Format latex with one sentence per line

format-latex.py

import re
import sys

import pyparsing as pp

escaped = pp.Combine(
    pp.Literal('\\') + pp.CharsNotIn('', exact=1)).setResultsName('percent').leaveWhitespace()
comment = pp.Combine(pp.Literal('%') + pp.restOfLine).setResultsName('comment').leaveWhitespace()
args = pp.Forward()
group = pp.Forward()
cmd = pp.Group(pp.Or([
        escaped.setResultsName('cmd_name'),
        pp.Combine(pp.Literal('\\') + pp.Word(pp.alphas, pp.alphanums + '_')).setResultsName('cmd_name') +
        pp.Group(pp.Or([
            pp.OneOrMore(args),
            pp.FollowedBy(pp.CharsNotIn(pp.alphanums + '_'))
        ])).setResultsName('args')
    ])).setResultsName('cmd')
text = pp.CharsNotIn(r'\%{}').leaveWhitespace()
in_arg_text = pp.CharsNotIn(r'\%{}[]<>').leaveWhitespace()
in_arg = pp.ZeroOrMore(pp.MatchFirst([cmd, comment, args, in_arg_text])).leaveWhitespace()
latex = pp.ZeroOrMore(pp.MatchFirst([cmd, comment, group, text])).leaveWhitespace()
group << (pp.Literal('{') + latex + pp.Literal('}')).leaveWhitespace()
args << pp.Or([
        pp.Literal('{') + in_arg + pp.Literal('}'),
        pp.Literal('[') + in_arg + pp.Literal(']'),
        pp.Literal('<') + in_arg + pp.Literal('>')
    ]).leaveWhitespace()


context = []
def format(x):
    if type(x) is str:
        is_para = x[0] not in r'\{}%'
        for env in ['figure', 'table', 'equation']:
            if env in context or env + '*' in context:
                is_para = False
        if is_para:
            x = re.sub('\\b\\s+[\r\n]+', ' ', x)
            x = '\n'.join(re.split(r'(?<=[.?!])\s+\b', x))
            # print(re.split(r'(?<=[.?!])\s+', x))
        sys.stdout.write(x)
    else:
        if x.getName() == 'cmd' and x['cmd_name'] == r'\begin':
            context.append(x['args'][1])
        for y in x:
            format(y)
        if x.getName() == 'cmd' and x['cmd_name'] == r'\end':
            assert context.pop() == x['args'][1]

format(latex.parseFile(sys.argv[1]))