2 * Copyright (c) 2018 Pantheon Technologies, s.r.o. All rights reserved.
4 * This program and the accompanying materials are made available under the
5 * terms of the Eclipse Public License v1.0 which accompanies this distribution,
6 * and is available at http://www.eclipse.org/legal/epl-v10.html
8 package org.opendaylight.yangtools.yang.xpath.impl;
10 import static com.google.common.base.Preconditions.checkArgument;
11 import static com.google.common.base.Verify.verify;
12 import static com.google.common.base.Verify.verifyNotNull;
13 import static java.util.Objects.requireNonNull;
14 import static org.opendaylight.yangtools.yang.xpath.impl.ParseTreeUtils.getChild;
15 import static org.opendaylight.yangtools.yang.xpath.impl.ParseTreeUtils.illegalShape;
16 import static org.opendaylight.yangtools.yang.xpath.impl.ParseTreeUtils.verifyAtLeastChildren;
17 import static org.opendaylight.yangtools.yang.xpath.impl.ParseTreeUtils.verifyChildCount;
18 import static org.opendaylight.yangtools.yang.xpath.impl.ParseTreeUtils.verifyTerminal;
19 import static org.opendaylight.yangtools.yang.xpath.impl.ParseTreeUtils.verifyToken;
20 import static org.opendaylight.yangtools.yang.xpath.impl.ParseTreeUtils.verifyTree;
22 import com.google.common.collect.ImmutableList;
23 import com.google.common.collect.Iterators;
24 import com.google.common.collect.Maps;
25 import java.util.ArrayDeque;
26 import java.util.ArrayList;
27 import java.util.Arrays;
28 import java.util.Deque;
29 import java.util.Iterator;
30 import java.util.LinkedHashSet;
31 import java.util.List;
33 import java.util.Optional;
35 import javax.xml.xpath.XPathExpressionException;
36 import org.antlr.v4.runtime.CharStreams;
37 import org.antlr.v4.runtime.CommonTokenStream;
38 import org.antlr.v4.runtime.ParserRuleContext;
39 import org.antlr.v4.runtime.tree.ParseTree;
40 import org.antlr.v4.runtime.tree.TerminalNode;
41 import org.opendaylight.yangtools.yang.common.QName;
42 import org.opendaylight.yangtools.yang.common.QNameModule;
43 import org.opendaylight.yangtools.yang.common.QualifiedQName;
44 import org.opendaylight.yangtools.yang.common.UnqualifiedQName;
45 import org.opendaylight.yangtools.yang.common.YangConstants;
46 import org.opendaylight.yangtools.yang.common.YangNamespaceContext;
47 import org.opendaylight.yangtools.yang.common.YangVersion;
48 import org.opendaylight.yangtools.yang.xpath.antlr.xpathLexer;
49 import org.opendaylight.yangtools.yang.xpath.antlr.xpathParser;
50 import org.opendaylight.yangtools.yang.xpath.antlr.xpathParser.AbbreviatedStepContext;
51 import org.opendaylight.yangtools.yang.xpath.antlr.xpathParser.AbsoluteLocationPathNorootContext;
52 import org.opendaylight.yangtools.yang.xpath.antlr.xpathParser.AdditiveExprContext;
53 import org.opendaylight.yangtools.yang.xpath.antlr.xpathParser.AndExprContext;
54 import org.opendaylight.yangtools.yang.xpath.antlr.xpathParser.AxisSpecifierContext;
55 import org.opendaylight.yangtools.yang.xpath.antlr.xpathParser.EqualityExprContext;
56 import org.opendaylight.yangtools.yang.xpath.antlr.xpathParser.ExprContext;
57 import org.opendaylight.yangtools.yang.xpath.antlr.xpathParser.FilterExprContext;
58 import org.opendaylight.yangtools.yang.xpath.antlr.xpathParser.FunctionCallContext;
