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| Subject | Re: yield, C# etc | |||||||||||||||||||||
| From | Denis Koroskin <2korden@gmail.com> | |||||||||||||||||||||
| Date | Wed, 13 Aug 2008 16:12:54 +0400 | |||||||||||||||||||||
| Newsgroups | digitalmars.D | |||||||||||||||||||||
On Wed, 13 Aug 2008 15:49:58 +0400, bearophile <bearophileHUGS@lycos.com> wrote: > In normal D: > > struct A006068b { > int opApply(int delegate(ref int) dg) { > int result, aux; > aux = 0; result = dg(aux); if (result) return result; > foreach(x; A006068b()) { > if (x & 1) { > aux = 2 * x + 1; result = dg(aux); if (result) break; > aux = 2 * x; result = dg(aux); if (result) break; > } else { > if (x) > { aux = 2 * x; result = dg(aux); if (result) break; } > aux = 2 * x + 1; result = dg(aux); if (result) break; > } > } > return result; > } > } > > The D version is bad to read and bad to write, there's too much noise. > > Bye, > bearophile template yield(char[] value) { const char[] yield = "{ int aux = " ~ value ~ "; int res = dg(aux); if (res) { return res; } }"; } struct A006068b { int opApply(int delegate(ref int) dg) { mixin(yield!("0")); foreach(int x; A006068b()) { if (x & 1) { mixin(yield!("2 * x + 1")); mixin(yield!("2 * x")); } else { if (x) { mixin(yield!("2 * x")); } mixin(yield!("2 * x + 1")); } } return 0; } } I hope we will be able to write yield(2*x + 1); instead of mixin soon (as an AST macros or a built-in feature). | ||||||||||||||||||||||
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