theta8 (formerly named MLang) is a really minimalistic esoteric programming language. Programs are heavily space limited as interpreter accepts them in form of 8x8 bitmaps.
Unlike other esoteric languages which accept images as input, here it is mostly a convension and a somewhat reasonable argument for such a radical space limitation for code (almost like programming a small QR code). Pixels are interpreted linearly from top left corner to down right, no fancy 2D switching of program counter direction or anything like that. There is only basic jump command.
Lack of program space is main obstacle. Shortest commands (like Print or Ask) are two bytes long (two pixels of bitmap). This means that absolute maximum command length of any program is 56/2=28 theta8 commands. Abusing random language features and using as many subroutines and loops is pretty much necessary to write anything more complex than truth-machine (this has one funny consequence, not every command uses all of available modes, so every time I write a new program in theta8 and I am few bytes short on program space I am tempted to just add new RID command mode to the standard, just for this program).
For example FizzBuzz program (it can be found in sample-programs) was made after days of engineering (at first I thought that making it output newlines and making terminate at the same time is impossible).
It uses all 8 variables and 100% of 56 bytes of program space (it only prints F and B instead of full words, but there is just no space for strings here) and I can say that it is the best program that I have ever written in my life ever.
File docs/docs.txt contains full language specification and explanation of all commands. It isn't the best specification ever, but to my defense this thing is so simple that it is mostly selfexplanatory.
In sample-programs directory there are few sample programs written by me that show (underwhelming) capabilities of this language. By interacting with them you get to experience the amazing bitmap obfuscation feature, that when you encode program to theta8 format it is almost impossible to tell what it does at glance or debug it (without carefully writing down it pixel by pixel somewhere else).
Files with .mli extension are written in theta8 intermediate notation (see next paragraph).
src directory contains code of C interpreter that accepts theta8 programs as input. It is called theta8c because previously I made a terrible C++ one (the "barely functional product") and this is an attempt to create good and usable one. This interpreter has options to produce warning (unwanted or undefined behaviours that are handled in potentially unexpected way - like returning when stack is empty), treat them as errors, produce verbose debug output or run in step by step mode.
utilities directory contains transcoder that converts intermediate notation of theta8 to PPM format. Intermediate notation is a simple text notation of theta8 programs. Transcoder is written in AWK and it outputs ASCII PPM bitmaps to stdout. They can't be directly fed to interpreter - it expects binary files. transcode.sh does the neccesary conversion by converting output PPM to BMP and then again to PPM. It relies on ppmtobmp and bmptoppm, it also expects transcoder.awk in the same working directory.
To build interpreter execute make in src directory. To run interpreter execute ./theta8c. To view allowed options run ./theta8c -h.
theta8 was formerly named MLang, but this is a boring name and also there are two other programming languages with that name so I decided to change it.
theta8 programms should have .ppm extension as they are PPM bitmaps. .th8 could be used to signify that this is in fact a program. Or .th8.ppm.
Intermediate notation programs should have .et8 (eta8) extension.