Comments on while(nan): Fakin' closures

I used a mixin-expression and a ctfe-function to g...

2008-04-08T21:55:00.000+10:00

I used a mixin-expression and a ctfe-function to generate something along the lines of:

string var1 = "i am the context";
int var2 = 5;

&( ((new class Object {
this(string var1, int var2) { /* ... */ }
void run() {
/* closure body pasted here */
}
})(var1, var2) ).run );

which is also really safe but very complicated to implement and not that easy to use because you have to write the function body inside a string and have to explicitely select the variables you want to "import".

-- asmanian

I'm affraid it doesn't work at all.With compiler v...

2007-11-29T09:26:00.000+11:00

I'm affraid it doesn't work at all.

With compiler v1.010, it would work as intended in debug mode but not in release, giving 15, 42, 165. As for v1.024, both debug and release give 15, 42, 165.

Cool; that approach is probably a lot safer than m...

2007-08-29T01:28:00.000+10:00

Cool; that approach is probably a lot safer than mine is.

To be honest, I'd be much happier if delegates grew some kind of .dup method, but there you go.

Here's how you would do something similar using th...

2007-08-29T01:27:00.000+10:00

Here's how you would do something similar using the Tools package from scrapple:

xt4100 ~/d $ cat test2.d && echo "------" && gdc test2.d -o test2 scrapple/trunk/tools/tools/*.d -Iscrapple/trunk/tools && ./test2
module test2;
import std.stdio, tools.ext;
void delegate() make_dg(uint *target, uint what) {
return (ref uint *t, ref uint w) { *t=w; }~fix(target, what);
}

void main() {
uint f;
auto fn1=make_dg(&f, 42);
auto fn2=make_dg(&f, 1701);
f=15; writefln(f);
fn1(); writefln(f);
fn2(); writefln(f);
}
------
15
42
1701
The disadvantage is that you need to explicitly specify the external values you want to use. The advantage is that it stays away from the stack (or is that a disadvantage?)
std.bind works too, although I'd say that your trick has the advantage of being significantly neater. :)

--downs (who, coincidentally, wrote the tools package ^^)