Pretty print markdown file (useful with text editors without printing)

md-pp.py

#!/usr/bin/env python3
# -*- coding: utf-8 -*-
# (c) Copyright 2016 by Joseph Reagle
# Licensed under the GPLv3, see <http://www.gnu.org/licenses/gpl-3.0.html>
#
"""Pretty print a markdown file as line-numbered source.

Perhaps one day replace with a [panflute] filter for pandoc.

[panflute]: http://scorreia.com/software/panflute/
"""

import html
import io
import logging
import markup  # https://tylerbakke.github.io/MarkupPy/
from markup import oneliner as o
import os
from os import chdir, environ, mkdir, rename
from os.path import abspath, basename, dirname, expanduser, isfile, realpath, splitext
import re
import webbrowser

HOME = environ["HOME"]
TMP_DIR = environ["TMPDIR"]

critical = logging.critical
info = logging.info
dbg = logging.debug
warn = logging.warn
error = logging.error
excpt = logging.exception

# Main ####################################


def process(args, filename):

    info("filename = %s" % filename)
    assert isfile(filename)
    base_name = basename(filename)
    bald_name = splitext(base_name)[0]
    # output_dir = dirname(realpath(filename))
    output_dir = TMP_DIR
    info("base_name = %s" % base_name)
    info("bald_name = %s" % bald_name)
    info("output_dir = %s" % output_dir)
    html_fn = os.path.join(output_dir, bald_name + "-pp.html")
    info("output_dir = %s; html_fn = %s" % (output_dir, html_fn))

    with io.open(filename, "r", encoding="utf8") as f:
        lines = f.readlines()

    page = markup.page()
    page.init(
        title=lines[0],
        css=("http://reagle.org/joseph/2016/06/md-pp.css"),
        charset="utf-8",
    )

    in_comment = in_table = False
    margin_markup = re.compile(r"(^[#>: ]+)(.*)")
    for line_no, line in enumerate(lines, start=1):
        line = html.escape(line)

        if not in_table and line.startswith("+--"):
            in_table = True
            page.pre.open()
            pre_lines = []
            pre_lines.append(line)
            continue
        if in_table:
            if not line.strip():  # if blank line (not empty)
                page.add("".join(pre_lines))
                page.pre.close()
                in_table = False
            else:
                pre_lines.append(line)
            continue

        if "&lt;!--" in line and "--&gt;" not in line:  # start comment
            line = line.replace("&lt;!--", '<span class="comment">&lt;!--')
            line = line + "</span>"
            in_comment = True
        elif "&lt;!--" not in line and "--&gt;" in line:
            line = line.replace("--&gt;", "--&gt;</span>")  # end comment
            line = '<span class="comment">' + line
            in_comment = False
        elif "&lt;!--" in line and "--&gt;" in line:  # full comment
            line = line.replace("&lt;!--", '<span class="comment">&lt;!--')
            line = line.replace("--&gt;", "--&gt;</span>")
        elif in_comment:  # in_comment
            line = '<span class="comment">' + line + "</span>"

        if not line.strip():  # empty line
            page.p(("&nbsp;"))
        elif margin_markup.match(line):
            token = margin_markup.match(line).group(1)
            if token.startswith("#"):
                if len(token) == 2:
                    page.h1(line)
                elif len(token) == 3:
                    page.h2(line)
                elif len(token) == 4:
                    page.h3(line)
                else:
                    page.h4(line)
            elif token.startswith(">"):
                page.blockquote(line, class_="quote")
            elif token.startswith(":"):
                page.blockquote(line, class_="definition")
            elif token.startswith("  "):
                left_margin = len(token) / 2
                page.p.open(style="margin-left: %dem" % left_margin)
                page.span(line_no, class_="line_no")
                page.span(line.strip(), class_="prose")
                page.p.close()

        else:
            page.p.open()
            page.span(line_no, class_="line_no")
            page.span(line, class_="prose")
            page.p.close()

    with io.open(html_fn, "w", encoding="utf8") as f:
        f.write(str(page))

    webbrowser.open("file://" + html_fn)


if "__main__" == __name__:

    import argparse  # http://docs.python.org/dev/library/argparse.html

    arg_parser = argparse.ArgumentParser(
        description="Pretty print a markdown file as source"
    )

    # positional arguments
    arg_parser.add_argument("files", nargs=1, metavar="FILE")
    # optional arguments
    arg_parser.add_argument(
        "-L",
        "--log-to-file",
        action="store_true",
        default=False,
        help="log to file %(prog)s.log",
    )
    arg_parser.add_argument(
        "-V",
        "--verbose",
        action="count",
        default=0,
        help="Increase verbosity (specify multiple times for more)",
    )
    arg_parser.add_argument("--version", action="version", version="0.1")
    args = arg_parser.parse_args()

    log_level = 100  # default
    if args.verbose == 1:
        log_level = logging.CRITICAL  # 50
    elif args.verbose == 2:
        log_level = logging.INFO  # 20
    elif args.verbose >= 3:
        log_level = logging.DEBUG  # 10
    LOG_FORMAT = "%(levelno)s %(funcName).5s: %(message)s"
    if args.log_to_file:
        logging.basicConfig(
            filename="md-pp.log", filemode="w", level=log_level, format=LOG_FORMAT
        )
    else:
        logging.basicConfig(level=log_level, format=LOG_FORMAT)

    process(args, args.files[0])