Python Subleq Interpreter

Written by Chris Lloyd in Python 3.3

Released under the GNU General Public License

What is Subleq?

Simply put it's a one instruction language. Learn more here:

• http://esolangs.org/wiki/Subleq
• http://mazonka.com/subleq/
• http://en.wikipedia.org/wiki/One_instruction_set_computer

Why Subleq?

I found it interesting that the subleq instruction is able to emulate many other common instructions seen in other languages such as assembly. After reading about it I wanted to play around with it, but I could only find a few parsers and interpreters so I wrote my own.

Contents Overview

• SubleqParser: Takes subleq input and outputs integer array for the virtual machine
• SubleqVM: Interpreters output from SubleqParser
• subleq.py: Provides command-line interface for interpreting subleq code

Basic Examples:

Create a file called input.subleq containing:

# Hello world!
# Taken with modifications from http://mazonka.com/subleq/

# output *p; 
a; p Z; Z a; Z
a:0 -2

# p++
m1 p;

#check if p<E
a; E Z; Z a; Z;
p a -2

Z Z -2

. p:H Z:0 m1:-1
. H: "Hello, World!" 10 E:E

Make sure subleq.py, subleq_parser.py, and subleq_vm.py are in the same folder, then in the console type: python subleq.py input.subleq This should produce the output Hello, World!

Implementation specifics

# Special Characters 
# ? pointers to the next instruction
# . tells the parser the line has no instructions
# : defines labels in the form label_name:

# Implied Instructions
a      # equals a a ?
a b    # equals a b ?
a b c  # equals a b c

# Special Address Examples
a -2   # outputs value stored at a, in this case 0
a -1   # gets input and stores it in a
z z -2 # exits the program by jumping to -2
. z:0 a:0