Re: Can I check if a value is convertible to a valid value of an enum?

[Meta via Digitalmars-d-learn]

On Friday, 25 September 2015 at 03:20:24 UTC, Nicholas Wilson 
wrote:

find + EnumMembers should do the trick
if ( (EnumMembers!SomeType).canFind(value))
{
// ...
}


Should be

if (only(EnumMembers!SomeType).canFind(value))
{
//...
}

Re: Can I check if a value is convertible to a valid value of an enum?

[thedeemon via Digitalmars-d-learn]

On Friday, 25 September 2015 at 03:12:20 UTC, French Football 
wrote:

...without having to loop over the enum?
writeln( test( valid_value ) ); //prints true


Since `value` is known only at run time, some checks need to be 
performed at run time anyway. One way of doing it without 
iterating over all variants is to create a static hash table


bool[string] valid_strings;

and populate it in static constructor, then in your function you 
can just write


if (value in valid_strings) ...

Can I check if a value is convertible to a valid value of an enum?

[French Football via Digitalmars-d-learn]

...without having to loop over the enum?

enum SomeType : string { CHEESE = "cheese", POTATO = "potato" }
string valid_value = "cheese";
string invalid_value = "pizza";

bool test( string value ){
if( value.isConvertableToSomeType ){ // this be the magic I 
seek

//do something
return true;
}
return false;
}

void main(){
writeln( test( valid_value ) ); //prints true
writeln( test( invalid_value ) ); //prints false
}

Or would I need to foreach over the enum somehow?

Re: Can I check if a value is convertible to a valid value of an enum?

[Nicholas Wilson via Digitalmars-d-learn]

On Friday, 25 September 2015 at 03:12:20 UTC, French Football 
wrote:

...without having to loop over the enum?

enum SomeType : string { CHEESE = "cheese", POTATO = "potato" }
string valid_value = "cheese";
string invalid_value = "pizza";

bool test( string value ){
if( value.isConvertableToSomeType ){ // this be the magic I 
seek

//do something
return true;
}
return false;
}

void main(){
writeln( test( valid_value ) ); //prints true
writeln( test( invalid_value ) ); //prints false
}

Or would I need to foreach over the enum somehow?


find + EnumMembers should do the trick
if ( (EnumMembers!SomeType).canFind(value))
{
// ...
}