I opened a radar a while ago about improving the import syntax in Swift and
haven’t received much of a response, so I’ll try to expand on my thoughts in
there here.
I’ve always been in love with the way Agda does Modules and imports. The
syntax is wonderfully natural, and the features it provides are surprisingly
useful given their simplicity. Because Swift forbids the redeclaration of
names between structs, enums, classes, and typealiases, I don’t believe that
the existing qualified import syntax is needed. Therefore, I propose the
introduction of 3 agda-esque operations for imports to replace the usual
`import {func|typealias|struct|class|enum|etc.}` syntax:
• import Foo using (bar, Baz, qux, corge, …)
• import Foo hiding (bar, baz, qux, corge, …)
• import Foo renaming (grault to garply, waldo to fred, …)
The first of these is used to introduce a limited set of identifiers into
scope, the second to import all but the given identifiers, and the third to
rename identifiers at the module level. Again, it should be obvious by
uniqueness of identifiers what each one is referencing, so qualification of
each identifier is unnecessary. If more context is needed, or more
granularity, a Haskell-esque
import Foo {using|hiding|renaming} (Baz(..) [to Graft(..)])
could be in order for structs, classes, and enums, but I don’t anticipate it
will be of much use because individual members are already qualified by their
containing structure or instance variable anyway.
What do you think?
~Robert Widmann
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