On 9/23/14, 12:01 PM, H. S. Teoh via Digitalmars-d wrote:
On Tue, Sep 23, 2014 at 06:56:56PM +0000, Meta via Digitalmars-d wrote:
On Tuesday, 23 September 2014 at 18:52:13 UTC, H. S. Teoh via Digitalmars-d
wrote:
I can think of a few:
1) Change lookup rules so that symbols pulled in by local import are
found last. Walter has stated that he disagrees with this approach
because it complicates symbol lookup rules.
2) Emit a compile error if any symbol pulled in by the local import
shadows a symbol currently in scope, according to the same rules as
declaring local variables that shadow identically-named variables in
an outer scope within the current function body.
3) What you proposed in the bugnotes: only allow `static import xyz;`
and `import xyz : a, b, c;` at local scope.
As far as breakage of existing code is concerned, (1) and (2) will
only break code where there was already a problem (an outer scope's
symbol is being shadowed, most likely unintentionally, by the
import). (3) will likely cause backlash because it will break a LOT
of code that currently compiles and likely to have no actual
problems. Not to mention that while naming specific symbols to import
works for trivial cases, it can quickly and easily devolve into
inordinately long lists of symbols once the local scope grows into
non-trivial code. People are unlikely to be happy with this.
Which leads to this variation of (2):
2b) Allow unqualified `import xyz;` in local scope, but only if NONE
of the imported symbols shadows ANY symbol visible from that scope.
T
The only tenable option from that list seems to be 1. 2 and 2b either
compile or not depending on the implementation details of the module
(i.e., add a symbol i to a module and it may break code in an entirely
different module that imports your module), and 3 will break a lot of
valid code.
Good luck convincing Walter, then. :-( Or maybe if we can convince
Andrei to twist his arm hard enough... :-P
This is a gaping hole that gets worse by the minute. We must fix it with
the next release. -- Andrei
