On 08/25/2011 04:08 AM, bearophile wrote:
Timon Gehr:
It is especially compact in that program,
The coding style of that program is an unreadable mess, example:
LList!T hamming(T)(){
LList!T merge(LList!T xs, LList!T ys){
return lz({
auto x=xs.head, y=ys.head;
if(x()<y()) return cons(x,merge(xs.tail,ys))();
else if(x()>y()) return cons(y,merge(xs,ys.tail))();
else return cons(x,merge(xs.tail,ys.tail))();
});
}
return lz({
LList!T r;
r=cons(st(1),lz({return merge(merge(map((Lazy!T a){return
lz({return 2*a();});},r),map((Lazy!T a){return lz({return
3*a();});},r)),map((Lazy!T a){return lz({return 5*a();});},r))();}));
return r();
});
}
This is a bit better:
LList!T hamming(T)() {
static LList!T merge(LList!T xs, LList!T ys) {
return lz({
auto x = xs.head;
auto y = ys.head;
if (x()< y())
return cons(x, merge(xs.tail, ys))();
else if (x()> y())
return cons(y, merge(xs, ys.tail))();
else
return cons(x, merge(xs.tail, ys.tail))();
});
}
return lz({
LList!T r;
r = cons(st(BigInt(1)), lz({
return merge(merge(map((Lazy!T a){ return lz({ return 2 *
a(); }); }, r),
map((Lazy!T a){ return lz({ return 3 *
a(); }); }, r)),
map((Lazy!T a){ return lz({ return 5 * a();
}); }, r))();
}));
return r();
});
}
Well, the main reason it is an unreadable mess is the bug with lazy and
closures I reported, and I think inserting whitespace does not
necessarily make the code better readable. (I like especially the first
half of the code snippet better in the format I provided)
I usually do not spend much time to format my code, especially if like
here the end result is not significantly better readable. Maybe code
formatting should be automated completely via a dedicated tool.
I am starting to think this is not as intended.
I think it's a DMD bug. Fit for Bugzilla.
See http://d.puremagic.com/issues/show_bug.cgi?id=6552
I cannot seem to find it, but I'd like to vote on it. Do you have a link?
I have updated this:
http://d.puremagic.com/issues/show_bug.cgi?id=5970
Thanks.