59 import org.opendaylight.yangtools.yang.xpath.antlr.xpathParser.FunctionNameContext;
60 import org.opendaylight.yangtools.yang.xpath.antlr.xpathParser.LocationPathContext;
61 import org.opendaylight.yangtools.yang.xpath.antlr.xpathParser.MultiplicativeExprContext;
62 import org.opendaylight.yangtools.yang.xpath.antlr.xpathParser.NCNameContext;
63 import org.opendaylight.yangtools.yang.xpath.antlr.xpathParser.NameTestContext;
64 import org.opendaylight.yangtools.yang.xpath.antlr.xpathParser.NodeTestContext;
65 import org.opendaylight.yangtools.yang.xpath.antlr.xpathParser.OrExprContext;
66 import org.opendaylight.yangtools.yang.xpath.antlr.xpathParser.PathExprNoRootContext;
67 import org.opendaylight.yangtools.yang.xpath.antlr.xpathParser.PredicateContext;
68 import org.opendaylight.yangtools.yang.xpath.antlr.xpathParser.PrimaryExprContext;
69 import org.opendaylight.yangtools.yang.xpath.antlr.xpathParser.QNameContext;
70 import org.opendaylight.yangtools.yang.xpath.antlr.xpathParser.RelationalExprContext;
71 import org.opendaylight.yangtools.yang.xpath.antlr.xpathParser.RelativeLocationPathContext;
72 import org.opendaylight.yangtools.yang.xpath.antlr.xpathParser.StepContext;
73 import org.opendaylight.yangtools.yang.xpath.antlr.xpathParser.UnaryExprNoRootContext;
74 import org.opendaylight.yangtools.yang.xpath.antlr.xpathParser.UnionExprNoRootContext;
75 import org.opendaylight.yangtools.yang.xpath.antlr.xpathParser.VariableReferenceContext;
76 import org.opendaylight.yangtools.yang.xpath.api.YangBinaryOperator;
77 import org.opendaylight.yangtools.yang.xpath.api.YangBooleanConstantExpr;
78 import org.opendaylight.yangtools.yang.xpath.api.YangExpr;
79 import org.opendaylight.yangtools.yang.xpath.api.YangFilterExpr;
80 import org.opendaylight.yangtools.yang.xpath.api.YangFunction;
81 import org.opendaylight.yangtools.yang.xpath.api.YangFunctionCallExpr;
82 import org.opendaylight.yangtools.yang.xpath.api.YangLiteralExpr;
83 import org.opendaylight.yangtools.yang.xpath.api.YangLocationPath;
84 import org.opendaylight.yangtools.yang.xpath.api.YangLocationPath.AxisStep;
85 import org.opendaylight.yangtools.yang.xpath.api.YangLocationPath.QNameStep;
86 import org.opendaylight.yangtools.yang.xpath.api.YangLocationPath.ResolvedQNameStep;
87 import org.opendaylight.yangtools.yang.xpath.api.YangLocationPath.Step;
88 import org.opendaylight.yangtools.yang.xpath.api.YangNaryExpr;
89 import org.opendaylight.yangtools.yang.xpath.api.YangNaryOperator;
90 import org.opendaylight.yangtools.yang.xpath.api.YangNegateExpr;
91 import org.opendaylight.yangtools.yang.xpath.api.YangNumberExpr;
92 import org.opendaylight.yangtools.yang.xpath.api.YangPathExpr;
93 import org.opendaylight.yangtools.yang.xpath.api.YangVariableReferenceExpr;
94 import org.opendaylight.yangtools.yang.xpath.api.YangXPathAxis;
95 import org.opendaylight.yangtools.yang.xpath.api.YangXPathExpression;
96 import org.opendaylight.yangtools.yang.xpath.api.YangXPathMathMode;
97 import org.opendaylight.yangtools.yang.xpath.api.YangXPathMathSupport;
98 import org.opendaylight.yangtools.yang.xpath.api.YangXPathNodeType;
99 import org.opendaylight.yangtools.yang.xpath.api.YangXPathParser;
102 * ANTLR-based XPath parser. Uses {@code xpath.g4} ANTLR grammar.
