ref: d39d1a5303541539f61488317b220c1eb724d7d3
dir: /sys/src/cmd/hg/mercurial/minirst.py/
# minirst.py - minimal reStructuredText parser
#
# Copyright 2009 Matt Mackall <mpm@selenic.com> and others
#
# This software may be used and distributed according to the terms of the
# GNU General Public License version 2, incorporated herein by reference.
"""simplified reStructuredText parser.
This parser knows just enough about reStructuredText to parse the
Mercurial docstrings.
It cheats in a major way: nested blocks are not really nested. They
are just indented blocks that look like they are nested. This relies
on the user to keep the right indentation for the blocks.
It only supports a small subset of reStructuredText:
- paragraphs
- definition lists (must use ' ' to indent definitions)
- lists (items must start with '-')
- field lists (colons cannot be escaped)
- literal blocks
- option lists (supports only long options without arguments)
- inline markup is not recognized at all.
"""
import re, sys, textwrap
def findblocks(text):
"""Find continuous blocks of lines in text.
Returns a list of dictionaries representing the blocks. Each block
has an 'indent' field and a 'lines' field.
"""
blocks = [[]]
lines = text.splitlines()
for line in lines:
if line.strip():
blocks[-1].append(line)
elif blocks[-1]:
blocks.append([])
if not blocks[-1]:
del blocks[-1]
for i, block in enumerate(blocks):
indent = min((len(l) - len(l.lstrip())) for l in block)
blocks[i] = dict(indent=indent, lines=[l[indent:] for l in block])
return blocks
def findliteralblocks(blocks):
"""Finds literal blocks and adds a 'type' field to the blocks.
Literal blocks are given the type 'literal', all other blocks are
given type the 'paragraph'.
"""
i = 0
while i < len(blocks):
# Searching for a block that looks like this:
#
# +------------------------------+
# | paragraph |
# | (ends with "::") |
# +------------------------------+
# +---------------------------+
# | indented literal block |
# +---------------------------+
blocks[i]['type'] = 'paragraph'
if blocks[i]['lines'][-1].endswith('::') and i+1 < len(blocks):
indent = blocks[i]['indent']
adjustment = blocks[i+1]['indent'] - indent
if blocks[i]['lines'] == ['::']:
# Expanded form: remove block
del blocks[i]
i -= 1
elif blocks[i]['lines'][-1].endswith(' ::'):
# Partially minimized form: remove space and both
# colons.
blocks[i]['lines'][-1] = blocks[i]['lines'][-1][:-3]
else:
# Fully minimized form: remove just one colon.
blocks[i]['lines'][-1] = blocks[i]['lines'][-1][:-1]
# List items are formatted with a hanging indent. We must
# correct for this here while we still have the original
# information on the indentation of the subsequent literal
# blocks available.
if blocks[i]['lines'][0].startswith('- '):
indent += 2
adjustment -= 2
# Mark the following indented blocks.
while i+1 < len(blocks) and blocks[i+1]['indent'] > indent:
blocks[i+1]['type'] = 'literal'
blocks[i+1]['indent'] -= adjustment
i += 1
i += 1
return blocks
def findsections(blocks):
"""Finds sections.
The blocks must have a 'type' field, i.e., they should have been
run through findliteralblocks first.
"""
for block in blocks:
# Searching for a block that looks like this:
#
# +------------------------------+
# | Section title |
# | ------------- |
# +------------------------------+
if (block['type'] == 'paragraph' and
len(block['lines']) == 2 and
block['lines'][1] == '-' * len(block['lines'][0])):
block['type'] = 'section'
return blocks
def findbulletlists(blocks):
"""Finds bullet lists.
The blocks must have a 'type' field, i.e., they should have been
run through findliteralblocks first.
"""
i = 0
while i < len(blocks):
# Searching for a paragraph that looks like this:
#
# +------+-----------------------+
# | "- " | list item |
# +------| (body elements)+ |
# +-----------------------+
if (blocks[i]['type'] == 'paragraph' and
blocks[i]['lines'][0].startswith('- ')):
items = []
for line in blocks[i]['lines']:
if line.startswith('- '):
items.append(dict(type='bullet', lines=[],
indent=blocks[i]['indent']))
line = line[2:]
items[-1]['lines'].append(line)
blocks[i:i+1] = items
i += len(items) - 1
i += 1
return blocks
_optionre = re.compile(r'^(--[a-z-]+)((?:[ =][a-zA-Z][\w-]*)? +)(.*)$')
def findoptionlists(blocks):
"""Finds option lists.
The blocks must have a 'type' field, i.e., they should have been
run through findliteralblocks first.
