1"""
2Table of Contents Extension for Python-Markdown
3* * *
4
5(c) 2008 [Jack Miller](http://codezen.org)
6
7Dependencies:
8* [Markdown 2.0+](http://www.freewisdom.org/projects/python-markdown/)
9
10"""
11import markdown
12from markdown import etree
13import re
14
15class TocTreeprocessor(markdown.treeprocessors.Treeprocessor):
16    # Iterator wrapper to get parent and child all at once
17    def iterparent(self, root):
18        for parent in root.getiterator():
19            for child in parent:
20                yield parent, child
21
22    def run(self, doc):
23        div = etree.Element("div")
24        div.attrib["class"] = "toc"
25        last_li = None
26
27        # Add title to the div
28        if self.config["title"][0]:
29            header = etree.SubElement(div, "span")
30            header.attrib["class"] = "toctitle"
31            header.text = self.config["title"][0]
32
33        level = 0
34        list_stack=[div]
35        header_rgx = re.compile("[Hh][123456]")
36
37        # Get a list of id attributes
38        used_ids = []
39        for c in doc.getiterator():
40            if "id" in c.attrib:
41                used_ids.append(c.attrib["id"])
42
43        for (p, c) in self.iterparent(doc):
44            if not c.text:
45                continue
46
47            # To keep the output from screwing up the
48            # validation by putting a <div> inside of a <p>
49            # we actually replace the <p> in its entirety.
50            # We do not allow the marker inside a header as that
51            # would causes an enless loop of placing a new TOC
52            # inside previously generated TOC.
53
54            if c.text.find(self.config["marker"][0]) > -1 and not header_rgx.match(c.tag):
55                for i in range(len(p)):
56                    if p[i] == c:
57                        p[i] = div
58                        break
59
60            if header_rgx.match(c.tag):
61                tag_level = int(c.tag[-1])
62
63                while tag_level < level:
64                    list_stack.pop()
65                    level -= 1
66
67                if tag_level > level:
68                    newlist = etree.Element("ul")
69                    if last_li:
70                        last_li.append(newlist)
71                    else:
72                        list_stack[-1].append(newlist)
73                    list_stack.append(newlist)
74                    level += 1
75
76                # Do not override pre-existing ids
77                if not "id" in c.attrib:
78                    id = self.config["slugify"][0](c.text)
79                    if id in used_ids:
80                        ctr = 1
81                        while "%s_%d" % (id, ctr) in used_ids:
82                            ctr += 1
83                        id = "%s_%d" % (id, ctr)
84                    used_ids.append(id)
85                    c.attrib["id"] = id
86                else:
87                    id = c.attrib["id"]
88
89                # List item link, to be inserted into the toc div
90                last_li = etree.Element("li")
91                link = etree.SubElement(last_li, "a")
92                link.text = c.text
93                link.attrib["href"] = '#' + id
94
95                if int(self.config["anchorlink"][0]):
96                    anchor = etree.SubElement(c, "a")
97                    anchor.text = c.text
98                    anchor.attrib["href"] = "#" + id
99                    anchor.attrib["class"] = "toclink"
100                    c.text = ""
101
102                list_stack[-1].append(last_li)
103
104class TocExtension(markdown.Extension):
105    def __init__(self, configs):
106        self.config = { "marker" : ["[TOC]",
107                            "Text to find and replace with Table of Contents -"
108                            "Defaults to \"[TOC]\""],
109                        "slugify" : [self.slugify,
110                            "Function to generate anchors based on header text-"
111                            "Defaults to a built in slugify function."],
112                        "title" : [None,
113                            "Title to insert into TOC <div> - "
114                            "Defaults to None"],
115                        "anchorlink" : [0,
116                            "1 if header should be a self link"
117                            "Defaults to 0"]}
118
119        for key, value in configs:
120            self.setConfig(key, value)
121
122    # This is exactly the same as Django's slugify
123    def slugify(self, value):
124        """ Slugify a string, to make it URL friendly. """
125        import unicodedata
126        value = unicodedata.normalize('NFKD', value).encode('ascii', 'ignore')
127        value = unicode(re.sub('[^\w\s-]', '', value).strip().lower())
128        return re.sub('[-\s]+','-',value)
129
130    def extendMarkdown(self, md, md_globals):
131        tocext = TocTreeprocessor(md)
132        tocext.config = self.config
133        md.treeprocessors.add("toc", tocext, "_begin")
134
135def makeExtension(configs={}):
136    return TocExtension(configs=configs)
137