Stacks, Queues - Monty

The Monty language

Monty 0.98 is a scripting language that is first compiled into Monty byte codes (Just like Python). It relies on a unique stack, with specific instructions to manipulate it. The goal of this project is to create an interpreter for Monty ByteCodes files.

Monty byte code files

Files containing Monty byte codes usually have the .m extension. Most of the industry uses this standard but it is not required by the specification of the language. There is not more than one instruction per line. There can be any number of spaces before or after the opcode and its state.argument:

kael@think:~$ cat -e bytecodes/000.m
push 0$
push 1$
push 2$
  push 3$
pall $
push 4$
push 5 $
      push    6        $
pall$
kael@think:~$

Monty byte code files can contain blank lines (empty or made of spaces only), and any additional text after the opcode or its required state.argument is not taken into account:

kael@think:~$ cat -e bytecodes/001.m
push 0 Push 0 onto the stack$
push 1 Push 1 onto the stack$
$
push 2$
push 3$
                   pall    $
$
$
                           $
push 4$
$
    push 5    $
      push    6        $
$
pall This is the end of our program. Monty is awesome!$
kael@think:~$

The monty program

• Usage: monty file
  • where file is the path to the file containing Monty byte code
• If the user does not give any file or more than one state.argument to the program, the program prints the error message USAGE: monty file, followed by a new line, and exit with the status EXIT_FAILURE
• If, for any reason, it’s not possible to open the file, the program prints the error message Error: Can't open file <file>, followed by a new line, and exit with the status EXIT_FAILURE where <file> is the name of the file
• If the file contains an invalid instruction, the program prints the error message L<line_number>: unknown instruction <opcode>, followed by a new line, and exit with the status EXIT_FAILURE where line_number is the line number where the instruction appears.
• Line numbers always start at 1
• The monty program runs the bytecodes line by line and stop if either:
  • it executed properly every line of the file
  • it finds an error in the file
  • an error occured
• If the program can’t malloc anymore, it prints the error message Error: malloc failed, followed by a new line, and exit with status EXIT_FAILURE.

Authors

Michael Peter