36 lines
1.0 KiB
JavaScript
36 lines
1.0 KiB
JavaScript
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"use strict";
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var GrammarError = require("../../grammar-error"),
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asts = require("../asts"),
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visitor = require("../visitor");
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/*
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* Reports expressions that don't consume any input inside |*| or |+| in the
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* grammar, which prevents infinite loops in the generated parser.
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*/
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function reportInfiniteRepetition(ast) {
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var check = visitor.build({
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zero_or_more: function(node) {
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if (!asts.alwaysConsumesOnSuccess(ast, node.expression)) {
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throw new GrammarError(
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"Possible infinite loop when parsing (repetition used with an expression that may not consume any input).",
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node.location
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);
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}
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},
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one_or_more: function(node) {
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if (!asts.alwaysConsumesOnSuccess(ast, node.expression)) {
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throw new GrammarError(
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"Possible infinite loop when parsing (repetition used with an expression that may not consume any input).",
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node.location
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);
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}
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}
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});
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check(ast);
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}
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module.exports = reportInfiniteRepetition;
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