http://www.paulgraham.com/accgen.html: "The problem: Write a function foo that takes a number n and returns a function that takes a number i, and returns n incremented by i." Lang contest after the author's book excerpt (Revenge of the Nerds, http://www.paulgraham.com/icad.html). No groovy yet. incze
Incze Lajos schrieb: > http://www.paulgraham.com/accgen.html: > > "The problem: Write a function foo that takes a number n > and returns a function that takes a number i, and returns > n incremented by i." def foo(n) { {i->n+i} } i and n can be of type Number if needed. > Lang contest after the author's book excerpt (Revenge of > the Nerds, http://www.paulgraham.com/icad.html). No groovy > yet. the goal is to show how different language try to simulate Lisp ;) bye blackdrag
Jochen Theodorou schrieb: > Incze Lajos schrieb: > >> http://www.paulgraham.com/accgen.html: >> >> "The problem: Write a function foo that takes a number n >> and returns a function that takes a number i, and returns >> n incremented by i." > > > def foo(n) { > {i->n+i} > } made a mistake here, the above returns n plus i, not n incremented by i. So the version is: def foo(n) { {i->n+=i} } examples in other languages can be found here: http://www.paulgraham.com/accgen.html bye blackdrag
I also came up with
def foo(n){
{i-> n+=i}
}
...but I thought I'd explain the process a bit, just
to expose the magic of syntax sugar in groovy...
The Java example was
----
public static Inttoint foo(final int n) {
return new Inttoint() {
int s = n;
public int call(int i) {
s = s + i;
return s;
}
};
}
----
refactorings into groovy
i) This rather verbose code is returning an Inttoint object,
which has one method call(int i), this callback is a perfect
candidate for replacement with Closure as the return type.
ii) The intermediate instance variable s is not needed in
groovy as with true closures the variable n will be lexically
bound, so we can refer to n directly in the method body of call(int i){...
(Continue reading)
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