58 lines
2 KiB
JavaScript
58 lines
2 KiB
JavaScript
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/**
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* @fileoverview Define the cursor which iterates tokens and comments in reverse.
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* @author Toru Nagashima
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*/
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"use strict";
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//------------------------------------------------------------------------------
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// Requirements
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//------------------------------------------------------------------------------
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const Cursor = require("./cursor");
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const utils = require("./utils");
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//------------------------------------------------------------------------------
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// Exports
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//------------------------------------------------------------------------------
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/**
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* The cursor which iterates tokens and comments in reverse.
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*/
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module.exports = class BackwardTokenCommentCursor extends Cursor {
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/**
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* Initializes this cursor.
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* @param {Token[]} tokens The array of tokens.
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* @param {Comment[]} comments The array of comments.
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* @param {Object} indexMap The map from locations to indices in `tokens`.
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* @param {number} startLoc The start location of the iteration range.
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* @param {number} endLoc The end location of the iteration range.
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*/
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constructor(tokens, comments, indexMap, startLoc, endLoc) {
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super();
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this.tokens = tokens;
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this.comments = comments;
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this.tokenIndex = utils.getLastIndex(tokens, indexMap, endLoc);
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this.commentIndex = utils.search(comments, endLoc) - 1;
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this.border = startLoc;
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}
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/** @inheritdoc */
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moveNext() {
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const token = (this.tokenIndex >= 0) ? this.tokens[this.tokenIndex] : null;
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const comment = (this.commentIndex >= 0) ? this.comments[this.commentIndex] : null;
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if (token && (!comment || token.range[1] > comment.range[1])) {
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this.current = token;
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this.tokenIndex -= 1;
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} else if (comment) {
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this.current = comment;
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this.commentIndex -= 1;
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} else {
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this.current = null;
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}
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return Boolean(this.current) && (this.border === -1 || this.current.range[0] >= this.border);
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}
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};
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