André Thieme wrote:
> William James schrieb:
> > André Thieme wrote:
> >> William James schrieb:
> >>
> >>> def nif num, pos, zero, neg
> >>> send( num>0 ? pos : (num==0 ? zero : neg) )
> >>> end
> >> btw, your nif body is built out of 13 tokens, so more
> >> complicated than the Python version.
> >>
> >>
> >> André
> >> --
> >
> > def nif num, *args
> > send args[ 1 + (0 <=> num) ]
> > end
>
>
> send
> |
> |
> [ ]
> / \
> / \
> / \
> args +
> / \
> / \
> 1 ()
> |
> |
> <=>
> / \
> / \
> 0 num
>
> Okay, 9. Now it is at the complexity level of the Lisp
> and Python example.
> But how would a call to nif look like?
A call is unchanged:
[0, 2.5, -8].map{|x| nif x, :p, :z, :n}
> I hope it doesn't involve an extra operator to group the
> args into a list or tuple. That would add more complexity to
> each call - so one should better have a slightly more complex
> nif because that exists only one time.
>
> And can this nif now handle any input values, such as strings
> or function objects?
It handles only symbols.
I suppose this can handle anything ...
p = proc {
puts "very positive"
"positive" }
z = proc {
puts "no no"
"zero" }
n = proc {
puts "very negative"
"negative" }
def nif num, *args
args[ 1 + (0 <=> num) ].call
end
[0, 2.5, -8].map{|x| nif x, p, z, n}
puts [0, 2.5, -8].map{|x| nif x,
proc{'zero'}, proc{'plus'}, proc{'minus'}}
... if you wrap everything in a proc (lambda).
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