pegjs/lib/compiler/passes/remove-proxy-rules.js
David Majda 6fa8ad63f9 Replace some functions with arrow functions
Because arrow functions work rather differently than normal functions (a
bad design mistake if you ask me), I decided to be conservative with the
conversion.

I converted:

  * event handlers
  * callbacks
  * arguments to Array.prototype.map & co.
  * small standalone lambda functions

I didn't convert:

  * functions assigned to object literal properties (the new shorthand
    syntax would be better here)
  * functions passed to "describe", "it", etc. in specs (because Jasmine
    relies on dynamic "this")

See #442.
2016-09-12 16:07:43 +02:00

43 lines
924 B
JavaScript

"use strict";
let arrays = require("../../utils/arrays"),
visitor = require("../visitor");
/*
* Removes proxy rules -- that is, rules that only delegate to other rule.
*/
function removeProxyRules(ast, options) {
function isProxyRule(node) {
return node.type === "rule" && node.expression.type === "rule_ref";
}
function replaceRuleRefs(ast, from, to) {
let replace = visitor.build({
rule_ref: function(node) {
if (node.name === from) {
node.name = to;
}
}
});
replace(ast);
}
let indices = [];
ast.rules.forEach((rule, i) => {
if (isProxyRule(rule)) {
replaceRuleRefs(ast, rule.name, rule.expression.name);
if (!arrays.contains(options.allowedStartRules, rule.name)) {
indices.push(i);
}
}
});
indices.reverse();
indices.forEach(i => { ast.rules.splice(i, 1); });
}
module.exports = removeProxyRules;