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# minirst.py - minimal reStructuredText parser
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#
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# Copyright 2009 Matt Mackall <mpm@selenic.com> and others
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#
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# This software may be used and distributed according to the terms of the
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# GNU General Public License version 2, incorporated herein by reference.
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"""simplified reStructuredText parser.
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This parser knows just enough about reStructuredText to parse the
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Mercurial docstrings.
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It cheats in a major way: nested blocks are not really nested. They
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are just indented blocks that look like they are nested. This relies
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on the user to keep the right indentation for the blocks.
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It only supports a small subset of reStructuredText:
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- paragraphs
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- definition lists (must use ' ' to indent definitions)
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- lists (items must start with '-')
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- field lists (colons cannot be escaped)
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- literal blocks
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- option lists (supports only long options without arguments)
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- inline markup is not recognized at all.
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"""
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import re, sys, textwrap
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def findblocks(text):
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"""Find continuous blocks of lines in text.
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Returns a list of dictionaries representing the blocks. Each block
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has an 'indent' field and a 'lines' field.
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"""
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blocks = [[]]
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lines = text.splitlines()
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for line in lines:
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if line.strip():
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blocks[-1].append(line)
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elif blocks[-1]:
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blocks.append([])
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if not blocks[-1]:
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del blocks[-1]
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for i, block in enumerate(blocks):
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indent = min((len(l) - len(l.lstrip())) for l in block)
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blocks[i] = dict(indent=indent, lines=[l[indent:] for l in block])
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return blocks
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def findliteralblocks(blocks):
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"""Finds literal blocks and adds a 'type' field to the blocks.
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Literal blocks are given the type 'literal', all other blocks are
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given type the 'paragraph'.
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"""
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i = 0
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while i < len(blocks):
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# Searching for a block that looks like this:
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#
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# +------------------------------+
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# | paragraph |
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# | (ends with "::") |
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# +------------------------------+
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# +---------------------------+
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# | indented literal block |
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# +---------------------------+
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blocks[i]['type'] = 'paragraph'
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if blocks[i]['lines'][-1].endswith('::') and i+1 < len(blocks):
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indent = blocks[i]['indent']
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adjustment = blocks[i+1]['indent'] - indent
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if blocks[i]['lines'] == ['::']:
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# Expanded form: remove block
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del blocks[i]
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i -= 1
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elif blocks[i]['lines'][-1].endswith(' ::'):
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# Partially minimized form: remove space and both
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# colons.
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blocks[i]['lines'][-1] = blocks[i]['lines'][-1][:-3]
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else:
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# Fully minimized form: remove just one colon.
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blocks[i]['lines'][-1] = blocks[i]['lines'][-1][:-1]
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# List items are formatted with a hanging indent. We must
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# correct for this here while we still have the original
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# information on the indentation of the subsequent literal
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# blocks available.
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if blocks[i]['lines'][0].startswith('- '):
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indent += 2
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adjustment -= 2
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# Mark the following indented blocks.
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while i+1 < len(blocks) and blocks[i+1]['indent'] > indent:
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blocks[i+1]['type'] = 'literal'
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blocks[i+1]['indent'] -= adjustment
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i += 1
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i += 1
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return blocks
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def findsections(blocks):
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"""Finds sections.
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The blocks must have a 'type' field, i.e., they should have been
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run through findliteralblocks first.
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"""
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for block in blocks:
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# Searching for a block that looks like this:
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#
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# +------------------------------+
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# | Section title |
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# | ------------- |
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# +------------------------------+
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if (block['type'] == 'paragraph' and
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len(block['lines']) == 2 and
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block['lines'][1] == '-' * len(block['lines'][0])):
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block['type'] = 'section'
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return blocks
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def findbulletlists(blocks):
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"""Finds bullet lists.
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The blocks must have a 'type' field, i.e., they should have been
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run through findliteralblocks first.
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"""
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i = 0
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while i < len(blocks):
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# Searching for a paragraph that looks like this:
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#
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# +------+-----------------------+
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# | "- " | list item |
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# +------| (body elements)+ |
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# +-----------------------+
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if (blocks[i]['type'] == 'paragraph' and
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blocks[i]['lines'][0].startswith('- ')):
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items = []
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for line in blocks[i]['lines']:
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if line.startswith('- '):
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items.append(dict(type='bullet', lines=[],
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indent=blocks[i]['indent']))
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line = line[2:]
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items[-1]['lines'].append(line)
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blocks[i:i+1] = items
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i += len(items) - 1
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i += 1
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return blocks
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_optionre = re.compile(r'^(--[a-z-]+)((?:[ =][a-zA-Z][\w-]*)? +)(.*)$')
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def findoptionlists(blocks):
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"""Finds option lists.
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The blocks must have a 'type' field, i.e., they should have been
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run through findliteralblocks first.
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"""
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i = 0
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while i < len(blocks):
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# Searching for a paragraph that looks like this:
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#
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# +----------------------------+-------------+
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# | "--" option " " | description |
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# +-------+--------------------+ |
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# | (body elements)+ |
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# +----------------------------------+
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if (blocks[i]['type'] == 'paragraph' and
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_optionre.match(blocks[i]['lines'][0])):
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options = []
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for line in blocks[i]['lines']:
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m = _optionre.match(line)
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if m:
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option, arg, rest = m.groups()
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width = len(option) + len(arg)
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options.append(dict(type='option', lines=[],
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indent=blocks[i]['indent'],
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width=width))
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options[-1]['lines'].append(line)
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blocks[i:i+1] = options
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i += len(options) - 1
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i += 1
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return blocks
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_fieldre = re.compile(r':(?![: ])([^:]*)(?<! ):( +)(.*)')
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def findfieldlists(blocks):
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"""Finds fields lists.
