Hi,

    I am working through the book 'Programming in D' and wanted to take the sample program on http://ddili.org/ders/d.en/types.html, one step further:


    import std.stdio;

    void main() {
        writeln("Type           : ", int.stringof);
        writeln("Length in bytes: ", int.sizeof);
        writeln("Minimum value  : ", int.min);
        writeln("Maximum value  : ", int.max);
        writeln("Initial value  : ", int.init);
    }

Say, I want to have a list of types and sniff each type as I go: (this doesn't compile, yet)




    auto types = [bool, byte, ubyte, short, ushort, int, uint, long, ulong, float, double, real, char, wchar, dchar];

    for (t; types) {
        sniffType(t);
    }


    void sniffType(auto myType) {
        writeln('Type           : ', myType.stringof);
        writeln('Length in bytes: ', myType.sizeof);
        writeln('Minimum value  : ', myType.min);
        writeln('Maximum value  : ', myType.max);
        writeln('Initial value  : ', myType.init);wri
    }


How would I go about achieving this?

PS: Thanks for making this book online, Ali!

On Saturday, 16 May 2020 at 05:22:49 UTC, n0den1te wrote:
> [...]

For example, like this:

´´´
import std;

alias types = AliasSeq!(
    bool, byte, ubyte, short, ushort, int, uint, long, ulong, float, double, real, char, wchar, dchar
);

void main()
{
	static foreach(type; types)
    {
        sniffType!type;
    }
}


void sniffType(T)() {
    writeln("Type           : ", T.stringof);
    writeln("Length in bytes: ", T.sizeof);
    static if(__traits(compiles, T.min))
        writeln("Minimum value  : ", T.min);
    writeln("Maximum value  : ", T.max);
    writeln("Initial value  : ", T.init);
}

´´´

However, for the char, wchar and dchar types the results of min, max and init are somewhat cumbersome. And T.min does not compile for the floating point types.

On 5/15/20 11:12 PM, Alex wrote:

>      static if(__traits(compiles, T.min))
>          writeln("Minimum value  : ", T.min);

A little improvement:

    static if(__traits(isFloating, T)) {
      writeln("Minimum value  : ", -T.max);

    } else {
      writeln("Minimum value  : ", T.min);
    }

Ali