On Wednesday, 14 December 2016 at 14:21:55 UTC, Andrei
Alexandrescu wrote:
On 12/14/16 8:26 AM, Dominikus Dittes Scherkl wrote:
On Tuesday, 13 December 2016 at 22:33:24 UTC, Andrei
Alexandrescu wrote:
Destroy.
https://github.com/dlang/DIPs/pull/51/files
Why not leave it as it is and only change the compiler to
perform inputs _within_ a function before evaluating the
declaration, so
that the symbols imported can be used in the declaration?
Thanks. I considered this but it put pressure on the
relationship between the name and where it's looked up.
Consider that imports in a function don't need to be at the
top. They may also be in nested scopes inside the function. It
becomes quite tenuous to explain where the parameter type names
are looked up. -- Andrei
Could restrict to imports that come before any other statements
in the function body, ie:
// valid, compiles when instantiated
void fun(Range)(Range r) if(isInputRange!Range) {
import std.range;
}
// invalid, import is not picked up because it is not the first
statement in the method body
void fun(Range)(Range r) if(isInputRange!Range) {
doThings();
import std.range;
}
If this is desirable, the error message for failed symbol lookup
of symbols in a function declaration should hint that imports in
the function body are only considered if they stand at the
beginning of the function, to help mitigate confusion.
Seems simple enough to specify and explain, honestly.