"""
i = 0
while i < len(blocks):
# Searching for a paragraph that looks like this:
#
# +----------------------------+-------------+
# | "--" option " " | description |
# +-------+--------------------+ |
# | (body elements)+ |
# +----------------------------------+
if (blocks[i]['type'] == 'paragraph' and
_optionre.match(blocks[i]['lines'][0])):
options = []
for line in blocks[i]['lines']:
m = _optionre.match(line)
if m:
option, arg, rest = m.groups()
width = len(option) + len(arg)
options.append(dict(type='option', lines=[],
indent=blocks[i]['indent'],
width=width))
options[-1]['lines'].append(line)
blocks[i:i+1] = options
i += len(options) - 1
i += 1
return blocks
_fieldre = re.compile(r':(?![: ])([^:]*)(?<! ):( +)(.*)')
def findfieldlists(blocks):
"""Finds fields lists.
The blocks must have a 'type' field, i.e., they should have been
run through findliteralblocks first.
"""
i = 0
while i < len(blocks):
# Searching for a paragraph that looks like this:
#
#
# +--------------------+----------------------+
# | ":" field name ":" | field body |
# +-------+------------+ |
# | (body elements)+ |
# +-----------------------------------+
if (blocks[i]['type'] == 'paragraph' and
_fieldre.match(blocks[i]['lines'][0])):
indent = blocks[i]['indent']
fields = []
for line in blocks[i]['lines']:
m = _fieldre.match(line)
if m:
key, spaces, rest = m.groups()
width = 2 + len(key) + len(spaces)
fields.append(dict(type='field', lines=[],
indent=indent, width=width))
# Turn ":foo: bar" into "foo bar".
line = '%s %s%s' % (key, spaces, rest)
fields[-1]['lines'].append(line)
blocks[i:i+1] = fields
i += len(fields) - 1
i += 1
return blocks
def finddefinitionlists(blocks):
"""Finds definition lists.
The blocks must have a 'type' field, i.e., they should have been
run through findliteralblocks first.
"""
i = 0
while i < len(blocks):
# Searching for a paragraph that looks like this:
#
# +----------------------------+
# | term |
# +--+-------------------------+--+
# | definition |
# | (body elements)+ |
# +----------------------------+
if (blocks[i]['type'] == 'paragraph' and
len(blocks[i]['lines']) > 1 and
not blocks[i]['lines'][0].startswith(' ') and
blocks[i]['lines'][1].startswith(' ')):
definitions = []
for line in blocks[i]['lines']:
if not line.startswith(' '):
definitions.append(dict(type='definition', lines=[],
indent=blocks[i]['indent']))
definitions[-1]['lines'].append(line)
definitions[-1]['hang'] = len(line) - len(line.lstrip())
blocks[i:i+1] = definitions
i += len(definitions) - 1
i += 1
return blocks
def addmargins(blocks):
"""Adds empty blocks for vertical spacing.
This groups bullets, options, and definitions together with no vertical
space between them, and adds an empty block between all other blocks.
"""
i = 1
while i < len(blocks):
if (blocks[i]['type'] == blocks[i-1]['type'] and
blocks[i]['type'] in ('bullet', 'option', 'field', 'definition')):
i += 1
else:
blocks.insert(i, dict(lines=[''], indent=0, type='margin'))
i += 2
return blocks
def formatblock(block, width):
"""Format a block according to width."""
indent = ' ' * block['indent']
if block['type'] == 'margin':
return ''
elif block['type'] == 'literal':
indent += ' '
return indent + ('\n' + indent).join(block['lines'])
elif block['type'] == 'section':
return indent + ('\n' + indent).join(block['lines'])
elif block['type'] == 'definition':
term = indent + block['lines'][0]
defindent = indent + block['hang'] * ' '
text = ' '.join(map(str.strip, block['lines'][1:]))
return "%s\n%s" % (term, textwrap.fill(text, width=width,
initial_indent=defindent,
subsequent_indent=defindent))
else:
initindent = subindent = indent
text = ' '.join(map(str.strip, block['lines']))
if block['type'] == 'bullet':
initindent = indent + '- '
subindent = indent + ' '
elif block['type'] in ('option', 'field'):
subindent = indent + block['width'] * ' '
return textwrap.fill(text, width=width,
initial_indent=initindent,
subsequent_indent=subindent)
def format(text, width):
"""Parse and format the text according to width."""
blocks = findblocks(text)
blocks = findliteralblocks(blocks)
blocks = findsections(blocks)
blocks = findbulletlists(blocks)
blocks = findoptionlists(blocks)
blocks = findfieldlists(blocks)
blocks = finddefinitionlists(blocks)
blocks = addmargins(blocks)
return '\n'.join(formatblock(b, width) for b in blocks)
if __name__ == "__main__":
from pprint import pprint
def debug(func, blocks):
blocks = func(blocks)
print "*** after %s:" % func.__name__
pprint(blocks)
print
return blocks
text = open(sys.argv[1]).read()
blocks = debug(findblocks, text)
blocks = debug(findliteralblocks, blocks)
blocks = debug(findsections, blocks)
blocks = debug(findbulletlists, blocks)
blocks = debug(findoptionlists, blocks)
blocks = debug(findfieldlists, blocks)
blocks = debug(finddefinitionlists, blocks)
blocks = debug(addmargins, blocks)
print '\n'.join(formatblock(b, 30) for b in blocks)