FIM++ is an esoteric programming language inspired by the cartoon My Little Pony: Friendship is Magic. In the early episodes of the show, the unicorn Twilight Sparkle is regularly seen writing letters to her mentor, princess Celestia. In the letters she often reports on the latest lessons she learned in her studies of the magic of friendship or the adventures of her and her friends.
The programs in FIM++ are made to resemble these letters. FIM++ is an imperative, dynamically-typed, interpreted language. Currently, it supports integer arithmetic, console output, dynamically growing arrays, and subroutines. FIM++ programs can also use arbitrary Java classes, which opens it to the rich and wide JVM ecosystem. This, for instance, makes it possible to write a simple graphical program using Swing.
The language's syntax leaves some freedom for the programmer, allowing them to make their programs look more like a coherent letter to a pony princess. For example, the traditional Hello, World! written in FIM++ might look like this:
Dear Princess Celestia: An example letter.
Today I learned about greetings:
I said "Hello, Equestria".
Your faithful student, Twilight Sparkle.
You can find more involved examples under the examples subdirectory,
including famous algorithms such as the Sieve of Eratosthenes and Quicksort.
There you can also find an implementation of the Brainfuck interpreter,
which proves the Turing completeness of the FIM++ language.
The original FIM++ interpreter was created by @KarolS on GitHub. It was inspired by a post by Cereal Velocity on Equestria Daily and some example programs written by DeftCrow and others on DeviantArt. See also the FIM++ page at the Esolang Wiki.
You will need the Scala compiler and the Java Development Kit (JDK) to build the fimpp interpreter from source. Be warned that there are some known problems when using newer Scala and Java versions (any contributions in that regard would be most welcome). Scala 2.9.2 and OpenJDK 7 in Debian Jessie are known to work. If you have problems getting things to play nicely, see Running from Docker below.
On a Debian GNU/Linux system, the Scala compiler can be installed with the following command:
$ sudo apt-get install scala
The easiest way to compile the FIM++ interpreter is to use the provided Makefile:
$ make
And that's all! A freshly compiled fimpp.jar should land in your bin
directory!
If you want to compile it manually (e.g. there is no make on your system),
follow these steps. These steps should also work on Windows:
$ mkdir target
$ scalac -d target src/stasiak/karol/fimpp/*
$ cd target
$ jar cfe ../bin/fimpp.jar stasiak.karol.fimpp.Main stasiak
If you want to make sure everything works as expected, run some tests:
$ make test
In the bin directory, there are all necessary scripts to run this interpreter
on any machine with Java installed. To run the interpreter with a given FIM++
source file from your command line on a Linux system:
$ bin/fimpp <FIM++ script file>
There is also a fimpp.bat available for running on Windows.
There is a Docker container with fimpp available. This should make it possible to run fimpp on any machine capable of running Docker containers, regardless of Java version conflicts. However this does come at a price of a hefty download.
First pull the container from Docker Hub:
$ docker pull avian2/fimpp
After that, you can run the 99bottles.fimpp example like this:
$ docker run avian2/fimpp examples/99bottles.fimpp
Or to run your own program letter.fimpp (that you saved into the current
working directory):
$ docker run -v `pwd`/letter.fimpp:/letter.fimpp avian2/fimpp /letter.fimpp
See the examples directory for example programs that demonstrate practically
all features of the language.
The language is reasonably well documented in the syntax directory. The best
approach to understanding the language is to study the examples with the help
of these documents.
There is also a (currently incomplete) attempt at a formal grammar
description for FIM++ in grammar/bnf.pdf.
fimpp, a FIM++ pony language interpreter
Copyright (C) 2017 Karol Stasiak and other contributors
This program is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version.
This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.
You should have received a copy of the GNU General Public License along with this program. If not, see http://www.gnu.org/licenses/.