"""
 vtm2yvtm.py

 Convert *.vtm to *.yvtm

 -txxx  => tape: "xxx"
 -bx    => blank: x
 -sxxx  => start: xxx
           accept: []
           reject: []

 #xxx   => #xxxx

Most lines in the files are rules.
Preface all of them with machine: , 
then convert

state, symbol,    new_state,    new_symbol,   R | L

to 

   - [ state, symbol,    new_state,    new_symbol,   right | left ]

usage:

  $ python vtm2yvtm.py < filename.vtm  > filename.yvtm

Tested with python 3.7.

Jim Mahoney | cs.marlboro.college | Oct 2019 | MIT License

"""
from sys import stdin, stdout
import re

stdout.write('# \n')
stdout.write('# -- vtm2vtym -- \n')
stdout.write('# \n')
stdout.write('\n')

has_blank = has_tape = has_start = has_machine = False

for line in stdin:

    line = line.strip()
    
    match_blank = re.match(r'.*-b(.)', line)
    if match_blank:
        blank = match_blank.group(1)
        stdout.write('blank: "{}"\n'.format(blank))
        has_blank = True

    match_tape = re.match(r'.*-t([^ ]+)', line)
    if match_tape:
        tape = match_tape.group(1)
        stdout.write('tape: "{}"\n'.format(tape))
        has_tape = True

    match_start = re.match(r'.*-s([^ ]+)', line)
    if match_start:
        start = match_start.group(1)
        stdout.write('start: "{}"\n'.format(start))
        has_start = True

    if line and not line[0] == '#':
        if not has_machine:
            stdout.write('\n')
            stdout.write('machine: \n')
            stdout.write('\n')
            has_machine = True
        line = line.replace('L', 'left')
        line = line.replace('R', 'right')
        line = '  - [ ' + line + ']'
    
    stdout.write(line + '\n')

stdout.write('\n')
    
if not has_blank:        
    stdout.write('blank: "_"\n')

if not has_start:
    stdout.write('start: ""\n')

if not has_tape:
    stdout.write('tape: ""\n')

stdout.write('accept: []\n')
stdout.write('reject: []\n')

stdout.write('\n')