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.