104 * @author Robert Varga
106 abstract class AntlrXPathParser implements YangXPathParser {
107 static class Base extends AntlrXPathParser {
108 Base(final YangXPathMathMode mathMode) {
113 public YangXPathExpression parseExpression(final String xpath) throws XPathExpressionException {
114 final ParseExprResult result = parseExpr(xpath);
115 return new AntlrYangXPathExpression.Base(mathMode, result.minimumYangVersion, result.expression, xpath);
119 QNameStep createStep(final YangXPathAxis axis, final String localName,
120 final List<YangExpr> predicates) {
121 return axis.asStep(UnqualifiedQName.of(localName).intern(), predicates);
125 QNameStep createStep(final YangXPathAxis axis, final String prefix, final String localName,
126 final List<YangExpr> predicates) {
127 return axis.asStep(QualifiedQName.of(prefix, localName).intern(), predicates);
131 QName createQName(final String localName) {
132 throw new UnsupportedOperationException();
136 QName createQName(final String prefix, final String localName) {
137 throw new UnsupportedOperationException();
141 static class Qualified extends Base implements QualifiedBound {
142 final YangNamespaceContext namespaceContext;
144 Qualified(final YangXPathMathMode mathMode, final YangNamespaceContext namespaceContext) {
146 this.namespaceContext = requireNonNull(namespaceContext);
150 public YangXPathExpression.QualifiedBound parseExpression(final String xpath) throws XPathExpressionException {
151 final ParseExprResult result = parseExpr(xpath);
152 return new AntlrYangXPathExpression.Qualified(mathMode, result.minimumYangVersion, result.expression, xpath,
157 final QName createQName(final String prefix, final String localName) {
158 return namespaceContext.createQName(prefix, localName);
162 ResolvedQNameStep createStep(final YangXPathAxis axis, final String prefix, final String localName,
163 final List<YangExpr> predicates) {
164 return axis.asStep(createQName(prefix, localName), predicates);
168 static final class Unqualified extends Qualified implements UnqualifiedBound {
169 private final QNameModule defaultNamespace;
171 Unqualified(final YangXPathMathMode mathMode, final YangNamespaceContext namespaceContext,
172 final QNameModule defaultNamespace) {
173 super(mathMode, namespaceContext);
174 this.defaultNamespace = requireNonNull(defaultNamespace);
178 public YangXPathExpression.UnqualifiedBound parseExpression(final String xpath)
179 throws XPathExpressionException {
180 final ParseExprResult result = parseExpr(xpath);
182 return new AntlrYangXPathExpression.Unqualified(mathMode, result.minimumYangVersion, result.expression,
183 xpath, namespaceContext, defaultNamespace);
187 QName createQName(final String localName) {
188 return QName.create(defaultNamespace, localName);
192 ResolvedQNameStep createStep(final YangXPathAxis axis, final String localName,
193 final List<YangExpr> predicates) {
194 return axis.asStep(QName.create(defaultNamespace, localName), predicates);
198 private static final class ParseExprResult {
199 final YangVersion minimumYangVersion;
200 final YangExpr expression;
202 ParseExprResult(final YangVersion minimumYangVersion, final YangExpr expression) {
203 this.minimumYangVersion = requireNonNull(minimumYangVersion);
204 this.expression = requireNonNull(expression);
208 private static final Map<String, YangBinaryOperator> BINARY_OPERATORS = Maps.uniqueIndex(
209 Arrays.asList(YangBinaryOperator.values()), YangBinaryOperator::toString);
210 private static final Map<String, YangXPathNodeType> NODE_TYPES = Maps.uniqueIndex(Arrays.asList(
211 YangXPathNodeType.values()), YangXPathNodeType::toString);
212 private static final Map<String, YangXPathAxis> XPATH_AXES = Maps.uniqueIndex(Arrays.asList(YangXPathAxis.values()),
213 YangXPathAxis::toString);
214 private static final Map<QName, YangFunction> YANG_FUNCTIONS = Maps.uniqueIndex(Arrays.asList(
215 YangFunction.values()), YangFunction::getIdentifier);
217 // Cached for checks in hot path
