Formin
| Designed by | User:CapinolDev |
|---|---|
| Appeared in | 2025 |
| Computational class | Turing-complete |
| Reference implementation | https://github.com/CapinolDev/Formin/blob/main/interpreter.f95 |
| File extension(s) | .fmn |
Formin is an esoteric programming language created by User:CapinolDev in 2025.
It uses a symbolic, label-driven syntax with commands enclosed between #/ and /#.
Programs are executed sequentially, but can jump between labeled sections using mark# and go# commands, creating a unique flow-based execution model.
Overview
Formin source files use a compact, tokenized structure:
command#/token1|token2|token3/#
Strings are enclosed in single quotes ('text'), while variables are referenced directly.
Example:
create#/greeting|'Hello, World!'/# spew#/greeting/# bye
Computational class
Formin is Turing-complete because it supports arbitrary loops (`mark#/go#/ifgo#`), mutable variables, and conditional branching, allowing it to simulate a Minsky machine.
Example
A simple Tic-Tac-Toe program demonstrates how Formin handles variables, branching, and flow markers:
create#/validator|0/# create#/checkNum|0/# color#/green/# spew#/Welcome to tic tac toe!/# color#/reset/# go#/initBoard/# mark#/initDone/#
(Full example available on the GitHub repository.)
Commands
| Command | Description |
|---|---|
create# |
Define or update a variable. |
spew# |
Print text with automatic spaces. |
spewmult# |
Print without automatic spacing. |
color# |
Change terminal color (e.g. green, red, reset). |
mark# |
Define a label to jump to. |
go# |
Jump to a marker. |
ifgo# |
Conditional jump using is, isnt, >, <, etc.
|
add#, sub#, mult#, div# |
Basic arithmetic operations. |
ask# |
Prompt the user and store input in a variable. |
open#, read#, close# |
Simple file handling commands. |
clear# |
Clear the terminal screen. |
bye |
Terminate execution. |
Implementation
The official Formin interpreter is written in Fortran 95. It performs a two-pass parse:
- Scans all
mark#/labels. - Executes each command sequentially with conditional branching support.
The interpreter and example programs are available on GitHub.
License
- Interpreter — MIT License
- Logo — CC BY-SA 4.0
- Documentation — CC BY-SA 4.0