Re: Some strange behaviors of enums and string.startsWith

[Andre via Digitalmars-d-learn]

On Friday, 8 April 2016 at 14:56:51 UTC, Adam D. Ruppe wrote:

On Friday, 8 April 2016 at 14:38:10 UTC, Andre wrote:
Therefore I use std.conv.text to convert the string enum? to 
string.


That converts the *name* of the enum to string, not the 
contents. (BTW, I think the name of the enum is actually the 
more useful behavior.)


Use cast(string) if you want to get the content out.


Thanks a lot, now the behavior makes sense.
I will create a feature request for the phobos issue.

Kind regards
André

Re: Some strange behaviors of enums and string.startsWith

[Adam D. Ruppe via Digitalmars-d-learn]

On Friday, 8 April 2016 at 14:38:10 UTC, Andre wrote:
Therefore I use std.conv.text to convert the string enum? to 
string.


That converts the *name* of the enum to string, not the contents. 
(BTW, I think the name of the enum is actually the more useful 
behavior.)


Use cast(string) if you want to get the content out.



assert( ":abc".startsWith(CharEnum.a)); // OK
assert( ":abc".startsWith(ManifestConst)); // OK


makes sense


//assert( "abc".startsWith(StringEnum.a)); // Compiler error


I feel like that should work... Phobos is just being too picky on 
its types.


If you do cast(string) StringEnum.a, it is all good though.


assert( ":abc".startsWith(StringEnum.a.text)); // Assertion


StringEnum.a.text == "a" because .text (and to!string) returns 
the NAME of the enum, not its value. So ":" != "a" and it fails.



assert( "bc".startsWith(StringEnum.b.text)); // OK ???
}


StringEnum.b.text == "b" because the name coincidentally matches 
the value so it passes.

Some strange behaviors of enums and string.startsWith

[Andre via Digitalmars-d-learn]

Hi,

I have some issues with enums. Please have a look at the last 3 
assertions.
It is annoying that I cannot directly use my StringEnum for 
startsWith.
Therefore I use std.conv.text to convert the string enum? to 
string.
But then the assertion fails, that is very strange, it fails only 
for string ":" but

not for string "b".

Is this a bug? => Tested with DMD 2.071 on windows.

Kind regards
André

enum ManifestConst = ":";
enum CharEnum { a = ':' }
enum StringEnum{a = ":", b = "b"}

import std.string: startsWith, endsWith;
import std.conv: text;

void main()
{
assert( ":abc".startsWith(CharEnum.a)); // OK
assert( ":abc".startsWith(ManifestConst)); // OK
//assert( "abc".startsWith(StringEnum.a)); // Compiler error
	assert( ":abc".startsWith(StringEnum.a.text)); // Assertion 
failure

assert( "bc".startsWith(StringEnum.b.text)); // OK ???
}