Deadfish Interpreter

Deadfish is an esoteric programming language that's often the subject of code golfing exercises. Like many other esoteric languages, it only has a few instructions -- i, for incrementing the counter; d, for decrementing the counter; s, for squaring the counter; and o, for outputting the current value of the counter. There is no input instruction.

This simple interpreter acts as an environment for writing Deadfish code. It features a code entry area, an output area and buttons for the instruction set. Your work is automatically saved whenever you close the app. Simple and quick: pretty much what you want from anything like this.