From 8e0239035357e31395cec7dafc2ee64c1f115714 Mon Sep 17 00:00:00 2001
From: Santiago Pelufo <santiagopelufo@gmail.com>
Date: Thu, 24 Dec 2015 13:45:45 -0300
Subject: [PATCH] Revert katex plugin to using `$$`. Use multiline for display
 mode.

---
 editions/katexdemo/tiddlers/HelloThere.tid | 26 ++++++++++++++++------
 plugins/tiddlywiki/katex/latex-parser.js   |  6 ++---
 plugins/tiddlywiki/katex/usage.tid         |  2 +-
 3 files changed, 23 insertions(+), 11 deletions(-)

diff --git a/editions/katexdemo/tiddlers/HelloThere.tid b/editions/katexdemo/tiddlers/HelloThere.tid
index e0a32b20a..0d058a371 100644
--- a/editions/katexdemo/tiddlers/HelloThere.tid
+++ b/editions/katexdemo/tiddlers/HelloThere.tid
@@ -22,30 +22,42 @@ These examples are taken from http://khan.github.io/KaTeX/
 
 !! Example 1
 
-To render in display mode use `$$$`:
+If the text between `$$` contains newlines it will rendered in display mode:
 
 ```
-$$$ f(x) = \int_{-\infty}^\infty\hat f(\xi)\,e^{2 \pi i \xi x}\,d\xi $$$
+$$
+f(x) = \int_{-\infty}^\infty\hat f(\xi)\,e^{2 \pi i \xi x}\,d\xi
+$$
 ```
 
-$$$ f(x) = \int_{-\infty}^\infty\hat f(\xi)\,e^{2 \pi i \xi x}\,d\xi $$$
+$$
+f(x) = \int_{-\infty}^\infty\hat f(\xi)\,e^{2 \pi i \xi x}\,d\xi
+$$
 
 !! Example 2
 
 ```
-$$$ \frac{1}{\Bigl(\sqrt{\phi \sqrt{5}}-\phi\Bigr) e^{\frac25 \pi}} = 1+\frac{e^{-2\pi}} {1+\frac{e^{-4\pi}} {1+\frac{e^{-6\pi}} {1+\frac{e^{-8\pi}} {1+\cdots} } } } $$$
+$$
+\frac{1}{\Bigl(\sqrt{\phi \sqrt{5}}-\phi\Bigr) e^{\frac25 \pi}} = 1+\frac{e^{-2\pi}} {1+\frac{e^{-4\pi}} {1+\frac{e^{-6\pi}} {1+\frac{e^{-8\pi}} {1+\cdots} } } }
+$$
 ```
 
-$$$ \frac{1}{\Bigl(\sqrt{\phi \sqrt{5}}-\phi\Bigr) e^{\frac25 \pi}} = 1+\frac{e^{-2\pi}} {1+\frac{e^{-4\pi}} {1+\frac{e^{-6\pi}} {1+\frac{e^{-8\pi}} {1+\cdots} } } } $$$
+$$
+\frac{1}{\Bigl(\sqrt{\phi \sqrt{5}}-\phi\Bigr) e^{\frac25 \pi}} = 1+\frac{e^{-2\pi}} {1+\frac{e^{-4\pi}} {1+\frac{e^{-6\pi}} {1+\frac{e^{-8\pi}} {1+\cdots} } } }
+$$
 
 
 !! Example 3
 
 ```
-$$$ 1 +  \frac{q^2}{(1-q)}+\frac{q^6}{(1-q)(1-q^2)}+\cdots = \prod_{j=0}^{\infty}\frac{1}{(1-q^{5j+2})(1-q^{5j+3})}, \quad\quad \text{for }\lvert q\rvert<1. $$$
+$$
+1 +  \frac{q^2}{(1-q)}+\frac{q^6}{(1-q)(1-q^2)}+\cdots = \prod_{j=0}^{\infty}\frac{1}{(1-q^{5j+2})(1-q^{5j+3})}, \quad\quad \text{for }\lvert q\rvert<1.
+$$
 ```
 
-$$$ 1 +  \frac{q^2}{(1-q)}+\frac{q^6}{(1-q)(1-q^2)}+\cdots = \prod_{j=0}^{\infty}\frac{1}{(1-q^{5j+2})(1-q^{5j+3})}, \quad\quad \text{for }\lvert q\rvert<1. $$$
+$$
+1 +  \frac{q^2}{(1-q)}+\frac{q^6}{(1-q)(1-q^2)}+\cdots = \prod_{j=0}^{\infty}\frac{1}{(1-q^{5j+2})(1-q^{5j+3})}, \quad\quad \text{for }\lvert q\rvert<1.
+$$
 
 !! Widget Example
 
diff --git a/plugins/tiddlywiki/katex/latex-parser.js b/plugins/tiddlywiki/katex/latex-parser.js
index 0aacfd488..6b72c7f51 100644
--- a/plugins/tiddlywiki/katex/latex-parser.js
+++ b/plugins/tiddlywiki/katex/latex-parser.js
@@ -29,13 +29,13 @@ exports.types = {inline: true};
 exports.init = function(parser) {
 	this.parser = parser;
 	// Regexp to match
-	this.matchRegExp = /\$\$\$?(?!\$)/mg;
+	this.matchRegExp = /\$\$(?!\$)/mg;
 };
 
 exports.parse = function() {
 	// Move past the match
 	this.parser.pos = this.matchRegExp.lastIndex;
-	var reEnd = /\$\$\$?/mg;
+	var reEnd = /\$\$/mg;
 	// Look for the end marker
 	reEnd.lastIndex = this.parser.pos;
 	var match = reEnd.exec(this.parser.source),
@@ -44,7 +44,7 @@ exports.parse = function() {
 	// Process the text
 	if(match) {
 		text = this.parser.source.substring(this.parser.pos,match.index);
-		displayMode = match.indexOf('$$$') != -1;
+		displayMode = text.indexOf('\n') != -1;
 		this.parser.pos = match.index + match[0].length;
 	} else {
 		text = this.parser.source.substr(this.parser.pos);
diff --git a/plugins/tiddlywiki/katex/usage.tid b/plugins/tiddlywiki/katex/usage.tid
index bb9101092..8e7e53bb9 100644
--- a/plugins/tiddlywiki/katex/usage.tid
+++ b/plugins/tiddlywiki/katex/usage.tid
@@ -6,7 +6,7 @@ The usual way to include ~LaTeX is to use `$$`. For example:
 $$\displaystyle f(x) = \int_{-\infty}^\infty\hat f(\xi)\,e^{2 \pi i \xi x}\,d\xi$$
 ```
 
-To make math render in display mode, use `$$$` instead of `$$`.
+Single line equations will render in inline mode. If there are newlines between the `$$` delimiters, the equations will be rendered in display mode.
 
 The underlying widget can also be used directly, giving more flexibility: