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digitalmars.D.learn - How do I get the value cache()?

reply Marc <jckj33 gmail.com> writes:
let's assume I have

 class C {
   static string foo() { writeln("got called!"); //.... }
 }
then I want to cache foo at some point:
 import std.algorithm;
 auto v = cache(c.foo);
I call do:
 for(int i = 0; i <10; i++) {
 writeln(v);
 }
then it'll print "got called" only once, which is what I want but something obvious is how do I get the returned value as a string? here's why I'm confused more often than I should: I geeeting to D's way to do thing and the auto keyword even in documentation confused me a bit as I'm used to C++/C# world where the struct/class returned is explicity so I just navigate to aggregate type's documentation page.
Jan 14
parent Adam D. Ruppe <destructionator gmail.com> writes:
On Monday, 15 January 2018 at 02:54:16 UTC, Marc wrote:
 let's assume I have

 class C {
   static string foo() { writeln("got called!"); //.... }
 }
then I want to cache foo at some point:
 import std.algorithm;
 auto v = cache(c.foo);
That doesn't do what I think you think it does. http://dpldocs.info/experimental-docs/std.algorithm.iteration.cache.html Notice it is from the `iteration` module.. the cache function caches results of an iteration, not results of a function. It actually returns an object that caches the individual characters of that string, rather than the string! The memoize function is closer to what you want: http://dpldocs.info/experimental-docs/std.functional.memoize.2.html Though tbh, I think you should just simply do: string s = c.foo; // go ahead and just use s now
 here's why I'm confused more often than I should: I geeeting to 
 D's way to do thing and the auto keyword even in documentation 
 confused me a bit as I'm used to C++/C# world where the 
 struct/class returned is explicity so I just navigate to 
 aggregate type's documentation page.
The tricky thing is a lot of them create a new type based on its arguments, so there would be nothing to navigate to - it all depends on what you pass it. Though, you'll notice with memoize, it returns `ReturnType!fun`, that is, the same return type fun (which you passed to it) had.
Jan 14