mirror of
https://github.com/Smaug123/KaTeX
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8c55aed39a
* Introduce MacroExpander The job of the MacroExpander is turning a stream of possibly expandable tokens, as obtained from the Lexer, into a stream of non-expandable tokens (in KaTeX, even though they may well be expandable in TeX) which can be processed by the Parser. The challenge here is that we don't have mode-specific lexer implementations any more, so we need to do everything on the token level, including reassembly of sizes and colors. * Make macros available in development server Now one can specify macro definitions like \foo=bar as part of the query string and use these macros in the formula being typeset. * Add tests for macro expansions * Handle end of input in special groups This avoids an infinite loop if input ends prematurely. * Simplify parseSpecialGroup The parseSpecialGroup methos now returns a single token spanning the whole special group, and leaves matching that string against a suitable regular expression to whoever is calling the method. Suggested by @cbreeden. * Incorporate review suggestions Add improvements suggested by Kevin Barabash during review. * Input range sanity checks Ensure that both tokens of a token range come from the same lexer, and that the range has a non-negative length. * Improved wording of two comments
65 lines
2.0 KiB
JavaScript
65 lines
2.0 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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* If possible, a caller should provide a Token or ParseNode with information
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* about where in the source string the problem occurred.
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*
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* @param {string} message The error message
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* @param {(Token|ParseNode)=} token An object providing position information
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*/
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function ParseError(message, token) {
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var error = "KaTeX parse error: " + message;
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var start;
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var end;
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if (token && token.lexer && token.start <= token.end) {
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// If we have the input and a position, make the error a bit fancier
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// Get the input
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var input = token.lexer.input;
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// Prepend some information
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start = token.start;
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end = token.end;
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if (start === input.length) {
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error += " at end of input: ";
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} else {
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error += " at position " + (start + 1) + ": ";
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}
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// Underline token in question using combining underscores
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var underlined = input.slice(start, end).replace(/[^]/g, "$&\u0332");
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// Extract some context from the input and add it to the error
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var left;
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if (start > 15) {
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left = "…" + input.slice(start - 15, start);
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} else {
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left = input.slice(0, start);
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}
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var right;
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if (end + 15 < input.length) {
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right = input.slice(end, end + 15) + "…";
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} else {
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right = input.slice(end);
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}
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error += left + underlined + right;
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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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self.position = start;
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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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