Make errors more informative
Make error messages from the lexing and parsing stages be a bit more helpful. If
provided with the input and a position, the error will display the error
position, and the nearby input with the error position underlined (yay combining
marks). Also, standardize the errors a bit (remove doubled "Error:" strings)
Test plan:
- Make sure the errors look totally sweet (before: {F15602}, after: {F15603})
- Trigger every error (that can be triggered) in Parser, Lexer, and buildTree
using the inputs:
`a^`
`a_`
`a^x^x`
`a_x_x`
`\color f`
`\blue `
`\Huge`
`\llap`
`\text`
`\dfrac`
`\dfrac{x}`
`\d`
`\blue{`
`\color{#f`
`{\Huge{x}}`
- See that the tests still work
Auditors: alpert
This commit is contained in:
Emily Eisenberg
parent
c22d8644cc
commit
e68cc472c6
4
Lexer.js
4
Lexer.js
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@ -80,7 +80,7 @@ Lexer.prototype._innerLex = function(pos, normals, ignoreWhitespace) {
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// We didn't match any of the tokens, so throw an error.
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throw new ParseError("Unexpected character: '" + input[0] +
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"' at position " + pos);
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"'", this, pos);
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}
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// A regex to match a CSS color (like #ffffff or BlueViolet)
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@ -101,7 +101,7 @@ Lexer.prototype._innerLexColor = function(pos) {
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}
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// We didn't match a color, so throw an error.
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throw new ParseError("Invalid color at position " + pos);
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throw new ParseError("Invalid color", this, pos);
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};
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// Lex a single token
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@ -1,5 +1,24 @@
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function ParseError(message) {
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var self = new Error("TeX parse error: " + message);
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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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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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68
Parser.js
68
Parser.js
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@ -24,10 +24,12 @@ function ParseNode(type, value, mode) {
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// Checks a result to make sure it has the right type, and throws an
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// appropriate error otherwise.
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var expect = function(result, type) {
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Parser.prototype.expect = function(result, type) {
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if (result.type !== type) {
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throw new ParseError(
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"Expected '" + type + "', got '" + result.type + "'");
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"Expected '" + type + "', got '" + result.type + "'",
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this.lexer, result.position
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);
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}
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};
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@ -48,7 +50,7 @@ Parser.prototype.parseInput = function(pos, mode) {
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var expression = this.parseExpression(pos, mode);
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// If we succeeded, make sure there's an EOF at the end
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var EOF = this.lexer.lex(expression.position, mode);
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expect(EOF, "EOF");
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this.expect(EOF, "EOF");
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return expression;
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};
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@ -73,7 +75,8 @@ Parser.prototype.parseExpression = function(pos, mode) {
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// Parses a superscript expression, like "^3"
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Parser.prototype.parseSuperscript = function(pos, mode) {
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if (mode !== "math") {
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throw new ParseError("Trying to parse superscript in non-math mode");
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throw new ParseError(
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"Trying to parse superscript in non-math mode", this.lexer, pos);
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}
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// Try to parse a "^" character
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@ -85,7 +88,8 @@ Parser.prototype.parseSuperscript = function(pos, mode) {
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return group;
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} else {
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// Throw an error if we didn't find a group
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throw new ParseError("Couldn't find group after '^'");
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throw new ParseError(
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"Couldn't find group after '^'", this.lexer, sup.position);
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}
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} else if (sup.type === "'") {
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var pos = sup.position;
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@ -99,7 +103,8 @@ Parser.prototype.parseSuperscript = function(pos, mode) {
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// Parses a subscript expression, like "_3"
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Parser.prototype.parseSubscript = function(pos, mode) {
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if (mode !== "math") {
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throw new ParseError("Trying to parse subscript in non-math mode");
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throw new ParseError(
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"Trying to parse subscript in non-math mode", this.lexer, pos);
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}
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// Try to parse a "_" character
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@ -111,7 +116,8 @@ Parser.prototype.parseSubscript = function(pos, mode) {
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return group;
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} else {
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// Throw an error if we didn't find a group
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throw new ParseError("Couldn't find group after '_'");
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throw new ParseError(
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"Couldn't find group after '_'", this.lexer, sub.position);
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}
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} else {
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return null;
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@ -146,7 +152,8 @@ Parser.prototype.parseAtom = function(pos, mode) {
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var node;
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if ((node = this.parseSuperscript(nextPos, mode))) {
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if (sup) {
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throw new ParseError("Parse error: Double superscript");
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throw new ParseError(
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"Double superscript", this.lexer, nextPos);
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}
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nextPos = node.position;
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sup = node.result;
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@ -154,7 +161,8 @@ Parser.prototype.parseAtom = function(pos, mode) {
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}
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if ((node = this.parseSubscript(nextPos, mode))) {
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if (sub) {
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throw new ParseError("Parse error: Double subscript");
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throw new ParseError(
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"Double subscript", this.lexer, nextPos);
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}
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nextPos = node.position;
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sub = node.result;
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@ -183,7 +191,7 @@ Parser.prototype.parseGroup = function(pos, mode) {
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var expression = this.parseExpression(start.position, mode);
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// Make sure we get a close brace
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var closeBrace = this.lexer.lex(expression.position, mode);
