Re: WHEN and UNLESS, if you will (was: [ANN] Introducing Scala, step 1)

"Steven E. Harris" <seh@xxxxxxxxx> writes:
> From the comments,
> 
> ,----
> | note that 'if' returns a value
> `----
> 
> Has there been any discussion about augmenting "if" with its friends
> "when" and "unless"¹, as provided in Common Lisp? There,
> 
>   (when test-form consequent)
> 

These only really seems to pay off if you have multiple statements in
the consequent.  In Lisp, it is nice to write things like:

  (when test
    statement1
    statement2) 

If you wrote it with an if, it would be significantly longer:

  (if test
    (begin
      statement1
      statement2))


Scala just writes {} instead of (begin ), so the saving is not worth
it.


Incidentally, there is something analogous in Scala: cases in a
pattern match do not need to have braces around them multiple
statements.


  case Foo =>
    statement1
    statement2
    statement3

  case Bar =>
    statement4
    statement5



-Lex