218 private static final AxisStep SELF_STEP = YangXPathAxis.SELF.asStep();
220 final YangXPathMathMode mathMode;
221 private final YangXPathMathSupport mathSupport;
222 private final FunctionSupport functionSupport;
224 private YangVersion minimumYangVersion = YangVersion.VERSION_1;
226 AntlrXPathParser(final YangXPathMathMode mathMode) {
227 this.mathMode = requireNonNull(mathMode);
228 this.mathSupport = mathMode.getSupport();
229 this.functionSupport = new FunctionSupport(mathSupport);
232 abstract QName createQName(String localName);
234 abstract QName createQName(String prefix, String localName);
236 abstract QNameStep createStep(YangXPathAxis axis, String localName, List<YangExpr> predicates);
238 abstract QNameStep createStep(YangXPathAxis axis, String prefix, String localName, List<YangExpr> predicates);
240 private QNameStep createStep(final YangXPathAxis axis, final QNameContext expr, final List<YangExpr> predicates) {
241 switch (expr.getChildCount()) {
243 return createStep(axis, getChild(expr, NCNameContext.class, 0).getText(), predicates);
245 return createStep(axis, getChild(expr, NCNameContext.class, 0).getText(),
246 getChild(expr, NCNameContext.class, 2).getText(), predicates);
248 throw illegalShape(expr);
252 @SuppressWarnings("checkstyle:illegalCatch")
253 final ParseExprResult parseExpr(final String xpath) throws XPathExpressionException {
254 // Create a parser and disconnect it from console error output
255 final xpathLexer lexer = new xpathLexer(CharStreams.fromString(xpath));
256 final xpathParser parser = new xpathParser(new CommonTokenStream(lexer));
258 final CapturingErrorListener listener = new CapturingErrorListener();
259 lexer.removeErrorListeners();
260 lexer.addErrorListener(listener);
261 parser.removeErrorListeners();
262 parser.addErrorListener(listener);
263 final ExprContext antlr = parser.main().expr();
264 listener.reportError();
266 // Reset our internal context
267 minimumYangVersion = YangVersion.VERSION_1;
271 expr = parseExpr(antlr);
272 } catch (RuntimeException e) {
273 throw new XPathExpressionException(e);
275 return new ParseExprResult(minimumYangVersion, expr);
279 * Parse and simplify an XPath expression in {@link ExprContext} representation.
281 * @param ctx Current parsing context
282 * @param expr ANTLR ExprContext
283 * @return A {@link YangExpr}
284 * @throws NullPointerException if {@code expr} is null
285 * @throws IllegalArgumentException if {@code expr} references an unbound prefix
287 private YangExpr parseExpr(final ExprContext expr) {
288 final OrExprContext or = expr.orExpr();
289 final int size = or.getChildCount();
291 return parseAnd(getChild(or, AndExprContext.class, 0));
293 final List<YangExpr> tmp = new ArrayList<>((size + 1) / 2);
294 for (int i = 0; i < size; i += 2) {
295 tmp.add(parseAnd(getChild(or, AndExprContext.class, i)));
297 return YangNaryOperator.OR.exprWith(tmp);
300 private YangExpr parseAdditive(final AdditiveExprContext expr) {
301 final Iterator<ParseTree> it = expr.children.iterator();
302 final YangExpr first = parseMultiplicative(nextContext(it, MultiplicativeExprContext.class));
303 return it.hasNext() ? parseAdditiveExpr(first, it) : first;
306 private YangExpr parseAnd(final AndExprContext expr) {
307 final int size = expr.getChildCount();
309 return parseEquality(getChild(expr, EqualityExprContext.class, 0));
311 final List<YangExpr> tmp = new ArrayList<>((size + 1) / 2);
312 for (int i = 0; i < size; i += 2) {
313 tmp.add(parseEquality(getChild(expr, EqualityExprContext.class, i)));
315 return YangNaryOperator.AND.exprWith(tmp);
318 private YangExpr parseEquality(final EqualityExprContext expr) {
319 final Iterator<ParseTree> it = expr.children.iterator();
320 final YangExpr first = parseRelational(nextContext(it, RelationalExprContext.class));
321 return it.hasNext() ? parseEqualityExpr(first, it) : first;
324 private YangExpr parseFilter(final FilterExprContext expr) {
325 final Iterator<ParseTree> it = expr.children.iterator();
