BrainFuck interpreter

# -*- coding: utf-8 -*-
"""
Created on Fri May 25 00:26:37 2018

@author: Mauro
"""

# BrainFuck interpreter

# have a pointer that will travel an array
class Pointer:

    def __init__(self):
        self.p = 0
        self.arr = [0 for i in range(10)]

    # >
    def increment(self):
        self.p += 1

    # <
    def decrement(self):
        self.p -= 1

    # +
    def increase(self):
        self.arr[self.p] += 1

    # -
    def decrease(self):
        self.arr[self.p] -= 1
    # .
    def putc(self, outstream):
        output = self.arr[self.p]
        print("OUTPUT:", output)
        outstream.append(output)
    # ,
    def getc(self):
        i = input("INPUT:")
        self.arr[self.p] = i[0]

    def get_value(self):
        return self.arr[self.p]


class Instructions:

    def __init__(self, program):
        # the underlying pointer that moves on the array
        self.p = Pointer()

        # the string corresponding to the program
        self.prog = program

        # the instruction pointer
        self.ip = 0

        # parentheses stack
        self.pstack = []
        self.pcount = 0
        self.current_pcount = 0

        # the output stream
        self.out_stream = []

    # equivalent to char* c; *c++
    # returns null when the end of the string is reached
    def getc(self):
        if self.ip < len(self.prog):
            c = self.prog[self.ip]
            self.ip += 1
            return c
        else:
            return None

    # runs the program
    def interpret(self):

        c = self.getc()
        while c:
            print("-------", c, self.ip, "--------")

            if c == ">":
                self.p.increment()
            elif c == "<":
                self.p.decrement()
            elif c == "+":
                self.p.increase()
            elif c == "-":
                self.p.decrease()
            elif c == ".":
                self.p.putc(self.out_stream)
            elif c == ",":
                self.p.getc()
            elif c == "[":

                # puts the character index where the loop start
                known_starts = [start for start, end in self.pstack]
                if self.ip in known_starts:
                    pass
                else:
                    self.pstack.append([self.ip, -1])

                self.current_pcount = self.pcount
                self.pcount += 1

                # if the value of the pointer is 0 and the end instruction pos
                # is not known then eat characters till you find the matching
                # parentheses
                if self.p.get_value() == 0 and self.pstack[self.current_pcount][1] == -1:
                    c = self.getc()
                    # eat characters till the next MATCHING ]
                    while c:
                        if c == "[":
                            self.pcount += 1
                        elif c == "]":
                            self.pcount -= 1
                            # if the program finds the matching parenthes
                            if self.current_pcount == self.pcount:
                                break
                        c = self.getc()

                # if the end is known go to end
                elif self.p.get_value() == 0:
                    # end of loop
                    self.ip = self.pstack[self.current_pcount][1]

                    # pop the parentheses out of the stack (loop is skipped)
                    self.pstack.pop(len(self.pstack)-1)
                    self.pcount -= 1

            elif c == "]":
                self.pcount -= 1
                self.pstack[self.pcount][1] = self.ip

                # if the value is different then zero jump back to the
                # loop start
                if self.p.get_value != 0:
                    self.ip = self.pstack[self.pcount][0] -1


            c = self.getc()
            # print the array
            print("".join([str(i) + "|" for i in self.p.arr]))
            # print the pointer position

            p_arrow = ""

            for i in range(len(self.p.arr)):
                # get the char length of the cell
                cellc = len(str(self.p.arr[i]))
                formatspec = "{:-^" + str(cellc) +"}|"
                if self.p.p == i:
                    if cellc % 2 == 0:
                        cell = formatspec.format("^^")
                    else:
                        cell = formatspec.format("^")

                else:
                    cell = formatspec.format("")
                p_arrow += cell
            print(p_arrow)

        print(self.out_stream)
        print("".join([chr(c) for c in self.out_stream]))


if __name__ == "__main__":

#     bfi = Instructions("++>+++++[<+>-]++++ ++++[<+++ +++ >-]<.")
#     bfi = Instructions("++++[>++++[-]<-]")

     bfi = Instructions("++++++++[>++++[>++>+++>+++>+<<<<-]>+>+>->>+[<]<-]>>.>---.+++++++..+++.>>.<-.<.+++.------.--------.>>+.>++.")

     bfi.interpret()