Invoke a method using a tuple as the parameter list

Question

I wonder what is the best way to do this.

val foo = Some("a")
val bar = Some(2)

def baz(a: String, b: Int) = if((b % 2) == 0) Some(a+","+b) else None

(x zip y) flatMap baz //does not compile of course
(x zip y) flatMap { x => baz(x._1, x._2) } //ugly

I would presume that Odersky et al. have another trick up theirs sleeve to reduce the noise in this example.

So the question is how to fight the clutter here assuming you are not allowed to change the implementation of baz (e.g. def baz(a: (String Int))).

+1 I know it is kind of a duplicate, but imho the title is way better so it will be found by more people :) — fresskoma, Jun 12 '11 at 16:35

score 19 · Accepted Answer · edited May 23 '17 at 11:45

19

This question has already been answered here: scala tuple unpacking

First, make foo to a function by partial application, then call tupled with your parameter list:

(foo _).tupled(myTuple)

edited May 23 '17 at 11:45

Community

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answered Jun 12 '11 at 15:20

notan3xit

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Thanks! (x zip y) flatMap (baz _).tupled works like a charm. – Joa Ebert Jun 12 '11 at 15:22

score 1 · Answer 2 · answered Jun 12 '11 at 15:43

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The most common way to cleanly unpack anything is with patterns or for-comprehensions:

for ((a,b) <- (x zip y); c <- baz(a,b)) yield(c)

answered Jun 12 '11 at 15:43

Andrew McGuinness

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Invoke a method using a tuple as the parameter list

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