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@kaushik20-dev
Forked from elliotchance/brainfuck.py
Created December 28, 2018 02:42
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Write Your Own Brainfuck Compiler
import sys
import ply.yacc as yacc
import ply.lex as lex
tokens = (
'INCREMENT',
'DECREMENT',
'SHIFT_LEFT',
'SHIFT_RIGHT',
'OUTPUT',
'INPUT',
'OPEN_LOOP',
'CLOSE_LOOP',
)
t_INCREMENT = r'\+'
t_DECREMENT = r'-'
t_SHIFT_LEFT = r'<'
t_SHIFT_RIGHT = r'>'
t_OUTPUT = r'\.'
t_INPUT = r','
t_OPEN_LOOP = r'\['
t_CLOSE_LOOP = r'\]'
def t_newline(t):
r'\n+'
t.lexer.lineno += len(t.value)
t_ignore = ' \t'
def t_error(t):
print("Illegal character '%s'" % t.value[0])
t.lexer.skip(1)
def p_commands(p):
"""
commands : command
| commands command
"""
if len(p) == 2:
p[0] = Commands()
p[0].commands = [p[1]]
return
if not p[1]:
p[1] = Commands()
p[1].commands.append(p[2])
p[0] = p[1]
def p_command(p):
"""
command : INCREMENT
| DECREMENT
| SHIFT_LEFT
| SHIFT_RIGHT
| OUTPUT
| INPUT
| loop
"""
if isinstance(p[1], str):
p[0] = Command(p[1])
else:
p[0] = p[1]
def p_loop(p):
"""
loop : OPEN_LOOP commands CLOSE_LOOP
"""
p[0] = Loop(p[2])
def p_error(p):
print("Syntax error in input!")
class BrainfuckProgram:
def __init__(self, source):
self.source = source
def run(self):
self.data = [0] * 20
self.location = 0
commands = self.parse(self.source)
commands.run(self)
def parse(self, source):
lexer = lex.lex()
parser = yacc.yacc()
return parser.parse(source)
def __str__(self):
return str(self.parse(self.source))
class Commands:
def __init__(self):
self.commands = []
def run(self, program):
for command in self.commands:
command.run(program)
def __str__(self):
return ''.join([str(command) for command in self.commands])
class Command:
def __init__(self, command):
self.command = command
def run(self, program):
if isinstance(self.command, Loop):
self.command.run(program)
if self.command == '+':
program.data[program.location] += 1
if self.command == '-':
program.data[program.location] -= 1
if self.command == '<':
program.location -= 1
if self.command == '>':
program.location += 1
if self.command == '.':
sys.stdout.write(chr(program.data[program.location]))
def __str__(self):
return self.command
class Loop:
def __init__(self, commands):
self.commands = commands
def run(self, program):
while program.data[program.location] != 0:
self.commands.run(program)
def __str__(self):
return '[' + str(self.commands) + ']'
source = '++++++++[>++++[>++>+++>+++>+<<<<-]>+>+>->>+[<]<-]>>.>---.+++++++..+++.>>.<-.<.+++.------.--------.>>+.>++.'
program = BrainfuckProgram(source)
program.run()
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