digitalmars.D - enums extension
- Comrad (8/8) May 15 2012 Dear developers and community,
- Mehrdad (15/23) May 15 2012 Dunno... but the way I'd use them would be more like:
- Robert DaSilva (6/30) May 15 2012 The inheritances notation implies that it's a subset and can be
- Simen Kjaeraas (44/52) May 15 2012 I have implemented this functionality in user code, with some caveats:
- Comrad (3/58) May 17 2012 This is not really useful, because one can't pass Foo into a
Dear developers and community, I want to draw you attention to the topic which was already discussed here: http://forum.dlang.org/thread/9to6n8$12d6$1 digitaldaemon.com and here: http://forum.dlang.org/thread/bl1n0e$1km5$1 digitaldaemon.com My question is: was something similar already done? are there some plans to do that?
May 15 2012
On Wednesday, 16 May 2012 at 04:22:18 UTC, Comrad wrote:Dear developers and community, I want to draw you attention to the topic which was already discussed here: http://forum.dlang.org/thread/9to6n8$12d6$1 digitaldaemon.com and here: http://forum.dlang.org/thread/bl1n0e$1km5$1 digitaldaemon.com My question is: was something similar already done? are there some plans to do that?Dunno... but the way I'd use them would be more like: enum AccessMask { GENERIC_READ = 0x80000000, GENERIC_WRITE = 0x40000000, GENERIC_EXECUTE = 0x20000000, GENERIC_ALL = 0x10000000, //.... } enum FileAccessMask : AccessMask { FILE_READ_DATA = 0x0001, //... }
May 15 2012
On Wednesday, 16 May 2012 at 05:49:01 UTC, Mehrdad wrote:On Wednesday, 16 May 2012 at 04:22:18 UTC, Comrad wrote:The inheritances notation implies that it's a subset and can be assigned to an instances of the base. This would not be true with enums. FileAccessMask foo = FileAccessMask.FILE_READ_DATA; AccessMask bar = foo; // ErrorDear developers and community, I want to draw you attention to the topic which was already discussed here: http://forum.dlang.org/thread/9to6n8$12d6$1 digitaldaemon.com and here: http://forum.dlang.org/thread/bl1n0e$1km5$1 digitaldaemon.com My question is: was something similar already done? are there some plans to do that?Dunno... but the way I'd use them would be more like: enum AccessMask { GENERIC_READ = 0x80000000, GENERIC_WRITE = 0x40000000, GENERIC_EXECUTE = 0x20000000, GENERIC_ALL = 0x10000000, //.... } enum FileAccessMask : AccessMask { FILE_READ_DATA = 0x0001, //... }
May 15 2012
On Wednesday, 16 May 2012 at 06:24:54 UTC, Robert DaSilva wrote:The inheritances notation implies that it's a subset and can be assigned to an instances of the base. This would not be true with enums. FileAccessMask foo = FileAccessMask.FILE_READ_DATA; AccessMask bar = foo; // ErrorActually, that^ *should* work in my case; that was my point...
May 17 2012
"Mehrdad" <wfunction hotmail.com> On Thursday, 17 May 2012 at 18:27:07 UTC, Mehrdad wrote:On Wednesday, 16 May 2012 at 06:24:54 UTC, Robert DaSilva wrote:Wait, no, scratch that, I misread it; you're right. It shouldn't work without a cast, but it should work with a cast.The inheritances notation implies that it's a subset and can be assigned to an instances of the base. This would not be true with enums. FileAccessMask foo = FileAccessMask.FILE_READ_DATA; AccessMask bar = foo; // ErrorActually, that^ *should* work in my case; that was my point...
May 17 2012
On Wed, 16 May 2012 06:22:15 +0200, Comrad <comrad.karlovich googlemail.com> wrote:Dear developers and community, I want to draw you attention to the topic which was already discussed here: http://forum.dlang.org/thread/9to6n8$12d6$1 digitaldaemon.com and here: http://forum.dlang.org/thread/bl1n0e$1km5$1 digitaldaemon.com My question is: was something similar already done? are there some plans to do that?I have implemented this functionality in user code, with some caveats: module enumMagic; string EnumDefAsString(T)() if (is(T == enum)) { string result = ""; foreach (e; __traits(allMembers, T)) { result ~= e ~ " = T." ~ e ~ ","; } return result; } template ExtendEnum(T, string s) if (is(T == enum) && is(typeof({mixin("enum a{"~s~"}");}))) { mixin( "enum ExtendEnum {" ~ EnumDefAsString!T() ~ s ~ "}"); } unittest { enum Foo { a, b, c } alias ExtendEnum!( Foo, q{ d, e }) Bar; Bar b; b = Bar.a; // Look ma, I stole this from Foo! b = Bar.d; assert( Bar.a == Foo.a ); // Can compare the two. //b = Foo.a; // But cannot assign from one to the other. } void main( ) { } A library implementation with the missing features is possible, but would use a struct instead of an enum, an be a rather larger piece of code than this.
May 15 2012
On Wednesday, 16 May 2012 at 05:54:45 UTC, Simen Kjaeraas wrote:On Wed, 16 May 2012 06:22:15 +0200, Comrad <comrad.karlovich googlemail.com> wrote:This is not really useful, because one can't pass Foo into a function if it's declared to take Bar...Dear developers and community, I want to draw you attention to the topic which was already discussed here: http://forum.dlang.org/thread/9to6n8$12d6$1 digitaldaemon.com and here: http://forum.dlang.org/thread/bl1n0e$1km5$1 digitaldaemon.com My question is: was something similar already done? are there some plans to do that?I have implemented this functionality in user code, with some caveats: module enumMagic; string EnumDefAsString(T)() if (is(T == enum)) { string result = ""; foreach (e; __traits(allMembers, T)) { result ~= e ~ " = T." ~ e ~ ","; } return result; } template ExtendEnum(T, string s) if (is(T == enum) && is(typeof({mixin("enum a{"~s~"}");}))) { mixin( "enum ExtendEnum {" ~ EnumDefAsString!T() ~ s ~ "}"); } unittest { enum Foo { a, b, c } alias ExtendEnum!( Foo, q{ d, e }) Bar; Bar b; b = Bar.a; // Look ma, I stole this from Foo! b = Bar.d; assert( Bar.a == Foo.a ); // Can compare the two. //b = Foo.a; // But cannot assign from one to the other. } void main( ) { } A library implementation with the missing features is possible, but would use a struct instead of an enum, an be a rather larger piece of code than this.
May 17 2012