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digitalmars.D.learn - Why are enums with base type string not considered strings?

reply wolframw <wolframw protonmail.com> writes:
enum BoolEnum   : bool   { TestBool   = false }
enum CharEnum   : char   { TestChar   = 'A' }
enum StringEnum : string { TestString = "Hello" }

pragma(msg, isBoolean!BoolEnum);       // true
pragma(msg, isSomeChar!CharEnum);      // true
pragma(msg, isSomeString!StringEnum);  // false

Why does isSomeString not return true for an enum with base type 
string while
other isX functions return true for enums with an according base 
type X?
Regarding whether enums should be considered by these functions, 
I can see the
case being made one of both ways (personally, I'd say they 
should), but in the
example above it seems that different rules are applied.
Mar 14
parent reply Imperatorn <johan_forsberg_86 hotmail.com> writes:
On Sunday, 14 March 2021 at 10:42:17 UTC, wolframw wrote:
 enum BoolEnum   : bool   { TestBool   = false }
 enum CharEnum   : char   { TestChar   = 'A' }
 enum StringEnum : string { TestString = "Hello" }

 pragma(msg, isBoolean!BoolEnum);       // true
 pragma(msg, isSomeChar!CharEnum);      // true
 pragma(msg, isSomeString!StringEnum);  // false

 Why does isSomeString not return true for an enum with base 
 type string while
 other isX functions return true for enums with an according 
 base type X?
 Regarding whether enums should be considered by these 
 functions, I can see the
 case being made one of both ways (personally, I'd say they 
 should), but in the
 example above it seems that different rules are applied.
May be a regression? https://issues.dlang.org/show_bug.cgi?id=16573
Mar 14
parent reply Bastiaan Veelo <Bastiaan Veelo.net> writes:
On Sunday, 14 March 2021 at 16:09:39 UTC, Imperatorn wrote:
 On Sunday, 14 March 2021 at 10:42:17 UTC, wolframw wrote:
 enum BoolEnum   : bool   { TestBool   = false }
 enum CharEnum   : char   { TestChar   = 'A' }
 enum StringEnum : string { TestString = "Hello" }

 pragma(msg, isBoolean!BoolEnum);       // true
 pragma(msg, isSomeChar!CharEnum);      // true
 pragma(msg, isSomeString!StringEnum);  // false

 Why does isSomeString not return true for an enum with base 
 type string
May be a regression? https://issues.dlang.org/show_bug.cgi?id=16573
Indeed: https://run.dlang.io/is/liSDBZ It regressed in 2.079.1. Seems to be worth an issue report. —Bastiaan.
Mar 14
parent wolframw <wolframw protonmail.com> writes:
On Sunday, 14 March 2021 at 16:30:47 UTC, Bastiaan Veelo wrote:
 On Sunday, 14 March 2021 at 16:09:39 UTC, Imperatorn wrote:
 On Sunday, 14 March 2021 at 10:42:17 UTC, wolframw wrote:
 [...]
May be a regression? https://issues.dlang.org/show_bug.cgi?id=16573
Indeed: https://run.dlang.io/is/liSDBZ It regressed in 2.079.1. Seems to be worth an issue report. —Bastiaan.
Thanks for the advice. I've since had a deeper look into this located the PR that changed this behavior [1]. It seems this change was very much deliberate. In the PR, Jonathan also makes some points that are very hard to disagree with. So, perhaps the better solution would be to make isBoolean and isSomeChar (and perhaps other functions that I didn't think of) return false for enums? As a side note, isSomeChar returning true for enums is also what causes the behavior demonstrated in Issue 21639 [2]. [1] https://github.com/dlang/phobos/pull/5291 [2] https://issues.dlang.org/show_bug.cgi?id=21639
Mar 16