My idea is like this:
string render_math(string text)
{
tree parse_tree = parse_and_validate (text);
if (parse_tree != NULL)
{
string new_text = render_tex(parse_tree);
string hash = md5(new_text);
string file_name = file_prefix + hash;
if (file_exists(file_name))
return "<img ... alt=" + htmlattr_escape(text) + ">";
else
if (tex_render(new_text, file_name))
return "<img ... alt=" + htmlattr_escape(text) + ">";
else
return "<b>Warning: couldn't render: " + wiki_escape(text) +
"</b>";
} else {
return text;
}
}
Where:
md5() - obvious
file_prefix - obvious
httmlattr_espace() - obvious
wiki_escape() - obvious
file_exists() - obvious
tex_render() - call external tex rendering program
parse_and_validate() - generated LALR parser which checks if TeX
is safe. If it doesn't understand it, then
it's NOT safe.
render_tex() - render TeX string from tree. Place to add
all extra features, alternative syntaxes etc.
In easiest version just copies first text.
What do you think ?