Converting a type to a char

[Thomas Gregory via Digitalmars-d-learn]

I would like to check that a char (unknown at compile time) 
matches a particular type but I would like to do so without if 
statements or a hash map as I would like it to be as fast as 
possible.

Ideally I would choose something like this:
enum typeIndex{
byte = 0,
ubyte,
short,
ushort,
int,
uint
}

char[6] typechars="cCsSiI";

bool check(T)(char c){
   return typechars[typeIndex(typeof(T))]==c;
}

Though I know this is implementation is not remotely correct D.