In Racket/Scheme is dependency injection seen as idiomatic?

For example if you have a function that uses a random number it is easier to test if the random number generator is supplied to the function as you can supply a known sequence for your tests.

Basic example

(define (random-example) (random 10))

(define (random-example2 generator-lambda) (generator-lambda 10))

usage

(random-example)

(random-example2 (λ (x) (random x)))

@mark.warren probably the idiomatic way to do things like that would be a parameter

and/or an optional argument to random

in fact, that’s how random works already — it takes an optional second argument which is the generator, and the default behavior is to look up the current value of a parameter

@samth Thank you, I was using random as an example, but that information is good to know. I was wondering really if DI is idiomatic Racket.

I feel like dependency injection means a lot of things to different people

but the pattern that random uses is pretty idiomatic

@samth Indeed you are correct. I think I see what you are getting at now. Have an optional argument so that you can supply the generator if you want else use the default.

and also you can change the default for a whole bunch of code with parameterize

Thanks