diff --git a/README.md b/README.md
index 1b36e7b..49dcc91 100644
--- a/README.md
+++ b/README.md
@@ -75,6 +75,17 @@ $$\begin{array}{c}
\end{array}$$
```
+## Syntax
+
+Math parsing in markdown is designed to agree with the conventions set by pandoc:
+
+ Anything between two $ characters will be treated as TeX math. The opening $ must
+ have a non-space character immediately to its right, while the closing $ must
+ have a non-space character immediately to its left, and must not be followed
+ immediately by a digit. Thus, $20,000 and $30,000 won’t parse as math. If for some
+ reason you need to enclose text in literal $ characters, backslash-escape them and
+ they won’t be treated as math delimiters.
+
## Math Syntax Support
KaTeX is based on TeX and LaTeX. Support for both is growing. Here's a list of
diff --git a/index.js b/index.js
index 92c0866..57e8eea 100644
--- a/index.js
+++ b/index.js
@@ -7,167 +7,191 @@ It differs in that it takes (a subset of) LaTeX as input and relies on KaTeX
for rendering output.
*/
+/*jslint node: true */
'use strict';
var katex = require('katex');
-//return if we have valid delimiter, '$', is in the position.
-function isValidDelim(state) {
- var lastChar, secondLastChar, nextChar, pos = state.pos;
+// Test if potential opening or closing delimieter
+// Assumes that there is a "$" at state.src[pos]
+function isValidDelim(state, pos) {
+ var prevChar, nextChar,
+ max = state.posMax,
+ can_open = true,
+ can_close = true;
- if(state.src[pos]!=='$'){
- return false; //the character $ must be in its position.
- }
+ prevChar = pos > 0 ? state.src.charCodeAt(pos - 1) : -1;
+ nextChar = pos + 1 <= max ? state.src.charCodeAt(pos + 1) : -1;
- secondLastChar= pos > 1 ? state.src[pos-2] : ' '
- lastChar = pos > 0 ? state.src[pos-1] : ' '
- nextChar = pos + 1 < state.src.length ? state.src[pos+1] : ' '
+ // Check non-whitespace conditions for opening and closing, and
+ // check that closing delimeter isn't followed by a number
+ if (prevChar === 0x20/* " " */ || prevChar === 0x09/* \t */ ||
+ (nextChar >= 0x30/* "0" */ && nextChar <= 0x39/* "9" */)) {
+ can_close = false;
+ }
+ if (nextChar === 0x20/* " " */ || nextChar === 0x09/* \t */) {
+ can_open = false;
+ }
- if(
- lastChar === '\\' //$ we found was escaped.
- || (lastChar === '$' && secondLastChar !== '\\') // $ we found was after $ but not escaped.
- || nextChar === '$' //$ we found was actually block delimiter $$.
- )
- {
- return false;
- }
-
- return true;
+ return {
+ can_open: can_open,
+ can_close: can_close
+ };
}
-function math_inline(state, silent){
- var start, found = false, token;
- if(silent) { return false; }
+function math_inline(state, silent) {
+ var start, match, token, res, pos, esc_count;
- start = state.pos;
- if(state.src[start] !== '$'){ return false; }
- if(!isValidDelim(state)){
- state.pos += 1;
- state.pending += '$';
- return true;
- }
- state.pos+=1;
+ if (state.src[state.pos] !== "$") { return false; }
- while(state.pos < state.posMax){
- if(isValidDelim(state)){
- found = true;
- break;
+ res = isValidDelim(state, state.pos);
+ if (!res.can_open) {
+ if (!silent) { state.pending += "$"; }
+ state.pos += 1;
+ return true;
}
- state.md.inline.skipToken(state);
- }
- if(!found){
- // Parser failed to find closing delimiter, so it is not a valid math
- state.pos = start;
- return false;
- }
- if (start + 1 === state.pos) {
- // There is nothing between the delimiters -- don't match.
- state.pos = start;
- return false;
- }
+ // First check for and bypass all properly escaped delimieters
+ // This loop will assume that the first leading backtick can not
+ // be the first character in state.src, which is known since
+ // we have found an opening delimieter already.
+ start = state.pos + 1;
+ match = start;
+ while ( (match = state.src.indexOf("$", match)) !== -1) {
+ // Found potential $, look for escapes, pos will point to
+ // first non escape when complete
+ pos = match - 1;
+ while (state.src[pos] === "\\") { pos -= 1; }
- //found the closing delimiter and state.pos is pointing it
- token = state.push('math_inline','math',0);
- token.content = state.src.slice(start+1,state.pos).trim();
- token.markup = '$';
+ // Even number of escapes, potential closing delimiter found
+ if ( ((match - pos) % 2) == 1 ) { break; }
+ match += 1;
+ }
- state.pos += 1;
- return true;
+ // No closing delimter found. Consume $ and continue.
