91 lines
		
	
	
		
			3.7 KiB
		
	
	
	
		
			JavaScript
		
	
	
	
	
	
			
		
		
	
	
			91 lines
		
	
	
		
			3.7 KiB
		
	
	
	
		
			JavaScript
		
	
	
	
	
	
/**
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 * @fileoverview Define 2 token factories; forward and backward.
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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 BackwardTokenCommentCursor = require("./backward-token-comment-cursor");
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const BackwardTokenCursor = require("./backward-token-cursor");
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const FilterCursor = require("./filter-cursor");
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const ForwardTokenCommentCursor = require("./forward-token-comment-cursor");
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const ForwardTokenCursor = require("./forward-token-cursor");
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const LimitCursor = require("./limit-cursor");
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const SkipCursor = require("./skip-cursor");
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//------------------------------------------------------------------------------
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// Helpers
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//------------------------------------------------------------------------------
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/**
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 * The cursor factory.
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 * @private
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 */
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class CursorFactory {
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    /**
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     * Initializes this cursor.
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     * @param {Function} TokenCursor The class of the cursor which iterates tokens only.
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     * @param {Function} TokenCommentCursor The class of the cursor which iterates the mix of tokens and comments.
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     */
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    constructor(TokenCursor, TokenCommentCursor) {
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        this.TokenCursor = TokenCursor;
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        this.TokenCommentCursor = TokenCommentCursor;
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    }
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    /**
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     * Creates a base cursor instance that can be decorated by createCursor.
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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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     * @param {boolean} includeComments The flag to iterate comments as well.
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     * @returns {Cursor} The created base cursor.
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     */
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    createBaseCursor(tokens, comments, indexMap, startLoc, endLoc, includeComments) {
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        const Cursor = includeComments ? this.TokenCommentCursor : this.TokenCursor;
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        return new Cursor(tokens, comments, indexMap, startLoc, endLoc);
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    }
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    /**
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     * Creates a cursor that iterates tokens with normalized options.
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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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     * @param {boolean} includeComments The flag to iterate comments as well.
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     * @param {Function|null} filter The predicate function to choose tokens.
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     * @param {number} skip The count of tokens the cursor skips.
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     * @param {number} count The maximum count of tokens the cursor iterates. Zero is no iteration for backward compatibility.
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     * @returns {Cursor} The created cursor.
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     */
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    createCursor(tokens, comments, indexMap, startLoc, endLoc, includeComments, filter, skip, count) {
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        let cursor = this.createBaseCursor(tokens, comments, indexMap, startLoc, endLoc, includeComments);
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        if (filter) {
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            cursor = new FilterCursor(cursor, filter);
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        }
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        if (skip >= 1) {
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            cursor = new SkipCursor(cursor, skip);
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        }
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        if (count >= 0) {
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            cursor = new LimitCursor(cursor, count);
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        }
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        return cursor;
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    }
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}
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//------------------------------------------------------------------------------
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// Exports
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//------------------------------------------------------------------------------
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exports.forward = new CursorFactory(ForwardTokenCursor, ForwardTokenCommentCursor);
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exports.backward = new CursorFactory(BackwardTokenCursor, BackwardTokenCommentCursor);
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