gistfile1.txt

import re
import sys

class BFBuild(object):
    byte_var_table = {}
    current_var_index = 0
    python = ""

    def __init__(self, python):
        self.python = python

    def process_line(self, line):
        if not re.match("[^ ]", line):
            return
        matches = re.match("print '(.*)'", line)

        if matches:
            self.process_print_static_string(line)
            return

        matches = re.match("print (.+)", line)
        if matches:
            self.process_print_variable(line)
            return

        matches = re.match("([^ ]+)[ ]*=[ ]*'(.)'", line)
        if matches:
            self.process_set_char_variable(line)
            return

        print "Line: ", line
        raise Exception("I only know a little bit of python: print '<string literal>', <variable_name> = '<one char>', print <variable_name>.  Sorry!")

    def process_print_variable(self, line):
        matches = re.match("print (.*)", line)

        variable_name = matches.group(1)

        if variable_name not in self.byte_var_table:
            raise Exception("Undefined variable: %s" % variable_name)

        self.emit_move_to_var_index(self.byte_var_table[variable_name])
        self.emit_print_current_index()
        self.emit_print_string("\n")

    def process_set_char_variable(self, line):
        matches = re.match("([^ ]+)[ ]*=[ ]*'(.)", line)
        value = matches.group(1)

        variable_name = matches.group(1)
        variable_value = matches.group(2)

        if not variable_name in self.byte_var_table:
            # Intentionally leaving cell 0 empty
            self.byte_var_table[variable_name] = len(self.byte_var_table)+1

        self.emit_move_to_var_index(self.byte_var_table[variable_name])
        self.emit_zero_current_index()
        self.emit_set_current_index_value(ord(variable_value))


    def process_print_static_string(self, line):
        matches = re.match("print '(.*)'", line)
        value = matches.group(1)
        self.emit_print_string(value)
        self.emit_print_string("\n")


    def emit_print_string(self, value):
        self.emit_move_to_var_index(0)

        for char in value:
            next_ord = ord(char)
            self.emit_zero_current_index()
            self.emit_set_current_index_value(next_ord)
            self.emit_print_current_index()

    def emit_zero_current_index(self):
        print "[-] Set the current index to 0"

    def emit_set_current_index_value(self, value):
        for i in range(value):
            sys.stdout.write("+")
        print "  Setting value to %s" % value

    def emit_move_to_var_index(self, index):
        if index > self.current_var_index:
            for i in range(index - self.current_var_index):
                sys.stdout.write(">")
            print "Move to variable index %s" % index
        elif index < self.current_var_index:
            for i in range(self.current_var_index - index):
                sys.stdout.write("<")
            print "Move to variable index %s" % index
        else:
            print "noop: Already at variable index %s" % index

        self.current_var_index = index

    def emit_print_current_index(self):
        print "."

    def emit_bf(self):
        for line in self.python.split("\n"):
            self.process_line(line)


s1 = """
var1 = 'H'
var2 = 'e'
var3 = 'l'
var4 = 'l'
ovariable = 'o'

print var1
print var2
print var3
print var4
print ovariable

print 'This is a literal'

var1='m'
var2='o'
var3='d'
var4='i'
ovariable='t'


print var1
print var2
print var3
print var4
print ovariable

"""

BFBuild(s1).emit_bf()