# HG changeset patch
# User Matthew Wild <mwild1@gmail.com>
# Date 1264625452 0
# Node ID e190c1643a8ff07539820c0c78a3764dead64ea1
# Parent  8111c8a9e1ad4a72646477283183df62859ef035
mod_latex: New (well, kind of) module for rendering LaTeX in messages and replacing with a rendered embedded image

diff -r 8111c8a9e1ad -r e190c1643a8f mod_latex/mod_latex.lua
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/mod_latex/mod_latex.lua	Wed Jan 27 20:50:52 2010 +0000
@@ -0,0 +1,57 @@
+local st = require "stanza";
+local urlencode = require "net.http".urlencode;
+
+local xmlns_xhtmlim = "http://jabber.org/protocol/xhtml-im";
+local xmlns_xhtml = "http://www.w3.org/1999/xhtml";
+
+local function replace_latex(data)
+	module:log("debug", "Replacing latex...");
+	local origin, stanza = data.origin, data.stanza;
+	local body = stanza:child_with_name("body");
+	if not body then return; end
+	
+	body = body:get_text();
+	if not body:match("%$%$") then
+		return;
+	end
+	
+	local html = st.stanza("html", { xmlns = xmlns_xhtmlim })
+		:tag("body", { xmlns = xmlns_xhtml });
+		
+	local in_latex, last_char;
+	for snippet, up_to in body:gmatch("(.-)%$%$()") do
+		last_char = up_to;
+		if in_latex then
+			-- Render latex and add image, next snippet is text
+			in_latex = nil;
+			html:tag("img", { src = "http://www.mathtran.org/cgi-bin/mathtran?D=2;tex="..urlencode(snippet), alt = snippet }):up();
+		else
+			-- Add text to HTML, next snippet is latex
+			in_latex = true;
+			html:tag("span"):text(snippet):up();
+			
+		end
+	end
+	if last_char < #body then
+		html:tag("span"):text(body:sub(last_char, #body)):up();
+	end
+	
+	for n, tag in ipairs(stanza.tags) do
+		module:log("debug", "Tag: %s|%s", tag.attr.xmlns or "", tag.name or "");
+		if tag.name == "html" and tag.attr.xmlns == xmlns_xhtmlim then
+			stanza.tags[n] = html;
+			for n, child in ipairs(stanza) do
+				if child == tag then
+					stanza[n] = html;
+				end
+			end
+			return;
+		end
+	end
+	
+	stanza[#stanza+1] = html;
+	stanza.tags[#stanza.tags+1] = html;
+end
+
+module:hook("message/bare", replace_latex, 30);
+module:hook("message/full", replace_latex, 30);