326 final YangExpr first = parsePrimary(nextContext(it, PrimaryExprContext.class));
327 return it.hasNext() ? YangFilterExpr.of(first, ImmutableList.copyOf(Iterators.transform(it,
328 tree -> parsePredicate(verifyTree(PredicateContext.class, tree)))))
332 private YangExpr parseFunctionCall(final FunctionCallContext expr) {
333 // We are mapping functions to RFC7950 YIN namespace, to keep us consistent with type/statement definitions
335 final FunctionNameContext name = getChild(expr, FunctionNameContext.class, 0);
337 switch (name.getChildCount()) {
339 parsed = QName.create(YangConstants.RFC6020_YIN_MODULE, name.getChild(0).getText());
342 parsed = createQName(name.getChild(0).getText(), name.getChild(2).getText());
345 throw illegalShape(name);
348 final List<YangExpr> args = expr.expr().stream().map(this::parseExpr).collect(ImmutableList.toImmutableList());
349 final YangFunction func = YANG_FUNCTIONS.get(parsed);
351 if (minimumYangVersion.compareTo(func.getYangVersion()) < 0) {
352 minimumYangVersion = func.getYangVersion();
354 return functionSupport.functionToExpr(func, args);
357 checkArgument(!YangConstants.RFC6020_YIN_MODULE.equals(parsed.getModule()), "Unknown default function %s",
359 return YangFunctionCallExpr.of(parsed, args);
362 private YangLocationPath parseLocationPath(final LocationPathContext expr) {
363 verifyChildCount(expr, 1);
364 final ParseTree first = expr.getChild(0);
365 if (first instanceof RelativeLocationPathContext) {
366 return YangLocationPath.relative(parseLocationPathSteps((RelativeLocationPathContext) first));
369 final AbsoluteLocationPathNorootContext abs = verifyTree(AbsoluteLocationPathNorootContext.class, first);
370 verifyChildCount(abs, 2);
372 final Deque<Step> steps = parseLocationPathSteps(getChild(abs, RelativeLocationPathContext.class, 1));
373 parseStepShorthand(abs.getChild(0)).ifPresent(steps::addFirst);
375 return YangLocationPath.absolute(steps);
378 private YangExpr parseMultiplicative(final MultiplicativeExprContext expr) {
379 final ParseTree first = expr.getChild(0);
381 if (first instanceof UnaryExprNoRootContext) {
382 left = parseUnary((UnaryExprNoRootContext) first);
384 left = YangLocationPath.root();
386 if (expr.getChildCount() == 1) {
390 verifyChildCount(expr, 3);
391 final YangBinaryOperator operator = parseOperator(expr.getChild(1));
392 final YangExpr right = parseMultiplicative(getChild(expr, MultiplicativeExprContext.class, 2));
393 final Optional<YangExpr> simple = simplifyNumbers(operator, left, right);
394 return simple.isPresent() ? simple.get() : operator.exprWith(left, right);
397 private YangExpr parsePathExpr(final PathExprNoRootContext expr) {
398 final ParseTree first = expr.getChild(0);
399 if (first instanceof LocationPathContext) {
400 return parseLocationPath((LocationPathContext) first);
403 final YangExpr filter = parseFilter(verifyTree(FilterExprContext.class, first));
404 if (expr.getChildCount() == 1) {
408 verifyChildCount(expr, 3);
409 final Deque<Step> steps = parseLocationPathSteps(getChild(expr, RelativeLocationPathContext.class, 2));
410 parseStepShorthand(expr.getChild(1)).ifPresent(steps::addFirst);
411 return YangPathExpr.of(filter, YangLocationPath.relative(steps));
414 private YangExpr parsePredicate(final PredicateContext expr) {
415 verifyChildCount(expr, 3);
416 return parseExpr(getChild(expr, ExprContext.class, 1));
419 private YangExpr parsePrimary(final PrimaryExprContext expr) {
420 if (expr.getChildCount() == 3) {
421 return parseExpr(getChild(expr, ExprContext.class, 1));
424 verifyChildCount(expr, 1);
425 final ParseTree first = expr.getChild(0);
426 if (first instanceof TerminalNode) {
427 return parseTerminal((TerminalNode) first);
429 if (first instanceof FunctionCallContext) {
430 return parseFunctionCall((FunctionCallContext) first);
432 if (first instanceof VariableReferenceContext) {
433 return YangVariableReferenceExpr.of(parseQName(((VariableReferenceContext) first).qName()));
435 throw illegalShape(first);
