• Thomas Gregory (18/18) Jan 25 2019 I would like to check that a char (unknown at compile time)
• Paul Backus (10/28) Jan 25 2019 You can do this with AliasSeq and staticIndexOf:
• Murilo (4/22) Feb 05 2019 Join this group https://www.facebook.com/groups/662119670846705/

Thomas Gregory <charles.gregory940 topper.wku.edu> writes:

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.

Paul Backus <snarwin gmail.com> writes:

On Friday, 25 January 2019 at 15:53:10 UTC, Thomas Gregory wrote:
 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.

You can do this with AliasSeq and staticIndexOf:

import std.meta;

alias Types = AliasSeq!(byte, ubyte, short, ushort, int, uint);
enum typeIndex(T) = staticIndexOf!(T, Types);
char[6] typechars="cCsSiI";

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

Runnable version: https://run.dlang.io/is/Tps38K

Murilo <murilomiranda92 hotmail.com> writes:

On Friday, 25 January 2019 at 15:53:10 UTC, Thomas Gregory wrote:
 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.

Join this group https://www.facebook.com/groups/662119670846705/ 
, it is the D lang facebook group, there we can help you out with 
any doubts.