Scala delegate within multi-argument method call -

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assume there functional delegate method called "delegatedfoo()" needs passed argument method (ie, scala's version of function pointer) so:

addmydelegatedmethod(delegatedfoo)

assume (for brevity), line compiles/executes fine. change this:

addmydelegateoverridemethod("uh-o", delegatedfoo)

this line throw compiler exception: missing arguments method delegatedfoo in class myclass

q: how 1 go passing delegate (reference) within multi-argument method call? (is can done in scala?)

edit: more precise, signatures follows:

def delegatedfoo(str: string): string = { return "ok" } def addmydelegatedmethod(delegate: (string) => (string)) def addmydelegateoverridemethod(foo: string, delegate: (string) => (string))

update: after reviewing paolo's answer , doing more experimenting, best can tell issue (bug?) surfaces when there overloaded signature involved. (i didn't bother throwing example above, wasn't used -- having there appears give compiler headache):

scala> object mycontrol {    def dodele(stra: string, strb: string, delegate: string => string) { delegate(stra) }    def dodele(stra: string, count: int, delegate: string => string) { delegate(stra) } } defined module mycontrol  scala> def myfn(s: string): string = { println(s); s } myfn: (s: string)string  scala> mycontrol.dodele("hello", "bye", myfn) <console>:10: error: missing arguments method myfn; follow method `_' if want treat partially applied function           mycontrol.dodele("hello", "bye", myfn)

mycontrol has set of overloaded methods defined...comment out overload method (or change name) , compiler handle fine... :\

update:

as error says need explicitly follow myfn _

scala> mycontrol.dodele("hello", "bye", myfn _) hello

the reason in scala method (what define def , lives in class or object) not function (which more object apply method of own). in cases can pass method function required , scala "transform" 1 other you. in general, though, have follow method _ tell scala treat function.

note this, instance, in repl after definitions:

scala> myfn <console>:9: error: missing arguments method myfn; follow method `_' if want treat partially applied funct ion               myfn               ^  scala> myfn _ res4: string => string = <function1>

__

maybe should provide more complete example of you're trying do/what fails, works fine in scala:

scala> def delegatedfoo(str: string): string = "ok" delegatedfoo: (str: string)string  scala> def addmydelegatedmethod(delegate: string => string) = delegate("meh") addmydelegatedmethod: (delegate: string => string)string  scala> def addmydelegateoverridemethod(foo: string, delegate: string => string) = delegate(foo) addmydelegateoverridemethod: (foo: string, delegate: string => string)string  scala> addmydelegatedmethod(delegatedfoo) res0: string = ok  scala> addmydelegateoverridemethod("hey",delegatedfoo) res4: string = ok

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