
// @formatter:off
XtextResource resource = getResourceFromString(model);

110
org.eclipse.xtext.xtext.generator/src/org/eclipse/xtext/xtext/generator/parser/antlr/hoisting/HoistingProcessor.java
View file

@ -63,12 +63,14 @@ import org.eclipse.xtext.xtext.generator.parser.antlr.hoisting.token.Token;
import static org.eclipse.xtext.xtext.generator.parser.antlr.hoisting.utils.DebugUtils.*;
import org.eclipse.xtext.xtext.generator.parser.antlr.hoisting.utils.StreamUtils;
import com.google.inject.Singleton;
/**
* @author overflow - Initial contribution and API
*/
@Singleton
public class HoistingProcessor {
private Map<String, HoistingGuard> ruleCache = new HashMap<>();
private Map<Group, HoistingGuard> groupCache = new HashMap<>();
private Map<String, HoistingGuard> elementCache = new HashMap<>();
private Logger log = Logger.getLogger(this.getClass());
@ -115,7 +117,7 @@ public class HoistingProcessor {
)
);
} catch(TokenAnalysisAbortedException e) {
throw new TokenAnalysisAbortedException(e.getMessage(), e, currentRule);
throw new TokenAnalysisAbortedException(e, currentRule);
}
}
@ -343,18 +345,10 @@ public class HoistingProcessor {
}
private HoistingGuard findGuardForGroup(Group group, AbstractRule currentRule) {
log.info("find guard for group");
GroupGuard groupGuard = new GroupGuard();
Iterator<AbstractElement> iterator = group.getElements().iterator();
while (iterator.hasNext()) {
AbstractElement element = iterator.next();
String cardinality = element.getCardinality();
if (isTrivialCardinality(element) || isOneOrMoreCardinality(element)) {
HoistingGuard guard = findGuardForElementWithTrivialCardinality(element, currentRule);
for(AbstractElement element : group.getElements()) {
HoistingGuard guard = findGuardForElement(element, currentRule);
groupGuard.add(guard);
// if cardinality is + and there is a terminal we don't need to consider
@ -365,66 +359,6 @@ public class HoistingProcessor {
groupGuard.setHasTerminal();
break;
}
} else if (isOptionalCardinality(element)) {
// though not technically necessary, rewrite tree to context checks are not needed
// rewrite cardinality to alternatives
// A? B -> A B | B
// A* B -> A+ B | B -> A B | B (see above)
// make copy of every element because we can't use any element twice
List<AbstractElement> remainingElementsInGroup = StreamUtils.fromIterator(iterator)
.collect(Collectors.toList());
if (remainingElementsInGroup.isEmpty()) {
// B is empty
// context will be taken from parent element
HoistingGuard guard = findGuardForOptionalCardinalityWithoutContext(element, currentRule);
groupGuard.add(guard);
if (guard.hasTerminal()) {
groupGuard.setHasTerminal();
}
// there are no following elements
break;
} else {
// B is non-empty
// -> construct context for alternatives
// we need a clone of the element because we need to set the cardinality without changing the
// original syntax tree
AbstractElement clonedElement = copy(element);
clonedElement.setCardinality(null);
// make copy of first branch and add the cloned element
List<AbstractElement> remainingElementsInGroupIncludingCurrent = new LinkedList<>(remainingElementsInGroup);
remainingElementsInGroupIncludingCurrent.add(0, clonedElement);
Group virtualPathRemaining = XtextFactory.eINSTANCE.createGroup();
setElementsOfCompoundElement(virtualPathRemaining, remainingElementsInGroup);
Group virtualPathRemainingPlusCurrent = XtextFactory.eINSTANCE.createGroup();
setElementsOfCompoundElement(virtualPathRemainingPlusCurrent, remainingElementsInGroupIncludingCurrent);
Alternatives virtualAlternatives = XtextFactory.eINSTANCE.createAlternatives();
setElementsOfCompoundElement(virtualAlternatives, Arrays.asList(virtualPathRemaining, virtualPathRemainingPlusCurrent));
// get Guard for virtual alternatives
HoistingGuard guard = findGuardForElementWithTrivialCardinality(virtualAlternatives, currentRule);
groupGuard.add(guard);
if (guard.hasTerminal()) {
groupGuard.setHasTerminal();
}
// following elements are included in alternative, no need to check further
break;
}
} else {
throw new IllegalArgumentException("unknown cardinality: " + cardinality);
}
}
return groupGuard;
@ -433,13 +367,7 @@ public class HoistingProcessor {
// TODO: make private
public HoistingGuard findGuardForRule(AbstractRule rule) {
log.info("finding guard for rule: " + rule.getName());
HoistingGuard guard = ruleCache.get(rule.getName());
if (guard == null) {
log.info("not in cache");
guard = findGuardForElement(rule.getAlternatives(), rule);
ruleCache.put(rule.getName(), guard);
}
return guard;
return findGuardForElement(rule.getAlternatives(), rule);
}
private boolean pathHasTokenOrAction(AbstractElement path) {
@ -520,15 +448,26 @@ public class HoistingProcessor {
}
private HoistingGuard findGuardForElement(AbstractElement element, AbstractRule currentRule) {
String path = getPathOfElement(element);
HoistingGuard guard = null;//elementCache.get(path);
if (guard != null) {
log.info("from cache: " + path);
return guard;
}
if (isTrivialCardinality(element) ||
isOneOrMoreCardinality(element)
) {
return findGuardForElementWithTrivialCardinality(element, currentRule);
guard = findGuardForElementWithTrivialCardinality(element, currentRule);
} else if (isOptionalCardinality(element)) {
return findGuardForOptionalCardinalityWithoutContext(element, currentRule);
guard = findGuardForOptionalCardinalityWithoutContext(element, currentRule);
} else {
throw new IllegalArgumentException("unknown cardinality: " + element.getCardinality());
}
elementCache.put(path, guard);
return guard;
}
private HoistingGuard findGuardForElementWithTrivialCardinality(AbstractElement element, AbstractRule currentRule) {
@ -538,12 +477,7 @@ public class HoistingProcessor {
if (element instanceof Alternatives) {
return findGuardForAlternatives((Alternatives) element, currentRule);
} else if (element instanceof Group) {
HoistingGuard guard = groupCache.get(element);
if (guard == null) {
guard = findGuardForGroup((Group) element, currentRule);
groupCache.put((Group) element, guard);
}
return guard;
return findGuardForGroup((Group) element, currentRule);
} else if (element instanceof AbstractSemanticPredicate) {
return new PredicateGuard((AbstractSemanticPredicate) element);
} else if (Token.isToken(element)) {