On 02/05/2013 08:28 AM, Jacob Carlborg wrote:
On 2013-02-05 01:15, Timon Gehr wrote:
IMO macros should be fully hygienic by default, with opt-out options.
That's the opposite of how the macros in Scala works.
As far as my understanding goes, quasi-quoting is hygienic, and manual
AST building provides both options.
It's quite easy to say if it should be hygienic or not. The hard part is
to figure out the details and how to break hygienicy, when there's need
for it.
We could provide all nested scopes in an array as part of the context.
macro foo(Context context){
return<[
context.scopes[0].x++;
context.scopes[1].x++;
]>;
}
int x = 2;
void main(){
int x=0;
foo();
assert(x==1 && .x==3);
}
If manual AST building is supported, it could additionally do something
along the following lines:
module macros;
int x=0;
macro foo(Context context){
return SequenceExp(
AssignExp(Symbol!x(), Constant(1)),
AssignExp(Identifier("x"), Constant(2)),
);
}
// ---
module m;
import macros;
int x=0;
void main(){
foo();
assert(macros.x==1 && x==2);
}
