i'm with the gp. i guess another way i think about it (which might be wrong, please tell me) is that with monads we can talk treat something like pipe as a pure object, even though whats its carrying is decidely not
Yup, exactly. It's basically like if you have a bunch of simple arithmetic functions:
half(x)
double(x)
triple(x)
you can easily do things like:
double(half(triple(13)))
Or a la pipes:
triple 13 | half | double
But now what if you want to print something in `half` without a global? Well, I guess it's half(x, printer) now. Hmm and now `triple` has to carry that around too, so it's triple(x, printer). Well, that makes me think everything gets a printer, so it's double(x, printer) now too.
Well, printing is cool, but now we're a real company and real companies log everything. I... guess we're making new functions? half_log(x, logger) and triple_log(x, logger) and double_log(x, logger). And... new pipelines? Ugh.
At this point you might be thinking one of a number of things:
- Are globals really that bad?
- Can OOP fix this (dependency injection, builders)?
- Surely there's some kind of framework for this.
And if you're a functional programmer who's super not into globals or OOP, you might start seeing the appeal of #3 there. Et voila, a whole bunch of functions that handle this "pass an extra blob into your pipelines" thing.
