Monty

monty is an interpreter of Monty ByteCodes files, which is a scripting language just like Python.

About the Monty language

This is a language that contains specific instructions to manipulate data information (stacks or queues), where each instruction (called opcode) is sended per line. Files which contains Monty byte codes usually have the .m extension.

Example (file.m):

$ cat file.m
# Pushing element to the stack
push 0
push 1
push 2
# Printing all elements
pall
push 3
push 4
pop
# Rotating the stack to the bottom
rotr
pall
rotl
# Setting FIFO
queue
push 5
# Setting LIFO
stack
push 5
$

Technologies

• Interpreter was written with C language
• C files are compiled using gcc 4.8.4
• C files are written according to the C90 standard
• Tested on Ubuntu 14.04 LTS

Usage

To compile all files:

$ gcc -Wall -Werror -Wextra -pedantic *.c -o monty
$

The synopsis of the interpreter is the following:

$ ./monty [filename]
$

To run the interpreter:

$ ./monty file.m
2
1
0
0
3
2
1
$

Features

Opcodes

monty executes the following opcodes:

Opcode	Description
push	Pushes an element to the stack
pall	Prints all the values on the stack
pint	Prints the value at the top of the stack
pop	Removes the top element of the stack
swap	Swaps the top two elements of the stack
queue	Sets the format of the data to a queue (FIFO)
stack	Sets the format of the data to a stack (LIFO)
nop	Doesn't do anything
add	Adds the top two elements of the stack
sub	Subtracts the top element of the stack from the second top element of the stack
mul	Multiplies the second top element of the stack with the top element of the stack
div	Divides the second top element of the stack by the top element of the stack
mod	Computes the rest of the division of the second top element of the stack by the top element of the stack
pchar	Prints the char at the top of the stack
pstr	Prints the string starting at the top of the stack
rotl	Rotates the stack to the top
rotr	Rotates the stack to the bottom

Comments, indicated with #, are not executed by the interpreter.

When a nonextistent opcode is passed, the interpreter prints an error message and stops:

$ cat errorfile.m
push 1
pint
pcx
$ ./monty errorfile.m
1
L3: unknown instruction pcx

Return value

When there is no errors, monty returns 0. Otherwise, returns 1

Authors

• Jorge Zafra: Twitter - GitHub
• Luis Chaparro: Twitter - GitHub