Currying: How do I make the first login optional?
I am also studying the Scala
concept currying
. This is what I do
scala> def div(a:Int)(b:Int) = a/b
div: (a: Int)(b: Int)Int
scala> div(10)(2)
res9: Int = 5
scala> val d = div(10)_
d: Int => Int = <function1>
scala> d(5)
res10: Int = 2
scala> val e = div _ (2)
<console>:1: error: ';' expected but '(' found.
val e = div _ (2)
^
scala>
Question
- How can I make it a
both optional and not b
?
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1 answer
You can fix b
and get the function Int => Int
, but you need to keep the parentheses and unfortunately annotate the type:
scala> div(_: Int)(2)
res7: Int => Int = <function1>
scala> res7(10)
res8: Int = 5
scala> res7(2)
res9: Int = 1
a
is not "optional", just a parameter in the resulting function.
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