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29 lines
686 B
JavaScript
29 lines
686 B
JavaScript
"use strict";
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let GrammarError = require("../../grammar-error"),
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visitor = require("../visitor");
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/* Checks that each rule is defined only once. */
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function reportDuplicateRules(ast) {
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let rules = {};
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let check = visitor.build({
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rule: function(node) {
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if (rules.hasOwnProperty(node.name)) {
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throw new GrammarError(
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"Rule \"" + node.name + "\" is already defined "
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+ "at line " + rules[node.name].start.line + ", "
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+ "column " + rules[node.name].start.column + ".",
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node.location
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);
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}
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rules[node.name] = node.location;
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}
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});
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check(ast);
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}
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module.exports = reportDuplicateRules;
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