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Syntax highlighting for Django using Pygments

January 15th, 2010

The wonderful django-mingus includes a few separate syntax highlighters, including one from django-sugar. However, the pygmentize template filter only works on <code> blocks and tries to guess the language.

A better syntax would be to include the language in the class of the code block, like so:

<code class="python"> 
    import this 
    print [r for r in range(0,10,2)] 
</code>

You can use this template filter, which is adapted from the Pygments Rendering Template Filter at Django Snippets.

import re 
import pygments 
from django import template 
from pygments import lexers 
from pygments import formatters 
 
register = template.Library() 
regex = re.compile(r'<code(.*?)>(.*?)</code>', re.DOTALL) 
 
@register.filter(name='pygmentize') 
def pygmentize(value): 
    last_end = 0 
    to_return = '' 
    found = 0 
    for match_obj in regex.finditer(value): 
        code_class = match_obj.group(1) 
        code_string = match_obj.group(2) 
        if code_class.find('class'): 
            language = re.split(r'"|\'', code_class)[1] 
            lexer = lexers.get_lexer_by_name(language) 
        else: 
            try: 
                lexer = lexers.guess_lexer(str(code_string)) 
            except ValueError: 
                lexer = lexers.PythonLexer() 
        pygmented_string = pygments.highlight(code_string, lexer, formatters.HtmlFormatter()) 
        to_return = to_return + value[last_end:match_obj.start(0)] + pygmented_string 
        last_end = match_obj.end(2) 
        found = found + 1 
    to_return = to_return + value[last_end:] 
    return to_return

This is a template filter, which can be applied like so:

You can read more about custom tempalte filters at the Django Project: Writing Custom Template Filters.

Other writing