On Sun, Mar 17, 2013 at 2:43 AM, Claus Reinke <[email protected]>wrote:
> Neither arguments.callee (not available in strict) nor let (clumsy to
> use in expressions) are needed for self-reference
>
> var rec = (f) => f((...args)=>rec(f)(...args));
>
> var f = (self)=>(n)=> n>1 ? n*self(n-1) : n;
>
> [1,2,3,4,5,6].map((n)=>rec(f)(**n));
>
...but then you have a function rec which self-references. Much better to
use the Z combinator:
f => (x => f(v => x(x)(v)))(x => f(v => x(x)(v)))
which can be conveniently inlined into any expression where it's used:
js> [1,2,3,4,5,6].map((n)=>(f => (x => f(v => x(x)(v)))(x => f(v =>
x(x)(v))))(self => n => n>1 ? n*self(n-1) : n)(n));
[1, 2, 6, 24, 120, 720]
Obviously this is much better than arguments.callee.
-j
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