brainfuck

A brainfuck interpreter library. Brainfuck code is first parsed into a simplistic AST. The AST execution continuously augments a virtual machine containing register cells and a pointer to the current position.

Brainfuck input and output respects clojure's *in* and *out*, for instance:

(with-out-str
  (with-in-str "foobar"
    (run "-,+[-.,+]"))) ;; #=> "foobar"

The AST is a simple list of vectors, containing either one or two members. The first member is the character representing the operation, the second member is only present for the \[ operation and contains the branch's code.

The AST interpreter augments a virtual machine implemented as a clojure persistent hash-map with two keys:

• reg: Arbitrary width (grown as needed) register cells
• pos: Current cell offset

The initial virtual machine is thus defined as:

{:reg [0]
 :pos 0}

This library exports three functions:

• parse: Given an input brainfuck program, yields a simplistic AST.
• exec: Augments a virtual machine with the result of the next operation.
• run: Parse and execute a program with an initial virtual machine.

Examples

See the test directory for additional examples

License

Copyright © 2015 Pierre-Yves Ritschard

Distributed under the MIT License, see LICENSE for details.