Here is a function that I wrote:
: ?sgn ( value negative-combinator zero-combinator positive-combinator -- )
roll ! -- neg zer pos value
dup 0 > [ drop 2nip call ] [
nip ! -- neg zer value
0 = [ nip ] [ drop ] if call
] if ;
My question is, why does the <=> function return the values: +lt+, +eq+ and
+gt+? Wouldn't it make more sense for it to return 1-, 0 and 1? This is what
the COMPARE function does in ANS-Forth. This results in a kind of
polymorphism because a function such as my ?sgn will work whether it follows
an integer subtraction or a call to COMPARE, or what not. In Factor I would
have to write another version of ?sgn specific to <=>. This is like how C
function names often have the type prefixed onto them, and there are
multiple versions of the same function for the various data types. That is
one of the many reasons why C is difficult to program in. Note that I'm not
criticizing Factor; I'm just trying to learn Factor's philosophy. I've long
noted many problems with ANS-Forth and have been looking for something
better --- which might be Factor.
One other quick question: Does Factor have something like the EXIT function
of ANS-Forth?
Also, I am translating a symbol-table program into Factor (originally
written in IBM370 assembly-language and later upgraded to ANS-Forth). How do
I go about making this available to the Factor community? This uses an
algorithm that I invented myself, which provides faster execution speed than
hash-tables IMHO.
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