How create new Scala Map class? -

in scala want create generic new map class called myclass. in class want maintain generality of types , modify method ++ sequence type. ++ method must merge equal object same key in map.

example

val map1 = ("a"->seq(1,2)) val map2 = ("a"->seq(2,3)) 

the result must

map1++map2 = ("a"->seq(1,2,3)) 

and not

map1++map2 = ("a"->seq(2,3)) 

for other type mymap must same of "classic" map class.

as others have pointed out in comments, should try first , come if encounter specific problem. here's how can start, given want implement map trait:

class myclass[a, +b] extends map[a, b] {    def get(key: a): option[b] = ???   def iterator: iterator[(a, b)] = ???   def +[b1 >: b](kv: scala.tuple2[a, b1]): map[a, b1] = ???   def -(key: a): map[a, b] = ???    override def ++[b1 >: b](xs: scala.collection.gentraversableonce[scala.tuple2[a, b1]]) = ???  } 

you can start existing map implementation, such as

class myclass[a, +b] extends scala.collection.immutable.hashmap[a, b] {    override def ++[b1 >: b](xs: scala.collection.gentraversableonce[scala.tuple2[a, b1]]) = ???  } 

however, in case compiler warn inheritance existing implementation unwise because of implementation details.