Am Freitag, 3. Mai 2013, 23:13:31 schrieb David A. Wheeler:
>  Another issue I see with the current leading $ behavior is this
> > inconsistency:
> >
> > foo (a b) ==> (foo (a b))
> > foo $ a b ==> (foo (a b))
> > (a b) ==> (a b)
> > $ a b ==> ((a b))  ; huh?!

The inconsistency is not in $, but in treating single-item lists specially:

a → a
a b → (a b)

Since (a b) is a single item, it gets treated as single item.

It makes the code more readable, but it also leads to some side-effects.

That’s one of the things I changed in wisp: To get the single-item behaviour, you have to prefix the item with a dot (.). The advantage is added consistency, but at the same time it is a trap: It’s easy to forget the . for a return value (real coding verified that assumption from Alan (I think it was Alan)).

Not adding brackets for a single item also has the advantage, that you can copy-paste lisp-code into readable. If you do the same in wisp, you have to prepend every top-level bracket with a dot.

Readable:

    (a b (c)) → (a b (c))

Wisp:

    . (a b (c)) → (a b (c))

On the other hand:

Readable:

    $ a b → ((a b))

Wisp:

    : a b → ((a b))
-or-
    (a b) → ((a b))

Best wishes,
Arne
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