Re-land "Check in a simple pure-python based Markdown previewer."

third_party/Python-Markdown/markdown/extensions/tables.py

+"""
+Tables Extension for Python-Markdown
+====================================
+
+Added parsing of tables to Python-Markdown.
+
+See <https://pythonhosted.org/Markdown/extensions/tables.html>
+for documentation.
+
+Original code Copyright 2009 [Waylan Limberg](http://achinghead.com)
+
+All changes Copyright 2008-2014 The Python Markdown Project
+
+License: [BSD](http://www.opensource.org/licenses/bsd-license.php)
+
+"""
+
+from __future__ import absolute_import
+from __future__ import unicode_literals
+from . import Extension
+from ..blockprocessors import BlockProcessor
+from ..util import etree
+
+
+class TableProcessor(BlockProcessor):
+    """ Process Tables. """
+
+    def test(self, parent, block):
+        rows = block.split('\n')
+        return (len(rows) > 1 and '|' in rows[0] and
+                '|' in rows[1] and '-' in rows[1] and
+                rows[1].strip()[0] in ['|', ':', '-'])
+
+    def run(self, parent, blocks):
+        """ Parse a table block and build table. """
+        block = blocks.pop(0).split('\n')
+        header = block[0].strip()
+        seperator = block[1].strip()
+        rows = [] if len(block) < 3 else block[2:]
+        # Get format type (bordered by pipes or not)
+        border = False
+        if header.startswith('|'):
+            border = True
+        # Get alignment of columns
+        align = []
+        for c in self._split_row(seperator, border):
+            if c.startswith(':') and c.endswith(':'):
+                align.append('center')
+            elif c.startswith(':'):
+                align.append('left')
+            elif c.endswith(':'):
+                align.append('right')
+            else:
+                align.append(None)
+        # Build table
+        table = etree.SubElement(parent, 'table')
+        thead = etree.SubElement(table, 'thead')
+        self._build_row(header, thead, align, border)
+        tbody = etree.SubElement(table, 'tbody')
+        for row in rows:
+            self._build_row(row.strip(), tbody, align, border)
+
+    def _build_row(self, row, parent, align, border):
+        """ Given a row of text, build table cells. """
+        tr = etree.SubElement(parent, 'tr')
+        tag = 'td'
+        if parent.tag == 'thead':
+            tag = 'th'
+        cells = self._split_row(row, border)
+        # We use align here rather than cells to ensure every row
+        # contains the same number of columns.
+        for i, a in enumerate(align):
+            c = etree.SubElement(tr, tag)
+            try:
+                c.text = cells[i].strip()
+            except IndexError:  # pragma: no cover
+                c.text = ""
+            if a:
+                c.set('align', a)
+
+    def _split_row(self, row, border):
+        """ split a row of text into list of cells. """
+        if border:
+            if row.startswith('|'):
+                row = row[1:]
+            if row.endswith('|'):
+                row = row[:-1]
+        return row.split('|')
+
+
+class TableExtension(Extension):
+    """ Add tables to Markdown. """
+
+    def extendMarkdown(self, md, md_globals):
+        """ Add an instance of TableProcessor to BlockParser. """
+        md.parser.blockprocessors.add('table',
+                                      TableProcessor(md.parser),
+                                      '<hashheader')
+
+
+def makeExtension(*args, **kwargs):
+    return TableExtension(*args, **kwargs)