On 03/23/2012 12:33 AM, F i L wrote:
Timon Gehr wrote:
We have the macro keyword. I envision something like:
macro replaceAggregate(macro newAggregate, macro loop : foreach(x;
aggr){statements}, macro x, macro aggr, macro statements) {
foreach(x; newAggregate){statements}
}
void main(){
int[] a = [1,2,3];
int[] b = [2,3,4];
replaceAggregate(b, foreach(x;a){writeln(x);});
}
(The syntax looks horrible, but you get the idea: AST walking by
pattern matching)
This looks substantially more complicated than what I had in mind. I
think it's a great idea, but something that could be added after the
initial functionality was there.
macro until(macro condition, string str){
while(!condition){
mixin(str); // string and mixin not strictly necessary,
// maybe enable the feature on macro params too
}
}
void main(){
bool done = false;
int x;
until(done){
done = foo(x++);
}
}
This is just a very rough sketch though, we would need a much more
refined design. I think getting the symbol scoping right is most
important.
I'm a bit confused about what's actually going on here, but it certainly
looks interesting. What exactly is being passed to "string str" in the
macro?
The idea is that if you have something of the form:
identifier(arguments) {
body
}
It would get transformed into:
identifier(arguments, q{
body
});
