f63af87f17
Summary: Add comments everywhere! Also fix some small bugs like using Style.id instead of Style.size, and rename some variables to be more descriptive. Fixes #22 Test Plan: - Make sure the huxley screenshots didn't change - Make sure the tests still pass Reviewers: alpert Reviewed By: alpert Differential Revision: http://phabricator.khanacademy.org/D13158
39 lines
1.3 KiB
JavaScript
39 lines
1.3 KiB
JavaScript
/**
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* This is the ParseError class, which is the main error thrown by KaTeX
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* functions when something has gone wrong. This is used to distinguish internal
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* errors from errors in the expression that the user provided.
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*/
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function ParseError(message, lexer, position) {
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var error = "KaTeX parse error: " + message;
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if (lexer !== undefined && position !== undefined) {
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// If we have the input and a position, make the error a bit fancier
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// Prepend some information
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error += " at position " + position + ": ";
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// Get the input
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var input = lexer._input;
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// Insert a combining underscore at the correct position
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input = input.slice(0, position) + "\u0332" +
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input.slice(position);
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// Extract some context from the input and add it to the error
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var begin = Math.max(0, position - 15);
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var end = position + 15;
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error += input.slice(begin, end);
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}
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// Some hackery to make ParseError a prototype of Error
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// See http://stackoverflow.com/a/8460753
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var self = new Error(error);
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self.name = "ParseError";
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self.__proto__ = ParseError.prototype;
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return self;
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}
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// More hackery
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ParseError.prototype.__proto__ = Error.prototype;
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module.exports = ParseError;
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