47 lines
1.3 KiB
JavaScript
47 lines
1.3 KiB
JavaScript
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/**
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* @author Toru Nagashima <https://github.com/mysticatea>
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* See LICENSE file in root directory for full license.
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*/
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"use strict"
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/**
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* Merge two visitors.
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* This function modifies `visitor1` directly to merge.
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* @param {Visitor} visitor1 The visitor which is assigned.
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* @param {Visitor} visitor2 The visitor which is assigning.
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* @returns {Visitor} `visitor1`.
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*/
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module.exports = function mergeVisitorsInPlace(visitor1, visitor2) {
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for (const key of Object.keys(visitor2)) {
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const handler1 = visitor1[key]
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const handler2 = visitor2[key]
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if (typeof handler1 === "function") {
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if (handler1._handlers) {
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handler1._handlers.push(handler2)
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} else {
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const handlers = [handler1, handler2]
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visitor1[key] = Object.assign(dispatch.bind(null, handlers), {
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_handlers: handlers,
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})
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}
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} else {
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visitor1[key] = handler2
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}
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}
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return visitor1
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}
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/**
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* Dispatch all given functions with a node.
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* @param {function[]} handlers The function list to call.
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* @param {Node} node The AST node to be handled.
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* @returns {void}
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*/
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function dispatch(handlers, node) {
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for (const h of handlers) {
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h(node)
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}
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}
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