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The blocks must have a 'type' field, i.e., they should have been
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run through findliteralblocks first.
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"""
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i = 0
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while i < len(blocks):
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# Searching for a paragraph that looks like this:
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#
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#
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# +--------------------+----------------------+
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# | ":" field name ":" | field body |
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# +-------+------------+ |
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# | (body elements)+ |
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# +-----------------------------------+
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if (blocks[i]['type'] == 'paragraph' and
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_fieldre.match(blocks[i]['lines'][0])):
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indent = blocks[i]['indent']
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fields = []
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for line in blocks[i]['lines']:
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m = _fieldre.match(line)
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if m:
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key, spaces, rest = m.groups()
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width = 2 + len(key) + len(spaces)
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fields.append(dict(type='field', lines=[],
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indent=indent, width=width))
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# Turn ":foo: bar" into "foo bar".
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line = '%s %s%s' % (key, spaces, rest)
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fields[-1]['lines'].append(line)
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blocks[i:i+1] = fields
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i += len(fields) - 1
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i += 1
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return blocks
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def finddefinitionlists(blocks):
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"""Finds definition lists.
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The blocks must have a 'type' field, i.e., they should have been
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run through findliteralblocks first.
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"""
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i = 0
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while i < len(blocks):
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# Searching for a paragraph that looks like this:
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#
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# +----------------------------+
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# | term |
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# +--+-------------------------+--+
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# | definition |
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# | (body elements)+ |
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# +----------------------------+
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if (blocks[i]['type'] == 'paragraph' and
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len(blocks[i]['lines']) > 1 and
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not blocks[i]['lines'][0].startswith(' ') and
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blocks[i]['lines'][1].startswith(' ')):
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definitions = []
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for line in blocks[i]['lines']:
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if not line.startswith(' '):
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definitions.append(dict(type='definition', lines=[],
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indent=blocks[i]['indent']))
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definitions[-1]['lines'].append(line)
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definitions[-1]['hang'] = len(line) - len(line.lstrip())
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blocks[i:i+1] = definitions
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i += len(definitions) - 1
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i += 1
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return blocks
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def addmargins(blocks):
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"""Adds empty blocks for vertical spacing.
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This groups bullets, options, and definitions together with no vertical
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space between them, and adds an empty block between all other blocks.
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"""
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i = 1
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while i < len(blocks):
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if (blocks[i]['type'] == blocks[i-1]['type'] and
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blocks[i]['type'] in ('bullet', 'option', 'field', 'definition')):
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i += 1
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else:
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blocks.insert(i, dict(lines=[''], indent=0, type='margin'))
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i += 2
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return blocks
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def formatblock(block, width):
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"""Format a block according to width."""
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indent = ' ' * block['indent']
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if block['type'] == 'margin':
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return ''
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elif block['type'] == 'literal':
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indent += ' '
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return indent + ('\n' + indent).join(block['lines'])
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elif block['type'] == 'section':
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return indent + ('\n' + indent).join(block['lines'])
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elif block['type'] == 'definition':
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term = indent + block['lines'][0]
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defindent = indent + block['hang'] * ' '
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text = ' '.join(map(str.strip, block['lines'][1:]))
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return "%s\n%s" % (term, textwrap.fill(text, width=width,
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initial_indent=defindent,
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subsequent_indent=defindent))
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else:
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initindent = subindent = indent
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text = ' '.join(map(str.strip, block['lines']))
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if block['type'] == 'bullet':
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initindent = indent + '- '
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subindent = indent + ' '
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elif block['type'] in ('option', 'field'):
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subindent = indent + block['width'] * ' '
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return textwrap.fill(text, width=width,
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initial_indent=initindent,
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subsequent_indent=subindent)
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def format(text, width):
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"""Parse and format the text according to width."""
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blocks = findblocks(text)
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blocks = findliteralblocks(blocks)
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blocks = findsections(blocks)
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blocks = findbulletlists(blocks)
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blocks = findoptionlists(blocks)
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blocks = findfieldlists(blocks)
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blocks = finddefinitionlists(blocks)
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blocks = addmargins(blocks)
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return '\n'.join(formatblock(b, width) for b in blocks)
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if __name__ == "__main__":
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from pprint import pprint
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def debug(func, blocks):
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blocks = func(blocks)
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print "*** after %s:" % func.__name__
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pprint(blocks)
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print
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return blocks
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text = open(sys.argv[1]).read()
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blocks = debug(findblocks, text)
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blocks = debug(findliteralblocks, blocks)
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blocks = debug(findsections, blocks)
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blocks = debug(findbulletlists, blocks)
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blocks = debug(findoptionlists, blocks)
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blocks = debug(findfieldlists, blocks)
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blocks = debug(finddefinitionlists, blocks)
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blocks = debug(addmargins, blocks)
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print '\n'.join(formatblock(b, 30) for b in blocks)
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