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added basic support (sub optimal) support for unordered groups

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This commit is contained in:
overflowerror 2021-11-27 20:30:31 +01:00
parent 5110d180b7
commit 8d5af71314
2 changed files with 29 additions and 4 deletions
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4
org.eclipse.xtext.tests/src/org/eclipse/xtext/xtext/generator/hoisting/HoistingProcessorTest.java
View file

@ -287,7 +287,9 @@ public class HoistingProcessorTest extends AbstractXtextTests {
HoistingGuard guard = hoistingProcessor.findGuardForElement(rule.getAlternatives());
assertFalse(guard.isTrivial());
assertTrue(guard.hasTerminal());
assertEquals("((" + getSyntaxForKeywordToken("a", 1) + " || (p0)) && (" + getSyntaxForKeywordToken("b", 1) + " || (p1)) && (" + getSyntaxForKeywordToken("c", 1) + " || (p2)))", guard.render());
// non-optimal version
assertEquals("((" + getSyntaxForKeywordToken("s", 1) + " || (p2)) && ((" + getSyntaxForKeywordToken("a", 1) + " && " + getSyntaxForKeywordToken("b", 1) + ") || ((" + getSyntaxForKeywordToken("a", 1)+ " || (p0)) && (" + getSyntaxForKeywordToken("b", 1) + " || (p1)))))", guard.render());
//assertEquals("((" + getSyntaxForKeywordToken("a", 1) + " || (p0)) && (" + getSyntaxForKeywordToken("b", 1) + " || (p1)) && (" + getSyntaxForKeywordToken("c", 1) + " || (p2)))", guard.render());
}
@Test

29
org.eclipse.xtext.xtext.generator/src/org/eclipse/xtext/xtext/generator/parser/antlr/hoisting/HoistingProcessor.java
View file

@ -127,12 +127,33 @@ public class HoistingProcessor {
}
}
private List<AbstractElement> rewriteUnorderedGroupsAndGetElements(Group group) {
List<AbstractElement> elements = new ArrayList<>(group.getElements());
int size = elements.size();
for (int i = 0; i < size; i++) {
AbstractElement element = elements.get(i);
if (element instanceof UnorderedGroup) {
// Unordered group (A & B) is the same as (A | B)*
// -> create virtual element
Alternatives virtualAlternatives = XtextFactory.eINSTANCE.createAlternatives();
addElementsToCompoundElement(virtualAlternatives, ((UnorderedGroup) element).getElements());
virtualAlternatives.setCardinality("*");
elements.set(i, virtualAlternatives);
}
}
return elements;
}
private HoistingGuard findGuardForGroup(Group group) {
log.info("find guard for group");
GroupGuard groupGuard = new GroupGuard();
Iterator<AbstractElement> iterator = new ArrayList<>(group.getElements()).iterator();
Iterator<AbstractElement> iterator = rewriteUnorderedGroupsAndGetElements(group).iterator();
while (iterator.hasNext()) {
AbstractElement element = iterator.next();
@ -157,6 +178,7 @@ public class HoistingProcessor {
// rewrite cardinality to alternatives
// A? B -> A B | B
// A* B -> A+ B | B -> A B (see above)
// TODO: what if B is empty?
// we need a clone of the element because we need to set the cardinality without changing the
// original syntax tree
@ -216,6 +238,7 @@ public class HoistingProcessor {
if (Token.isToken(path)) {
return true;
} else if (isParserRuleCall(path)) {
// can not be self recursive since ANTLR uses LL(*) and therefore does not support left recursion
return pathHasToken(((RuleCall) path).getRule().getAlternatives());
} else if (path instanceof Assignment) {
return pathHasToken(((Assignment) path).getTerminal());
@ -285,8 +308,8 @@ public class HoistingProcessor {
} else if (element instanceof JavaAction) {
return HoistingGuard.action();
} else if (element instanceof UnorderedGroup) {
// TODO: No support for Unordered Groups yet.
throw new UnsupportedOperationException("unordered groups are not yet supported");
// TODO: maybe add warning and return unguarded
throw new UnsupportedOperationException("unordered groups are only supported in groups");
} else if (element instanceof Assignment) {
return findGuardForElement(((Assignment) element).getTerminal());
} else {