CODEWITHSUNDEEP
scalascala-macrosparameterized-types
Daniel Macias
Daniel Macias

Reputation: 282

Scala Def Macros - How do I get the parameterized type member of a symbol?

I'm trying to get the parameterized type of a member on a symbol in a MACRO context. I only have a symbol available (can't use weakTypeOf[List[Blah]]) because I am iterating over a bunch of classes.

val meWantArg = classSymbol.member("paramList": TermName).typeSignature

returns... 

=> List[IWantThis]

How do I get IWantThis Type object???

I've tried:

meWantArg.typeSymbol.asType.typeParams //returns List(type A)

I've tried extraction:

TypeRef(_,_,args) = meWantArg //returns ()

Keep in mind, I am using the 2.10.2 macro plugin.

Upvotes: 2

Views: 275

Answers (1)

gourlaysama
gourlaysama

Reputation: 11290

I am guessing from => IWantThis that paramList is not a val but an arity-0 method without parentheses:

def paramList: List[IWantThis] = ???

If so, the member is a method type, and you have to get the return type of the method before extracting arguments from it:

val meWantArg = classSymbol.member("paramList": TermName).asMethod.returnType
val TypeRef(_,_,args) = meWantArg

Upvotes: 3

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