438 private YangExpr parseRelational(final RelationalExprContext expr) {
439 final Iterator<ParseTree> it = expr.children.iterator();
440 final YangExpr first = parseAdditive(nextContext(it, AdditiveExprContext.class));
441 return it.hasNext() ? parseRelationalExpr(first, it) : first;
444 private Deque<Step> parseLocationPathSteps(final RelativeLocationPathContext expr) {
445 final Deque<Step> steps = new ArrayDeque<>(expr.getChildCount());
446 final Iterator<ParseTree> it = expr.children.iterator();
447 addNotSelfStep(steps, parseStep(nextContext(it, StepContext.class)));
449 while (it.hasNext()) {
450 parseStepShorthand(it.next()).ifPresent(steps::add);
452 // Parse step and add it if it's not SELF_STEP
453 addNotSelfStep(steps, parseStep(nextContext(it, StepContext.class)));
459 private static void addNotSelfStep(final Deque<Step> steps, final Step step) {
460 if (!SELF_STEP.equals(step)) {
465 private YangExpr parseTerminal(final TerminalNode term) {
466 final String text = term.getText();
467 switch (term.getSymbol().getType()) {
468 case xpathParser.Literal:
469 // We have to strip quotes
470 return YangLiteralExpr.of(text.substring(1, text.length() - 1));
471 case xpathParser.Number:
472 return mathSupport.createNumber(text);
474 throw illegalShape(term);
478 private YangExpr parseUnary(final UnaryExprNoRootContext expr) {
479 // any number of '-' and an union expr
480 final int size = verifyAtLeastChildren(expr, 1);
481 final YangExpr ret = parseUnion(getChild(expr, UnionExprNoRootContext.class, size - 1));
483 // Even number of '-' tokens cancel out
486 return ret instanceof YangNumberExpr ? mathSupport.negateNumber((YangNumberExpr) ret) : YangNegateExpr.of(ret);
489 private YangExpr parseUnion(final UnionExprNoRootContext expr) {
490 final ParseTree first = expr.getChild(0);
492 if (first instanceof PathExprNoRootContext) {
493 path = parsePathExpr((PathExprNoRootContext) first);
494 if (expr.getChildCount() == 1) {
498 path = YangLocationPath.root();
501 verifyChildCount(expr, 3);
502 final YangExpr union = parseUnion(getChild(expr, UnionExprNoRootContext.class, 2));
504 // Deduplicate expressions so we do not perform useless unioning
505 final Set<YangExpr> expressions = new LinkedHashSet<>();
506 expressions.add(path);
507 if (union instanceof YangNaryExpr) {
508 // If the result is a union expression, integrate it into this expression
509 final YangNaryExpr nary = (YangNaryExpr) union;
510 if (nary.getOperator() == YangNaryOperator.UNION) {
511 expressions.addAll(nary.getExpressions());
513 expressions.add(union);
516 expressions.add(union);
519 return YangNaryOperator.UNION.exprWith(expressions);
522 private YangExpr parseAdditiveExpr(final YangExpr left, final Iterator<ParseTree> it) {
525 final YangBinaryOperator operator = nextOperator(it);
526 final YangExpr right = parseMultiplicative(nextContext(it, MultiplicativeExprContext.class));
527 final Optional<YangExpr> simple = simplifyNumbers(operator, ret, right);
528 ret = simple.isPresent() ? simple.get() : operator.exprWith(ret, right);
529 } while (it.hasNext());
534 private Optional<YangExpr> simplifyNumbers(final YangBinaryOperator operator, final YangExpr left,
535 final YangExpr right) {
536 if (left instanceof YangNumberExpr && right instanceof YangNumberExpr) {
537 // Constant folding on numbers -- precision plays a role here
538 return mathSupport.tryEvaluate(operator, (YangNumberExpr)left, (YangNumberExpr)right);
540 return Optional.empty();
543 private YangExpr parseEqualityExpr(final YangExpr left, final Iterator<ParseTree> it) {
546 final YangBinaryOperator operator = nextOperator(it);
547 final YangExpr right = parseRelational(nextContext(it, RelationalExprContext.class));
549 if (left.equals(right)) {
550 // Constant folding on expression level: equal expressions are result in equal results
553 return YangBooleanConstantExpr.TRUE;
555 return YangBooleanConstantExpr.FALSE;
561 final Optional<YangExpr> simple = simplifyNumbers(operator, ret, right);
