🚀 go-pugleaf

mtm4@rsvl.unisys.com (Michael McCormick) writes:

>"W. Dicks" <wd@isis.co.za> shared the following on 13 Mar 96 07:31:13 GMT:
>
>>The system that I'm working often needs to know the string 
>>value of an enum. [...] Is it not possible that such 
>>a functionality can be built into enums?
>
>What you are essentially asking for is language support for converting
>a label into a string respresentation of its name.  That is a very
>unusual feature to find in any language, since it would require the
>compiler to place the symbolic dictionary in the executable file. 
>I don't think there's a snowball's chance of this getting into C++.

I wouldn't call it "very unusual" -- there are many existing languages
which have similar features, including Haskell, Prolog, and Java -- not
to mention C++ itself!  If `x' is a polymorphic class variable, then
the C++ expression `typeid(x).name()' returns a string representation
of the class name.

>Since enum is by definition an integral type, why not assign values to your
>enumerators that can be used as indexes into a string?:
>
> enum week {MON=0,TUE=4,WED=8,THU=12,FRI=16,SAT=20,SUN=24};
> const char * days = "MON\0TUE\0WED\0THU\0FRI\0SAT\0SUN";
>
> char const * weekImage(week day) = days[day];

I think a much cleaner workaround would be to use an array of strings:

enum week {MON, TUE, WED, THU, FRI, SAT, SUN};
const char * days[] = { "MON", "TUE", "WED", "THU", "FRI", "SAT", "SUN" };
char const * weekImage(week day) { return days[day]; }

--
Fergus Henderson             	WWW: http://www.cs.mu.oz.au/~fjh
fjh@cs.mu.oz.au              	PGP: finger fjh@128.250.37.3
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