+ if (match === -1) {
+ if (!silent) { state.pending += "$"; }
+ state.pos = start;
+ return true;
+ }
+
+ // Check if we have empty content, ie: $$. Do not parse.
+ if (match - start === 0) {
+ if (!silent) { state.pending += "$$"; }
+ state.pos = start + 1;
+ return true;
+ }
+
+ // Check for valid closing delimiter
+ res = isValidDelim(state, match);
+ if (!res.can_close) {
+ if (!silent) { state.pending += "$"; }
+ state.pos = start;
+ return true;
+ }
+
+ if (!silent) {
+ token = state.push('math_inline', 'math', 0);
+ token.markup = "$";
+ token.content = state.src.slice(start, match);
+ }
+
+ state.pos = match + 1;
+ return true;
}
function math_block(state, start, end, silent){
- var firstLine, lastLine, next, lastPos, found = false, token,
- pos = state.bMarks[start] + state.tShift[start],
- max = state.eMarks[start]
+ var firstLine, lastLine, next, lastPos, found = false, token,
+ pos = state.bMarks[start] + state.tShift[start],
+ max = state.eMarks[start]
- if(pos + 2 > max){ return false; }
- if(state.src.slice(pos,pos+2)!=='$$'){ return false; }
+ if(pos + 2 > max){ return false; }
+ if(state.src.slice(pos,pos+2)!=='$$'){ return false; }
- pos += 2;
- firstLine = state.src.slice(pos,max);
+ pos += 2;
+ firstLine = state.src.slice(pos,max);
- if(silent){ return true; }
- if(firstLine.trim().slice(-2)==='$$'){
- // Single line expression
- firstLine = firstLine.trim().slice(0, -2);
- found = true;
- }
-
- for(next = start; !found; ){
-
- next++;
-
- if(next >= end){ break; }
-
- pos = state.bMarks[next]+state.tShift[next];
- max = state.eMarks[next];
-
- if(pos < max && state.tShift[next] < state.blkIndent){
- // non-empty line with negative indent should stop the list:
- break;
+ if(silent){ return true; }
+ if(firstLine.trim().slice(-2)==='$$'){
+ // Single line expression
+ firstLine = firstLine.trim().slice(0, -2);
+ found = true;
}
- if(state.src.slice(pos,max).trim().slice(-2)==='$$'){
- lastPos = state.src.slice(0,max).lastIndexOf('$$');
- lastLine = state.src.slice(pos,lastPos);
- found = true;
+ for(next = start; !found; ){
+
+ next++;
+
+ if(next >= end){ break; }
+
+ pos = state.bMarks[next]+state.tShift[next];
+ max = state.eMarks[next];
+
+ if(pos < max && state.tShift[next] < state.blkIndent){
+ // non-empty line with negative indent should stop the list:
+ break;
+ }
+
+ if(state.src.slice(pos,max).trim().slice(-2)==='$$'){
+ lastPos = state.src.slice(0,max).lastIndexOf('$$');
+ lastLine = state.src.slice(pos,lastPos);
+ found = true;
+ }
+
}
- }
+ state.line = next + 1;
- state.line = next + 1;
-
- token = state.push('math_block', 'math', 0);
- token.block = true;
- token.content = (firstLine && firstLine.trim() ? firstLine + '\n' : '')
+ token = state.push('math_block', 'math', 0);
+ token.block = true;
+ token.content = (firstLine && firstLine.trim() ? firstLine + '\n' : '')
+ state.getLines(start + 1, next, state.tShift[start], true)
+ (lastLine && lastLine.trim() ? lastLine : '');
- token.map = [ start, state.line ];
- token.markup = '$$';
- return true;
+ token.map = [ start, state.line ];
+ token.markup = '$$';
+ return true;
}
module.exports = function math_plugin(md, options) {
- // Default options
+ // Default options
- options = options || {};
+ options = options || {};
- // set KaTeX as the renderer for markdown-it-simplemath
- var katexInline = function(latex){
- options.displayMode = false;
- try{
- return katex.renderToString(latex, options);
+ // set KaTeX as the renderer for markdown-it-simplemath
+ var katexInline = function(latex){
+ options.displayMode = false;
+ try{