562 ret = simple.isPresent() ? simple.get() : operator.exprWith(ret, right);
563 } while (it.hasNext());
568 private YangExpr parseRelationalExpr(final YangExpr left, final Iterator<ParseTree> it) {
571 final YangBinaryOperator operator = nextOperator(it);
572 final YangExpr right = parseAdditive(nextContext(it, AdditiveExprContext.class));
573 final Optional<YangExpr> simple = simplifyNumbers(operator, ret, right);
574 ret = simple.isPresent() ? simple.get() : operator.exprWith(ret, right);
575 } while (it.hasNext());
580 private Step parseStep(final StepContext expr) {
581 if (expr.getChildCount() == 1) {
582 final AbbreviatedStepContext abbrev = getChild(expr, AbbreviatedStepContext.class, 0);
583 verifyChildCount(abbrev, 1);
584 switch (getTerminalType(abbrev, 0)) {
585 case xpathParser.DOT:
586 return YangXPathAxis.SELF.asStep();
587 case xpathParser.DOTDOT:
588 return YangXPathAxis.PARENT.asStep();
590 throw illegalShape(abbrev);
594 final int size = verifyAtLeastChildren(expr, 2);
595 final List<YangExpr> predicates = new ArrayList<>(size - 2);
596 for (int i = 2; i < size; ++i) {
597 predicates.add(parsePredicate(getChild(expr, PredicateContext.class, i)));
600 final YangXPathAxis axis = parseAxis(getChild(expr, AxisSpecifierContext.class, 0));
601 final NodeTestContext nodeTest = getChild(expr, NodeTestContext.class, 1);
602 switch (nodeTest.getChildCount()) {
604 final NameTestContext nameChild = getChild(nodeTest, NameTestContext.class, 0);
605 final ParseTree first = nameChild.getChild(0);
606 if (first instanceof TerminalNode) {
607 verify(((TerminalNode) first).getSymbol().getType() == xpathParser.MUL);
608 return axis.asStep(predicates);
610 return createStep(axis, verifyTree(QNameContext.class, first), predicates);
612 return axis.asStep(parseNodeType(nodeTest.getChild(0)), predicates);
614 final String text = verifyToken(nodeTest, 2, xpathParser.Literal).getText();
615 return axis.asStep(text.substring(1, text.length() - 1), predicates);
617 throw illegalShape(nodeTest);
621 private static YangXPathAxis parseAxis(final AxisSpecifierContext expr) {
622 switch (expr.getChildCount()) {
624 return YangXPathAxis.CHILD;
626 verify(getTerminalType(expr, 0) == xpathParser.AT, "Unhandled axis specifier shape %s", expr);
627 return YangXPathAxis.ATTRIBUTE;
629 final String str = verifyTerminal(expr.getChild(0)).getText();
630 return verifyNotNull(XPATH_AXES.get(str), "Unhandled axis %s", str);
632 throw illegalShape(expr);
636 private QName parseQName(final QNameContext expr) {
637 switch (expr.getChildCount()) {
639 return createQName(getChild(expr, NCNameContext.class, 0).getText());
641 return createQName(getChild(expr, NCNameContext.class, 0).getText(),
642 getChild(expr, NCNameContext.class, 2).getText());
644 throw illegalShape(expr);
648 private static <T extends ParserRuleContext> T nextContext(final Iterator<ParseTree> it, final Class<T> type) {
649 return verifyTree(type, it.next());
652 private static YangBinaryOperator nextOperator(final Iterator<ParseTree> it) {
653 return parseOperator(it.next());
656 private static int getTerminalType(final ParseTree parent, final int offset) {
657 return verifyTerminal(parent.getChild(offset)).getSymbol().getType();
660 private static YangXPathNodeType parseNodeType(final ParseTree tree) {
661 final String str = verifyTerminal(tree).getText();
662 return verifyNotNull(NODE_TYPES.get(str), "Unhandled node type %s", str);
665 private static YangBinaryOperator parseOperator(final ParseTree tree) {
666 final String str = verifyTerminal(tree).getText();
667 return verifyNotNull(BINARY_OPERATORS.get(str), "Unhandled operator %s", str);
670 private static Optional<Step> parseStepShorthand(final ParseTree tree) {
671 switch (verifyTerminal(tree).getSymbol().getType()) {
672 case xpathParser.PATHSEP:
673 return Optional.empty();
674 case xpathParser.ABRPATH:
675 return Optional.of(YangXPathAxis.DESCENDANT_OR_SELF.asStep());
677 throw illegalShape(tree);