Sublime autocomplete plugin for Markdown reference links

markdown_reference_completions.py

# -*- coding: UTF-8 -*-
import sublime, sublime_plugin
import re


# Utility function for shortening text.
# From: http://www.leancrew.com/all-this/2012/08/more-markdown-reference-links-in-bbedit/
def shorten(str, n):
    'Truncate str to no more than n chars'
    return str if len(str) <= n else str[:n-1] + u'…'


# Provide completions that match just after typing an opening square bracket
class MarkdownReferenceCompletions(sublime_plugin.EventListener):
    def on_query_completions(self, view, prefix, locations):
        # Only trigger within Markdown reference-style link
        if not view.match_selector(locations[0],
                "text.html.markdown meta.link.reference constant.other.reference.link.markdown, "
                "text.html.markdown meta.link.reference punctuation.definition.constant.end.markdown"):
            return []

        pt = locations[0] - len(prefix)
        ch = view.substr(sublime.Region(pt - 2, pt))
        # Make sure we're inside the reference name portion
        if ch != '][':
            return []

        reflinks = view.find_all(r'^\[([^^\]]+)\]:[ \t]+(https?://)?(.+)$')

        refs = []
        for r in reflinks:
            m = re.match(r'^\[([^^\]]+)\]:[ \t]+(https?://)?(.+)$', view.substr(r))
            if m:
                refs.append((m.group(1) + '\t' + shorten(m.group(3), 30 - len(m.group(1))), m.group(1)))

        return (refs,
            sublime.INHIBIT_WORD_COMPLETIONS | sublime.INHIBIT_EXPLICIT_COMPLETIONS)