+ return katex.renderToString(latex, options);
+ }
+ catch(error){
+ if(options.throwOnError){ console.log(error); }
+ return latex;
+ }
+ };
+
+ var inlineRenderer = function(tokens, idx){
+ return katexInline(tokens[idx].content);
+ };
+
+ var katexBlock = function(latex){
+ options.displayMode = true;
+ try{
+ return "" + katex.renderToString(latex, options) + "
";
+ }
+ catch(error){
+ if(options.throwOnError){ console.log(error); }
+ return latex;
+ }
}
- catch(error){
- if(options.throwOnError){ console.log(error); }
- return latex;
+
+ var blockRenderer = function(tokens, idx){
+ return katexBlock(tokens[idx].content) + '\n';
}
- };
- var inlineRenderer = function(tokens, idx){
- return katexInline(tokens[idx].content);
- };
-
- var katexBlock = function(latex){
- options.displayMode = true;
- try{
- return "" + katex.renderToString(latex, options) + "
";
- }
- catch(error){
- if(options.throwOnError){ console.log(error); }
- return latex;
- }
- }
-
- var blockRenderer = function(tokens, idx){
- return katexBlock(tokens[idx].content) + '\n';
- }
-
- md.inline.ruler.before('escape', 'math_inline', math_inline);
- md.block.ruler.after('blockquote', 'math_block', math_block, {
- alt: [ 'paragraph', 'reference', 'blockquote', 'list' ]
- });
- md.renderer.rules.math_inline = inlineRenderer;
- md.renderer.rules.math_block = blockRenderer;
+ md.inline.ruler.after('escape', 'math_inline', math_inline);
+ md.block.ruler.after('blockquote', 'math_block', math_block, {
+ alt: [ 'paragraph', 'reference', 'blockquote', 'list' ]
+ });
+ md.renderer.rules.math_inline = inlineRenderer;
+ md.renderer.rules.math_block = blockRenderer;
};
diff --git a/package.json b/package.json
index 60dd09e..c093e15 100644
--- a/package.json
+++ b/package.json
@@ -22,7 +22,7 @@
"author": "waylonflinn@gmail.com",
"license": "MIT",
"dependencies": {
- "katex": "^0.5.1"
+ "katex": "^0.6.0"
},
"devDependencies": {
"markdown-it": "^6.0.0",
diff --git a/test/fixtures/default.txt b/test/fixtures/default.txt
index 6c6e482..bf9dc4e 100644
--- a/test/fixtures/default.txt
+++ b/test/fixtures/default.txt
@@ -35,20 +35,13 @@ aaa $$ bbb
aaa $$ bbb
.
-Shouldn't render USD
+Should require a closing delimiter
.
aaa $5.99 bbb
.
aaa $5.99 bbb
.
-Shouldn't render trailing delimiter
-.
-aaa 5.99$ bbb
-.
-aaa 5.99$ bbb
-.
-
Paragraph break in inline math is not allowed
.
foo $1+1
@@ -59,14 +52,7 @@ foo $1+1
= 2$ bar
.
-Neither is an end of document
-.
-foo $1+1 = 2
-.
-foo $1+1 = 2
-.
-
-Inline math with apparent markup
+Inline math with apparent markup should not be processed
.
foo $1 *i* 1$ bar
.
@@ -193,3 +179,45 @@ $$
1
$$
.
+
+Numbers can not follow closing inline math
+.
+Thus, $20,000 and USD$30,000 won't parse as math.
+.
+Thus, $20,000 and USD$30,000 won't parse as math.
+.
+
+Require non whitespace to right of opening inline math
+.
+For some Europeans, it is 2$ for a can of soda, not 1$.
+.
+For some Europeans, it is 2$ for a can of soda, not 1$.
+.
+
+Require non whitespace to left of closing inline math.
+.
+I will give you $20 today, if you give me more $ tomorrow.
+.
+I will give you $20 today, if you give me more $ tomorrow.
+.
+
+Inline blockmath is not (currently) registered.
+.
+It's well know that $$1 + 1 = 3$$ for sufficiently large 1.
+.
+It's well know that $$1 + 1 = 3$$ for sufficiently large 1.
+.
+
+Escaped delimiters in math mode
+.
+Money adds: $\$X + \$Y = \$Z$.
+.
+Money adds: $X+$Y=$Z.
+.
+
+Multiple escaped delimiters in math module
+.
+Weird-o: $\displaystyle{\begin{pmatrix} \$ & 1\\\$ \end{pmatrix}}$.
+.
+Weird-o: ($$1).
+.