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expect(closeBrace, "}");
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this.expect(closeBrace, "}");
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return new ParseResult(
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new ParseNode("ordgroup", expression.result, mode),
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closeBrace.position);
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@ -202,14 +210,16 @@ Parser.prototype.parseColorGroup = function(pos, mode) {
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var color = this.lexer.lex(start.position, "color");
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// Make sure we get a close brace
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var closeBrace = this.lexer.lex(color.position, mode);
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expect(closeBrace, "}");
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this.expect(closeBrace, "}");
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return new ParseResult(
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new ParseNode("color", color.text),
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closeBrace.position);
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} else {
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// It has to have an open brace, so if it doesn't we throw
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throw new ParseError(
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"Parse error: There must be braces around colors");
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"There must be braces around colors",
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this.lexer, pos
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);
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}
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};
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@ -254,7 +264,9 @@ Parser.prototype.parseNucleus = function(pos, mode) {
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group.position);
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} else {
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throw new ParseError(
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"Expected group after '" + nucleus.text + "'");
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"Expected group after '" + nucleus.text + "'",
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this.lexer, nucleus.position
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);
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}
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} else if (nucleus.type === "\\color") {
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// If this is a custom color function, parse its first argument as a
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@ -276,11 +288,15 @@ Parser.prototype.parseNucleus = function(pos, mode) {
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inner.position);
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} else {
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throw new ParseError(
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"Expected second group after '" + nucleus.text + "'");
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"Expected second group after '" + nucleus.text + "'",
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this.lexer, color.position
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);
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}
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} else {
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throw new ParseError(
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"Expected color after '" + nucleus.text + "'");
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"Expected color after '" + nucleus.text + "'",
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this.lexer, nucleus.position
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);
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}
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} else if (mode === "math" && utils.contains(sizeFuncs, nucleus.type)) {
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// If this is a size function, parse its argument and return
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@ -294,7 +310,9 @@ Parser.prototype.parseNucleus = function(pos, mode) {
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group.position);
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} else {
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throw new ParseError(
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"Expected group after '" + nucleus.text + "'");
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"Expected group after '" + nucleus.text + "'",
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this.lexer, nucleus.position
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);
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}
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} else if (mode === "math" && utils.contains(namedFns, nucleus.type)) {
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// If this is a named function, just return it plain
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@ -310,7 +328,9 @@ Parser.prototype.parseNucleus = function(pos, mode) {
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group.position);
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} else {
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throw new ParseError(
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"Expected group after '" + nucleus.text + "'");
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"Expected group after '" + nucleus.text + "'",
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this.lexer, nucleus.position
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);
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}
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} else if (mode === "math" && nucleus.type === "\\text") {
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var group = this.parseGroup(nucleus.position, "text");
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@ -320,7 +340,9 @@ Parser.prototype.parseNucleus = function(pos, mode) {
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group.position);
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} else {
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throw new ParseError(
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"Expected group after '" + nucleus.text + "'");
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"Expected group after '" + nucleus.text + "'",
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this.lexer, nucleus.position
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);
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}
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} else if (mode === "math" && (nucleus.type === "\\dfrac" ||
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nucleus.type === "\\frac" ||
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@ -339,11 +361,15 @@ Parser.prototype.parseNucleus = function(pos, mode) {
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denom.position);
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} else {
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throw new ParseError("Expected denominator after '" +
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nucleus.type + "'");
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nucleus.type + "'",
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this.lexer, numer.position
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);
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}
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} else {
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throw new ParseError("Parse error: Expected numerator after '" +
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nucleus.type + "'");
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throw new ParseError("Expected numerator after '" +
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nucleus.type + "'",
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this.lexer, nucleus.position
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);
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}
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} else if (mode === "math" && nucleus.type === "\\KaTeX") {
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// If this is a KaTeX node, return the special katex result
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@ -440,7 +440,7 @@ var buildGroup = function(group, options, prev) {
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if (options.depth > 1) {
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throw new ParseError(
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"Error: Can't use sizing outside of the root node");
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"Can't use sizing outside of the root node");
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}
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groupNode.height *= multiplier;
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@ -450,7 +450,7 @@ var buildGroup = function(group, options, prev) {
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return groupNode;
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} else {
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throw new ParseError(
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"Lex error: Got group of unknown type: '" + group.type + "'");
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"Got group of unknown type: '" + group.type + "'");
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}
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};
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