repr

#!/usr/bin/env python3

import itertools as it, operator as op, functools as ft
import os, sys


def main(args=None):
	import argparse, textwrap

	dedent = lambda text: (textwrap.dedent(text).strip('\n') + '\n').replace('\t', '  ')
	class SmartHelpFormatter(argparse.HelpFormatter):
		def __init__(self, *args, **kws):
			return super().__init__(*args, **kws, width=100)
		def _fill_text(self, text, width, indent):
			if '\n' not in text: return super()._fill_text(text, width, indent)
			return ''.join(indent + line for line in text.splitlines(keepends=True))
		def _split_lines(self, text, width):
			return super()._split_lines(text, width)\
				if '\n' not in text else dedent(text).splitlines()

	parser = argparse.ArgumentParser(
		formatter_class=SmartHelpFormatter,
		description='Run python repr() to stdout on every (text) line of an input file.')
	parser.add_argument('file', nargs='*',
		help='Input file path(s). Stdin is used if none specified or in place of "-".')
	parser.add_argument('-b', '--binary', action='store_true',
		help='Process file lines in binary mode, instead of decoding it with utf-8.'
			' Should allow to see BOM and random'
				' binary goop escaped as individual bytes, not codepoints.')
	parser.add_argument('-n', '--hide-newlines', action='store_true',
		help='Enables "universal newlines" translation and strips last \\n from each line.'
			' Whether this is sufficient for mismatched line endings'
				' depends on how aggressive that mode is in converting newlines.')
	parser.add_argument('-x', '--error-replace', action='store_true',
		help='When decoding stuff (non-binary mode, convert), replace non-decodable chars.')
	parser.add_argument('-c', '--convert',
		const='utf-8', nargs='?', metavar='((enc-src:)enc-dst)(+opts)',
		help='''
			Instead of repr-output, convert encoding
				from enc-src (default=utf-8-sig) to enc-dst (utf-8) and output the result.
			[[enc-src:]enc-dst] spec can be followed by + and any of the following options:
				+r - output windows \\r\\n newlines,
				+i - overwrite file in-place, same as sed -i would do
				+t - trim whitespace from line endings, and ensure final newline
			Examples: -c utf-8-sig+ri, -c +t, -c cp1251:utf-8+it
			Allows to use stuff like utf-8-sig or any other codec supported by python.''')
	opts = parser.parse_args(sys.argv[1:] if args is None else args)

	file_list, file_nl = opts.file, None
	if not file_list: file_list = ['-']

	if opts.convert:
		file_mode = 'rb'
		enc_src, enc_dst, enc_opts = 'utf-8-sig', opts.convert, ''
		if ':' in enc_dst: enc_src, enc_dst = enc_dst.split(':', 1)
		if '+' in enc_dst: enc_dst, enc_opts = enc_dst.split('+', 1)
		if not enc_src: enc_src = 'utf-8-sig'
		if not enc_dst: enc_dst = 'utf-8'
		assert not set(enc_opts).difference('rit'),\
			f'Not all encoding options recognized: {enc_opts}'
		dst_stdout = open(sys.stdout.fileno(), 'wb')
		enc, dec_errors = dict(), 'strict' if not opts.error_replace else 'replace'
	else:
		file_mode = 'r' if not opts.binary else 'rb'
		repr_start = 1 if not opts.binary else 2 # b'' vs ''
		file_nl = ('' if not opts.hide_newlines else None) if not opts.binary else None
		line_end_hide = ('\n' if not opts.binary else b'\n') if opts.hide_newlines else None
		newline='' if not opts.hide_newlines else None
		enc = dict(encoding='utf-8-sig', errors='replace') if opts.error_replace else dict()

	for p in file_list:
		p_file = p != '-'
		with open(
				p if p_file else sys.stdin.fileno(),
				mode=file_mode, newline=file_nl, **enc) as src:
			if opts.convert:
				text = src.read().decode(enc_src, dec_errors).encode(enc_dst)
				while b'\r\n' in text: text = text.replace(b'\r\n', b'\n')
				if 't' in enc_opts:
					text = b'\n'.join(it.chain(
						(line.rstrip() for line in text.rstrip().split(b'\n')), [b''] ))
				if 'r' in enc_opts: text = text.replace(b'\n', b'\r\n')
				if 'i' in enc_opts and p_file:
					with open(p, 'wb') as dst: dst.write(text)
				else: dst_stdout.write(text)
			else:
				for line in src:
					if line_end_hide and line.endswith(line_end_hide): line = line[:-1]
					print(repr(line)[repr_start:-1])

if __name__ == '__main__': sys.exit(main())