antlr4ts
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ANTLR 4 runtime for JavaScript written in Typescript
144 lines • 6.18 kB
JavaScript
;
/*!
* Copyright 2016 The ANTLR Project. All rights reserved.
* Licensed under the BSD-3-Clause license. See LICENSE file in the project root for license information.
*/
var __decorate = (this && this.__decorate) || function (decorators, target, key, desc) {
var c = arguments.length, r = c < 3 ? target : desc === null ? desc = Object.getOwnPropertyDescriptor(target, key) : desc, d;
if (typeof Reflect === "object" && typeof Reflect.decorate === "function") r = Reflect.decorate(decorators, target, key, desc);
else for (var i = decorators.length - 1; i >= 0; i--) if (d = decorators[i]) r = (c < 3 ? d(r) : c > 3 ? d(target, key, r) : d(target, key)) || r;
return c > 3 && r && Object.defineProperty(target, key, r), r;
};
var __param = (this && this.__param) || function (paramIndex, decorator) {
return function (target, key) { decorator(target, key, paramIndex); }
};
Object.defineProperty(exports, "__esModule", { value: true });
exports.AbstractParseTreeVisitor = void 0;
const Decorators_1 = require("../Decorators");
class AbstractParseTreeVisitor {
/**
* {@inheritDoc}
*
* The default implementation calls {@link ParseTree#accept} on the
* specified tree.
*/
visit(tree) {
return tree.accept(this);
}
/**
* {@inheritDoc}
*
* The default implementation initializes the aggregate result to
* {@link #defaultResult defaultResult()}. Before visiting each child, it
* calls {@link #shouldVisitNextChild shouldVisitNextChild}; if the result
* is `false` no more children are visited and the current aggregate
* result is returned. After visiting a child, the aggregate result is
* updated by calling {@link #aggregateResult aggregateResult} with the
* previous aggregate result and the result of visiting the child.
*
* The default implementation is not safe for use in visitors that modify
* the tree structure. Visitors that modify the tree should override this
* method to behave properly in respect to the specific algorithm in use.
*/
visitChildren(node) {
let result = this.defaultResult();
let n = node.childCount;
for (let i = 0; i < n; i++) {
if (!this.shouldVisitNextChild(node, result)) {
break;
}
let c = node.getChild(i);
let childResult = c.accept(this);
result = this.aggregateResult(result, childResult);
}
return result;
}
/**
* {@inheritDoc}
*
* The default implementation returns the result of
* {@link #defaultResult defaultResult}.
*/
visitTerminal(node) {
return this.defaultResult();
}
/**
* {@inheritDoc}
*
* The default implementation returns the result of
* {@link #defaultResult defaultResult}.
*/
visitErrorNode(node) {
return this.defaultResult();
}
/**
* Aggregates the results of visiting multiple children of a node. After
* either all children are visited or {@link #shouldVisitNextChild} returns
* `false`, the aggregate value is returned as the result of
* {@link #visitChildren}.
*
* The default implementation returns `nextResult`, meaning
* {@link #visitChildren} will return the result of the last child visited
* (or return the initial value if the node has no children).
*
* @param aggregate The previous aggregate value. In the default
* implementation, the aggregate value is initialized to
* {@link #defaultResult}, which is passed as the `aggregate` argument
* to this method after the first child node is visited.
* @param nextResult The result of the immediately preceeding call to visit
* a child node.
*
* @returns The updated aggregate result.
*/
aggregateResult(aggregate, nextResult) {
return nextResult;
}
/**
* This method is called after visiting each child in
* {@link #visitChildren}. This method is first called before the first
* child is visited; at that point `currentResult` will be the initial
* value (in the default implementation, the initial value is returned by a
* call to {@link #defaultResult}. This method is not called after the last
* child is visited.
*
* The default implementation always returns `true`, indicating that
* `visitChildren` should only return after all children are visited.
* One reason to override this method is to provide a "short circuit"
* evaluation option for situations where the result of visiting a single
* child has the potential to determine the result of the visit operation as
* a whole.
*
* @param node The {@link RuleNode} whose children are currently being
* visited.
* @param currentResult The current aggregate result of the children visited
* to the current point.
*
* @returns `true` to continue visiting children. Otherwise return
* `false` to stop visiting children and immediately return the
* current aggregate result from {@link #visitChildren}.
*/
shouldVisitNextChild(node, currentResult) {
return true;
}
}
__decorate([
Decorators_1.Override,
__param(0, Decorators_1.NotNull)
], AbstractParseTreeVisitor.prototype, "visit", null);
__decorate([
Decorators_1.Override,
__param(0, Decorators_1.NotNull)
], AbstractParseTreeVisitor.prototype, "visitChildren", null);
__decorate([
Decorators_1.Override,
__param(0, Decorators_1.NotNull)
], AbstractParseTreeVisitor.prototype, "visitTerminal", null);
__decorate([
Decorators_1.Override,
__param(0, Decorators_1.NotNull)
], AbstractParseTreeVisitor.prototype, "visitErrorNode", null);
__decorate([
__param(0, Decorators_1.NotNull)
], AbstractParseTreeVisitor.prototype, "shouldVisitNextChild", null);
exports.AbstractParseTreeVisitor = AbstractParseTreeVisitor;
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