[q-lang-users] The implicit operator in Q

[John C. <co...@cc...>]

Today I discovered that (whether intentionally or not, I don't know)
the Q rule processor will accept rules whose head is a variable.  You can
write rules like:

	X:Num Y:Num = X * Y;
	X:String Y:String = X ++ Y;
	X:List Y:List = X ++ Y;

and get these results:

==> 5 6
30

==> "abc" "def"
"abcdef"

==> [1,2,3] [4,5,6]
[1,2,3,4,5,6]

In effect, Q is allowing an implicit (empty) operator in these cases.
As long as the definition is associative, we also get useful results
from curried invocations like:

==> 1 2 3 4 5
120

This could be a very handy feature when dealing with types that have
some natural "principal" function of two or more arguments.

-- 
Said Agatha Christie / To E. Philips Oppenheim  John Cowan
"Who is this Hemingway? / Who is this Proust?   co...@cc...
Who is this Vladimir / Whatchamacallum,         http://www.ccil.org/~cowan
This neopostrealist / Rabble?" she groused.
        --author unknown to me; any suggestions?