private static boolean isPossibleEmptyAttrs(PsiElement attrs) {
if (!(attrs instanceof BnfParenExpression)) return false;
if (attrs.getFirstChild().getNode().getElementType() != BnfTypes.BNF_LEFT_BRACE) return false;
if (!(((BnfParenExpression) attrs).getExpression() instanceof BnfReferenceOrToken))
return false;
return isLastInRuleOrFree(attrs);
}
private static Collection<String> suggestKeywords(PsiElement position) {
TextRange posRange = position.getTextRange();
BnfFile posFile = (BnfFile) position.getContainingFile();
BnfRule statement = PsiTreeUtil.getTopmostParentOfType(position, BnfRule.class);
final TextRange range;
if (statement != null) {
range = new TextRange(statement.getTextRange().getStartOffset(), posRange.getStartOffset());
} else {
int offset = posRange.getStartOffset();
for (PsiElement cur = GrammarUtil.getDummyAwarePrevSibling(position);
cur != null;
cur = GrammarUtil.getDummyAwarePrevSibling(cur)) {
if (cur instanceof BnfAttrs) offset = cur.getTextRange().getEndOffset();
else if (cur instanceof BnfRule) offset = cur.getTextRange().getStartOffset();
else continue;
break;
}
range = new TextRange(offset, posRange.getStartOffset());
}
final String text =
range.isEmpty()
? CompletionInitializationContext.DUMMY_IDENTIFIER
: range.substring(posFile.getText());
PsiFile file =
PsiFileFactory.getInstance(posFile.getProject())
.createFileFromText("a.bnf", BnfLanguage.INSTANCE, text, true, false);
int completionOffset = posRange.getStartOffset() - range.getStartOffset();
GeneratedParserUtilBase.CompletionState state =
new GeneratedParserUtilBase.CompletionState(completionOffset) {
@Override
public String convertItem(Object o) {
// we do not have other keywords
return o instanceof String ? (String) o : null;
}
};
file.putUserData(GeneratedParserUtilBase.COMPLETION_STATE_KEY, state);
TreeUtil.ensureParsed(file.getNode());
return state.items;
}
private static boolean isLastInRuleOrFree(PsiElement element) {
PsiElement parent =
PsiTreeUtil.getParentOfType(
element, BnfRule.class, GeneratedParserUtilBase.DummyBlock.class);
if (parent instanceof GeneratedParserUtilBase.DummyBlock) return true;
if (!(parent instanceof BnfRule)) return false;
for (PsiElement cur = element, next = cur.getNextSibling();
next == null || next instanceof PsiComment || next instanceof PsiWhiteSpace;
cur = next, next = cur.getNextSibling()) {
if (next == null) {
PsiElement curParent = cur.getParent();
while (next == null && curParent != parent) {
next = curParent.getNextSibling();
curParent = curParent.getParent();
}
if (curParent == parent) return true;
next = PsiTreeUtil.getDeepestFirst(next);
}
}
return false;
}
