I know this has been discussed before, in different forms, but I thought
I’d just have another go following my recent earth-shattering PR :)
I’d like to propose a new unary operator, &>. It works just like the
pipeline |>, but doesn’t take a left argument. Instead it returns an arity
1 function that, when called, executes the pipeline.
toCamel = &> downcase |> split("_") |> map(&capitalize/1) |> join
toCamel.("now is") # => "NowIs""the_time" |> toCamel.() # => "the
time"
Why?
-
Function composition is a key part of FP. It would be nice to support it
natively.
-
The current pipeline semantic both defines a processing flow *and
executes it*. Splitting this into two would allow a lot more
expressiveness.
-
This would allow pipelines to be composed. Think Plug, but functional .
pipeline :browser do
plug :accepts, ["html"]
plug :fetch_session
plug :fetch_flash
plug :protect_from_forgeryend
would become
browser_pipeline =
&> accepts("html") |> fetch_session |> fetch_flash |> protect_from_forgery
The cool thing here is that each of the elements of the pipe is simply a
function, and could be a nested pipeline. For example, we could create an
authenticated pipeline by embedding the browser pipeline:
authenticated_pipeline = &> browser_pipeline.() |> authenticate
How?
If we created a new prefix operator in the interpreter, then we could
implement a proof of concept as a library. Folks could then use this for a
while to see if the idea has merit, and if so, possibly roll this into the
language syntax.
I’d be happy to do this if there’s interest.
Dave
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