Bill Baxter wrote:
On Wed, Oct 7, 2009 at 11:21 AM, Don <nos...@nospam.com> wrote:
By contrast, something like Nemerle macros are a kludge. The idea of
providing a 'hook' into the compiler is a horrible hack. It exposes all
kinds of compiler internals. Yes, it has nicer syntax.
Are you talking specifically about the ability to define new syntax?
Because it looks to me that one can use nemerle macros just fine
without defining new syntax.
I'm getting that from here: http://nemerle.org/Macros_tutorial
Here's just a simple macro that adds no new syntax from that page:
macro m () {
Nemerle.IO.printf ("compile-time\n");
<[ Nemerle.IO.printf ("run-time\n") ]>;
}
module M {
public Main () : void {
m ();
}
}
That seems significantly more elegant to me than
string m() {
pragma(msg, "compile-time");
return q{writefln("run-time");}
}
void main() {
mixin(m());
}
So it looks to me like the mechanics of it are basically identical.
Just Nemerle's syntax is nicer.
Only with trivial examples. With more complicated examples they look
less identical. I'm basing my views on pages like this:
http://nemerle.org/Macros_-_extended_course._Part_2
Unless I'm totally misunderstanding this, it looks to me as though
Nemerle macros are implemented as compiler plugins.
All the advanced facilities are obtained by exposing the compiler's API!
I pesonally think that is an utterly revolting thing to add to a language.
Compare with macros in Lisp and Forth.
If you want to condem Nemerle's ability to define new syntax, I think
that should be taken up as a separate matter.
I do think it's a profoundly bad idea in a C-like language, but it's not
what I'm referring to here.
