Befunge compiler in Python

1. The program field is a two-dimensional torus, i.e. physically, this is a rectangular matrix of symbol commands closed along the upper (lower) boundary and along the left (right) column. The command pointer moves around the field (each command is a certain character with x, y coordinates), executes the command, and moves on. The movement can be in all 4 directions (by default, right from the point 0,0), and when you go beyond the "field" the pointer appears on the opposite side.
2. There are two commands (p, g) in the language that change the field itself, i.e. the program is "self-rewriting" during execution. The program code at the start may not be equal to the code at the finish. The program “123pgpg ## @” started, and the program “ABC @ 1 @ 2 @ 3.14” (not a correct example) finished working.
3. Chris Pressy noted that he wanted to create a language that was as complex as possible to compile. De facto, it’s true, creating a compiler that makes exe files hellishly difficult for the program, I found information that someone could do it in C ... It’s best to create a translator from the language to the Python code, which I still call compiler for simplicity.

Part 1

from sys import *
import time
import random

1. The sys library is needed in order to get the name of the program file. My compiler was called bbb.py, a test example in the same directory 1.bf, Python version 3.7 itself, and so the program call in the console looked like this: python3 bbb.py 1.bf
2. time , , 0,5-1,0 .
3. random «?» ( ), . -, Befunge - , « » (1 , 2 , 3 , 4 ). « » .

class Pointer:
    def __init__(self, x=0, y=0, vector=2, value=None):
        self.x = x
        self.y = y
        self.vector = vector
        self.value = value
        self.stack = []
        self.stack_sf = 0

    def __str__(self):
        return 'Point ({},{}) vektor:{} value:{} stack_sf:{} stack:{}'.format(self.x, self.y, self.vector, self.value, self.stack_sf, self.stack)

    def step(self):
        if self.vector == 1:
            self.x -= 1
        elif self.vector == 2:
            self.y += 1
        elif self.vector == 3:
            self.x += 1
        elif self.vector == 4:
            self.y -= 1

    def action(self):
	#   ,   

# ===============================
# =                      =
# ===============================

def open_file(name):
    data = open(name, 'r').read()
    return data

def field_print():
    for row in A:
        for elem in row:
            print(elem, end='')
        print()  

# ===========================================
# =                       =
# ===========================================

numbers = ['0', '1', '2', '3', '4', '5', '6', '7', '8', '9']
operators = ['+', '-', '*', '/', '%']
point = Pointer()                           #  
text = open_file(argv[1]).split("\n")       #  
n = len(text)                               # n =  
m = 0                                       # m =  

#    (   m)
for line in text:
    if len(line) > m:
        m = len(line)

#   ( n  m )
A = [' '] * n
for i in range(n):
    A[i] = [' '] * m

#    
for i in range(len(text)):
    for j in range(len(text[i])):
        A[i][j] = text[i][j]

# ==========================================
# =                       =
# ==========================================

# field_print()

while point.value != '@':
    try:
        point.value = A[point.x][point.y]       # 1)    point
        point.action()                          # 2)  
        # print(point)                            # 3) :  
        # time.sleep(0.5)                         # 4) :  0.5 c
    except IndexError:                          #     =  
        print('     ')
        break

# field_print()
print()

1. In the point.value property, the character that is located in array A at the coordinates point.x, point.y is read
2. The point.action () method is called, in which the current (just read) command is executed
3. A pointer is displayed on the screen (all properties)
4. A delay is made before the next iteration (0.1 sec - 0.5 sec)

1. We turned to the stack, and there are no values
2. We accidentally went beyond the program (array) in width or height

Part 2

    def action(self):
	#   ,   

        if self.value == '"' and self.stack_sf == 0:                # ,  "
            self.stack_sf = 1
        elif self.value == '"' and self.stack_sf == 1:
            self.stack_sf = 0
        elif self.stack_sf == 1:                                    # "Hello"   
            self.stack.append(ord(self.value))
        elif self.value in numbers and self.stack_sf == 0:
            # 123   
            self.stack.append(int(self.value))

        elif self.value in operators and self.stack_sf == 0:
            b = self.stack.pop()
            a = self.stack.pop()
            if self.value == '+':
                res = a + b                                         # a+b  
            elif self.value == '-':
                res = a - b                                         # a-b  
            elif self.value == '*':
                res = a * b                                         # a*b  
            elif self.value == '/':
                if b == 0:
                    res = 0
                else:
                    res = a // b                                    # a//b  
            elif self.value == '%':
                res = a % b                                         # a%b  
            self.stack.append(res)

        elif self.value == '!' and self.stack_sf == 0:
            a = self.stack.pop()
            if a == 0:
                a = 1
            else:
                a = 0
            # 0->1, 1->0
            self.stack.append(a)

        elif self.value == '`' and self.stack_sf == 0:
            a = self.stack.pop()        # 
            b = self.stack.pop()        # 
            if b > a:
                res = 1
            else:
                res = 0
            # b>a -> 1|0
            self.stack.append(res)

        elif self.value == '?' and self.stack_sf == 0:
            # ? ( )
            a = random.randint(1, 4)
            self.vector = a

        elif self.value == ':' and self.stack_sf == 0:              #  
            last = self.stack.pop()
            self.stack.append(last)
            self.stack.append(last)

        elif self.value == '\\' and self.stack_sf == 0:             # ab => ba
            a = self.stack.pop()
            b = self.stack.pop()
            self.stack.append(a)
            self.stack.append(b)

        elif self.value == '#' and self.stack_sf == 0:              #  ""
            self.step()

        elif self.value == ',' and self.stack_sf == 0:              # =65=A
            value = self.stack.pop()
            print(chr(value), end='')

        elif self.value == '.' and self.stack_sf == 0:              # Print 
            a = self.stack.pop()
            print(a, end='')

        elif self.value == '_' and self.stack_sf == 0:              #  "_"
            test = self.stack.pop()
            if test == 0:
                #  = 0, (2)
                self.vector = 2
            else:
                #  !=0, (4)
                self.vector = 4

        elif self.value == '|' and self.stack_sf == 0:              #  "|"
            test = self.stack.pop()
            if test == 0:
                self.vector = 3
            else:
                self.vector = 1

        elif self.value == '$' and self.stack_sf == 0:              #  
            self.stack.pop()

        elif self.value == '~' and self.stack_sf == 0:              # Input: A => 65
            val = input(' : ')
            self.stack.append(ord(val[0]))

        elif self.value == '&' and self.stack_sf == 0:              # Input: 65 => 65
            val = int(input(' : '))
            self.stack.append((val))

        elif self.value == 'p' and self.stack_sf == 0:              # x, y, symcode
            x = self.stack.pop()                                    # A(x,y) = symcode
            y = self.stack.pop()
            symcode = self.stack.pop()
            A[x][y] = chr(symcode)

        # x, y, value=A(x,y)
        elif self.value == 'g' and self.stack_sf == 0:
            x = self.stack.pop()                                    # ord(value) => 
            y = self.stack.pop()
            value = A[x][y]
            self.stack.append(ord(value))

        elif self.value == '>' and self.stack_sf == 0:              # >
            self.vector = 2
        elif self.value == '<' and self.stack_sf == 0:              # <
            self.vector = 4
        elif self.value == '^' and self.stack_sf == 0:              # ^
            self.vector = 1
        elif self.value == 'v' and self.stack_sf == 0:              # v
            self.vector = 3
        self.step()                                                 #  

Conclusion

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1. Full code
2. Online version
3. She's in JavaScript
4. Documentation (English)
5. Wiki article (English)