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0 pointsXcelerate10y ago0 comments

> I'd like an infix function composition operator.

Do you mean like the pipe symbol?

    rand() |> println

Or are you referring to something else?

0 comments

PeCaN10y ago

No, x |> f is equivalent to f(x) while (f ∘ g)(x) is equivalent to g(f(x)). Specifically, x |> f results in a value (of the type of the return value of f) while f ∘ g results always results in a function.

g0wda10y ago

Why not make one for yourself? ;)

julia> (∘)(f, g) = x -> f(g(x))

∘ (generic function with 1 method)

julia> (sum ∘ rand)(10)

3.397728240035534

Tip: type \circ<tab> to get ∘

PeCaN10y ago

I know, but why isn't something like this in core? * did function composition a while ago, but it was removed (beats me why) and hasn't been replaced.

Enough Perl6 has left me with <compose>(.) to get ∘ :-)

1 more reply

Tarrosion10y ago

That's exactly it - thanks! Somehow I missed that when searching the docs for "chain", "pipe", and "compose".

j / k navigate · click thread line to collapse

0 pointsXcelerate10y ago0 comments

> I'd like an infix function composition operator.

Do you mean like the pipe symbol?

    rand() |> println

Or are you referring to something else?

0 comments

PeCaN10y ago

g0wda10y ago

Why not make one for yourself? ;)

julia> (∘)(f, g) = x -> f(g(x))

∘ (generic function with 1 method)

julia> (sum ∘ rand)(10)

3.397728240035534

Tip: type \circ<tab> to get ∘

PeCaN10y ago

I know, but why isn't something like this in core? * did function composition a while ago, but it was removed (beats me why) and hasn't been replaced.

Enough Perl6 has left me with <compose>(.) to get ∘ :-)

1 more reply

Tarrosion10y ago

That's exactly it - thanks! Somehow I missed that when searching the docs for "chain", "pipe", and "compose".

j / k navigate · click thread line to collapse