LISP to Ruby translation

[Douglas Livingstone]

Jut a quick one, how do you translate this:

((if (zero? 0) + -) 3 4)
=3D> 7

to Ruby?

Cheers,
Douglas

 

[Joel VanderWerf]

Jut a quick one, how do you translate this:

((if (zero? 0) + -) 3 4)
=> 7

to Ruby?

Cheers,
Douglas

3.send(x.zero? ? :+ : :-, 4)

It's a little hard to read with all those colons. Maybe this is better:

3.send(if x.zero? then :+ else :- end, 4)

Or you could replace symbols with strings for readability, at a cost to
speed:

p 3.send(x.zero? ? "+" : "-", 4)

 

[Neil Stevens]

Jut a quick one, how do you translate this:

((if (zero? 0) + -) 3 4)
=> 7

to Ruby?

Well, these kind of questions are rarely helpful; translating an
idiomatic expression out of context from one language is often useless,
because in a greater context the ruby code might be doing something
completely different to begin with.

But, if you want a one-liner...

3.method(0.zero? ? :+ : .call(4)

 

[Edward Faulkner]

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=20
What dialect of LISP is that? Not Common... CL has no "zero?"

It's Scheme. A much nicer dialect than CL, IMHO. ;-)

I think in CL the equivalent would be:

((if (zerop 0) #'+ #'-) 3 4)

Note the ugly sharp-quotes, due to the fact that CL has separate
namespaces for values and functions.

regards,
Ed

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[Joel VanderWerf]

7 if true

--Steve

7

 

[Martin DeMello]

7

There - who says ruby isn't concise!

martin