Class-scoped typedefs

[DartBot]

This issue was originally filed by @seaneagan

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It should be possible to define typedefs at class scope. One big use case for this is typedefs which reference the immediately enclosing class, which may even be useful enough to warrant an implicit typedef, similar to python's class, but with a nicer name such as _Class or Class. This in combination with issue #47 would obviate the need to ever repeat a class's (possibly lengthy) name within it's body. To illustrate:

before: http://try.dartlang.org/s/EKkY
after: http://try.dartlang.org/s/kKkY

[DartBot]

This comment was originally written by @seaneagan

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Accidentally left a class name reference in the "after", should be: http://try.dartlang.org/s/QqUY

[DartBot]

This comment was originally written by [email protected]

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Added Area-Language, Triaged labels.

[DartBot]

This comment was originally written by [email protected]

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Note that typedefs are for function aliases, not classes or types in general.

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Removed Type-Defect label.
Added Type-Enhancement label.

[gbracha]

We will have typedefs for all types in the not-too-distant future. Whether we do local ones depends on a number of considerations.

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Set owner to @gbracha.

[DartBot]

This comment was originally written by [email protected]

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Sounds like this is already in the works, but I would recommend making sure this includes the generics.. As that supports a growing problem with Java -> Javascript mapping.. namely simple structured JSON documents:

typedef Map<String,Map<String,List<List<num>>>> MyJson;

[gbracha]

Yes, I expect we will support generics in typedefs

[DartBot]

This comment was originally written by @seaneagan

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In order to support generics in function alias typedefs, I think typedefs either need to be available in class/interface scope:

interface I<T> {
  typedef int f(T t);
  m(f closure);
}

or to make generic function alias typedefs reusable across interfaces/classes, generic methods would need to be added:

typedef int f<T>(T t);

interface I<T> {
  m(f<T> closure);
}

[anders-sandholm]

Added apr30-triage label.

[anders-sandholm]

Removed apr30-triage label.

[anders-sandholm]

Added triage1 label.

[anders-sandholm]

Removed triage1 label.
Added WontFix label.

[gbracha]

All types in Dart are top level which keeps things simple. This proposal is not consistent with that situation.