Supercollider

2.1 Debugging

No step debugger, so you have to debug your complex nests of client and server-side code with print statements. That’s the recommended way, and precisely what the debug method does.

Get ready for hours reverse engineering your code to work out what this time caused the Omni Error:

^^ The preceding error dump is for ERROR: Message 'foo' not understood.
RECEIVER: nil

2.2 Not-really-interactive scope

Used to defining variables in a REPL and then using them later?

Try running these two lines, both at once:

var foo="bar";
foo;

You should get back, as you’d expect, bar. Now, run them one at a time. Result:

• ERROR: Variable 'foo' not defined.
    in file 'selected text'
    line 1 char 3:
    foo•;

You can work around this by using “environments”, and other hacks, that is, creating variables as entries in a hash-table with reasonably compact syntax: give them names prepended with a tilde, as, e.g. ~foo. However, this means that you have different syntax and scoping rules between live and library coding. There are more or less two different languages you now have to work with, and neither helps to debug the other particularly much. If, say, you wanted to copy a troublesome method from a class into the interactive document window to step through it and work out where it’s gone wrong (since, as mentioned above, there is no step debugger, this is as good as it gets) you also have to change the syntax and will likely introduce new errors. And so the pain develops from a nagging irritation to a skull-grinding cluster headache.

2.3 Concurrency hell

While Supercollider still has the best sequencer of any language I am aware of, other concurrency and scheduling problems have been solved by the rest of the world while sclang stagnated.

If you code the way that the help files do things, i.e. small numbers of lines of code, each executed manually, you will end up writing code that looks like it works but explodes the moment you try to increase the speed or parallelism with which it is executed. To do anything at all you need to execute it inside a Routine and use server synchronisation to make sure that nothing arrives out of order. However, in my experience this is still not 100% reliable; the entire thing relies on UDP packets which have no particularly useful guarantees about order of arrival or verification of arrival. However, it’s better than nothing; If you don’t do this, sometimes you will get nice, plain errors. More perniciously, sometimes, with patches involving complicated wiring such as Instr and FFTs and such, you put yourself at risk of having things wired together entirely incorrectly, and having hard-to-trace examples of Bus objects full of crosstalk and garbage.

2.4 IO

OSC and MIDI are handled by an elegant evented asynchronous callback system after the latest modern style. Could be better but feels fairly natural, and you can subclass away the rough edges. However for all other IO (file, socket, other network protocols, serial, whatever), it’s blocking access. So if you wish to talk other, more modern protocols, you are without hope, and for that matter, your elegant OSC/MIDI system is caught in the crossfire. In practice you end up running another SC instance to relay pipe contents over OSC.