Earlier quoted context omitted.
I was very, very disappointed that the `tap` macro has nothing to do with pattern_tap: https://github.com/mgwidmann/elixir-pattern_tap Basically, in Elixir pipelines are not very friendly to simple destructuring: if a call at the beginning of the pipeline returns a tuple of `{:ok, result}`, you can't use either of shortcut syntaxes for lambdas (&Mod.fun/arity and &Mod.fun(&1)), you have to use `fn` and destructure in…
> if a call at the beginning of the pipeline returns a tuple of `{:ok, result}` In my understanding, pipeline are mostly reserved for “unfailable” operations operating on raw data; whereas the where/else/do macro is more oriented towards errors handling; would it work better in your case?
I think I gave a bad example, the better one would be a function returning datetime in the format of :erlang.localtime: `{{Year,Month,Day},{Hour,Min,Sec}}`. I would like to be able to use this value in a pipeline, by passing only a `{Hour, Min}` tuple to the next call in the pipeline.
With pattern_tap it looks like this:
:erlang.localtime()
|> tap({_, {H,M,_}} ~> {H, M})
|> do_something
`then` macro makes it a bit better, but you still need to create a lambda with the longhand syntax, which is exactly what I wanted to avoid, so it's hardly a solution, even though it may be the best way to do this for now...
EDIT: this is in contrast to Clojure, where maps and vectors are callable, and you get `juxt` in the stdlib. So it's not like pipelines in general can't support convenient extraction of subsets of data flowing through the pipe, it's just that Elixir decided not to support this.