Assignments with pipelines are often a great indication that a function can
be refactored.
For instance, if you have a function like follows:
def myfun(x, y) do
a =
x
|> fun_1
|> fun_2
b =
y
|> fun_3
|> fun_4
# now do something with a and b, e.g.:
%myStruct{foo: a * b}
end
then this is a great indication that this function can be refactored to
something like:
def myfun(x, y) do
a = subfun(x)
b = subfun_b(y)
# now do something with a and b, e.g.:
%myStruct{foo: a * b}
end
defp subfun_a(x) do
x
|> fun_1
|> fun_2
end
defp subfun_b(y) do
y
|> fun_3
|> fun_4
end
I believe this is approach is at least as clean as this proposal, without
needing new syntax. :-)
On Monday, January 2, 2017 at 12:01:45 AM UTC+1, Filip Haglund wrote:
>
> I love the flow of how pipelines read top-down as a series of steps, but
> there's something I don't like about it; having to look back at the start
> of the pipeline again to see in what variable the result is stored. It's an
> uncanny valley; reading functional code top-down is really clear and easy,
> but having to jump back up every now and then feels like when developers
> extract single-use functions that really should've stayed inline. It's a
> readibility issue.
>
> I wish the assignment was at the end of the pipeline instead. Equality
> could've worked, but doesn't, since it handles left and right arguments
> differently (illegal pattern, otherwise it'd be great to just put the
> variable assignment at the end, `= b`).
>
> Here's a macro that kinda simulates how it would work.
>
> defmacro into(a, b) do
> {:=, [line: 1], [b, a]}
> end
>
> Intended demo-usage:
>
> |> (into b)
>
>
> I'd prefer something like `|=>` in place of a pipe
>
> a
> |> fn1
> |> fn2
> |=> b
>
> but this is just a macro right now.
>
>
> What do you think?
>
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