Noisefunge: A music programming environment in Befunge

NoiseFunge

NoiseFunge is an obfuscated language for music livecoding. It is a member of the befunge family of languages. Some features of the language are:

• Terse, visually striking syntax.
• Animation of running programs.
• MIDI support (ALSA).
• A lightweight VM capable of supporting thousands of threads.
• Network-based runtime control.

Here's an example noisefunge video: https://www.youtube.com/watch?v=9zObiWi4Mbw

Installation

Currently, the recommended method for installing NoiseFunge is to use cabal to install the executable into a sandbox. The following steps can be used to install NoiseFunge. However, this method may still require installation of system packages for alsa and ncurses.

git clone https://github.com/revnull/noisefunge.git

cd noisefunge

cabal sandbox init
cabal build
cabal install

Executables

If NoiseFunge is installed in a cabal sandbox, then the noisefunge.env file can be used to add the executables to the PATH and configure environmental variables for communicating with a running NoiseFunge program over the loopback network (port 4545).

funged

This is the NoiseFunge runtime daemon. It requires a config file specifying the tempo and network interfaces. An example named test.cfg is provided in the source repository.

nfops

This program lists all of the operators built in to NoiseFunge.

nfloader

This program loads a NoiseFunge file into the VM. The required command line parameters are a filename, and names of input and output buffers.

nfkill

This program kills a NoiseFunge process in the VM. There are three ways to run this.

• nfkill kills all processes
• nfkill -n FILENAME kills all processes matching the given filename
• nfkill -p PID kills the process with the specified PID

nftop

This is the "top-like" program for inspecting the VM.

nfviewer

This is the process animator. The only controls are:

• r or R to re-tile the processes.
• q or Q to quit.

NoiseFunge opcodes

The NoiseFunge VM supports several opcodes that are not standard in befunge-98.

A-F

NoiseFunge supports opcodes for A-F that work like the 0-9 opcodes but push the corresponding hex values onto the stack.

Fork

The K opcode forks a new process. The number 0 is pushed onto the parent's stack and 1 is pushed onto the child's stack.

Call

The c opcode is similar to the g opcode, but instead of accessing a byte from memory and pushing it onto the stack, the c opcode instead executes that byte as an opcode.

Execute

The e opcode pops a value off of the stack and executes it as an opcode.

I/O and buffers

NoiseFunge utilizes a non-standard form of input and output. Each process is assigned to one input buffer and one output buffer. Opcodes can be used to read and write from these buffers. Each process also has its own text buffer for writing characters and numbers.

• ~ reads a byte from the input buffer and pushes it onto the stack. This blocks if there is no process writing to the buffer.
• . pops a byte from the stack and writes it to the output buffer. This blocks if there is no process reading from the buffer.
• ; pops a byte from the stack and sends it to all processes waiting on the output buffer. This does not block.
• , pops a byte and writes it to the text buffer.
• & pops a byte and outputs it as a base 10 number to the text buffer.

Note buffer opcodes

The note buffer is a virtual device that can be read, written, or played through the use of opcodes.

• z pops duration, velocity, pitch, and channel and writes them to the note buffer.
• Z plays the note in the note buffer.
• y pops a value off of the stack and sets the notebuf channel.
• Y reads the channel from the notebuf and pushes it to the stack.
• x pops a value off of the stack and sets the notebuf pitch.
• X reads the pitch from the notebuf and pushes it to the stack.
• w pops a value off of the stack and sets the notebuf velocity.
• W reads the velocity from the notebuf and pushes it to the stack.
• u pops a value off of the stack and sets the notebuf duration.
• U reads the duration from the notebuf and pushes it to the stack.

Conditional trampoline

• ' pops a value and jumps over the next opcode iff the value is 0.

Quantize and sleep

• q sleeps until the next beat is reached.
• Q pops a value and sleeps until a beat divisible by the popped number.
• s pops a number and sleeps for that many subbeats.

User-defined opcodes

The [ opcode work similar to the quote operator. [ causes bytes to be pushed onto a "function definition stack". Another [ pops the first value off of the function definition stack and uses this as the name of the opcode being defined. The rest of the items in the stack become the opcodes used by the function in the order they are popped off of the stack.

Some examples:

• [x*5Cc[ defines the opcode c that writes middle C to the note buffer
• [*:p[ defines the opcode p that squares the top value on the stack

Function definition is global. A function defined in one thread will be visible to another thread. This can lead to interesting behavior when multiple threads are rewring a function. This also makes functions another type of IPC supported by NoiseFunge.

The semantics of this feature are pretty poorly thought out and some combinations may lead to bizarre or unpredictable behavior. Some notes are listed below.

• Opcode definitions are computed as soon as the second [ is encountered. At this point, the opcode is defined based on the function of the opcodes at the point when it is defined.
• User-defined opcodes execute in a single clock tick. Exceptions are opcodes that utilize the quantize/sleep opcodes: q, Q, and s.
• ' and # will take effect at the end of the execution of the opcode.
• Builtin opcodes can be overwritten for exciting results.

from Hacker News https://ift.tt/1DQoYHX