Hello, World!

[H. S. Teoh]

On Wed, Mar 30, 2022 at 06:50:40PM +0000, Max Samukha via Digitalmars-d wrote:
> On Wednesday, 30 March 2022 at 15:49:08 UTC, H. S. Teoh wrote:
[...]
> > And pragma(msg) is technically not your program outputting the
> > message, but the compiler. You need to put it in main() for a proper
> > implementation of Hello World. ;-)
[...]
> template add(int x)
> {
>     pragma(msg, x);
>     int add(int y)
>     {
>         import std.stdio: writeln;
>         writeln(y);
>         return x + y;
>     }
> }
> 
> void main()
> {
>     auto z = add!1(2);
> }
> 
> Is this a program that starts at compile time and continues at run
> time, or a meta-program that generates another program? )
[...]

It's a program with a split personality that prints half its output at
compile time and the other half at runtime. :-D

If you only compile but never run it, then you only get half of its
output, and if you run it multiple times you get redundant output. :-P


T

-- 
The two rules of success: 1. Don't tell everything you know. -- YHL