Re:Scala Feels like EJB 2
by pivo on Tuesday November 22, 2011 @03:59PM
(#3267336)
The :: is Scala's cons operator, the Nil means end-of-list. It's actually much more common in Scala to create a list like so:
This creates the same list that the example using :: did. It doesn't need to be explicitly terminated with Nil.
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What does cons operator mean? Concatenation? Constructor? Other than hello world I haven't done much Scala.
Cons is short for construct and comes from Lisp which has weird names for things; things like car and cdr.
It means construct a new list.
A cons A (or A :: B) means create a new list with A before B, where B can be a list item or a list itself and A is a list item.
The :: operator is right associative so "Jim" :: "Bob" :: Nil actually works like ("Jim" :: ("Bob" :: Nil) ) (Actually all operators that end in : are right associative in Scala.)
For more see: http://en.wikipedia.org/wiki/Cons