schema: introduce support for StringMapType

schema: introduce support for StringMapType

This makes it simpler to have map[string]interface{}.

https://code.launchpad.net/~niemeyer/juju/go-better-schema/+merge/106045

(do not edit description out of merge proposal)

[niemeyer, 2012-05-16 19:09:40]

Please take a look.

[dave_cheney.net, 2012-05-16 23:35:44]

I like it, good job in tightening up the specification for the map keys.

https://codereview.appspot.com/6212054/diff/1/schema/schema.go
File schema/schema.go (right):

https://codereview.appspot.com/6212054/diff/1/schema/schema.go#newcode11
schema/schema.go:11: type (
nit: you removed the comments, maybe add them back if you feel they add value.

https://codereview.appspot.com/6212054/diff/1/schema/schema.go#newcode376
schema/schema.go:376: // The coerced output value has type schema.StringMapType.
It feels wrong that you have to annotate the concrete type of the interface
being returned from this function (and others).

[fwereade, 2012-05-17 09:27:47]

LGTM

https://codereview.appspot.com/6212054/diff/1/charm/meta.go
File charm/meta.go (left):

https://codereview.appspot.com/6212054/diff/1/charm/meta.go#oldcode197
charm/meta.go:197: "revision":    schema.Int(), // Obsolete
Not directly related... but do we need to continue to saddle ourselves with this
field? It was deprecated a good long time ago IIRC...

https://codereview.appspot.com/6212054/diff/1/schema/schema.go
File schema/schema.go (right):

https://codereview.appspot.com/6212054/diff/1/schema/schema.go#newcode376
schema/schema.go:376: // The coerced output value has type schema.StringMapType.
On 2012/05/16 23:35:45, dfc wrote:
> It feels wrong that you have to annotate the concrete type of the interface
> being returned from this function (and others).

I'm not sure about that -- I think it's useful information from a human POV.

[niemeyer, 2012-06-06 13:33:29]

This turned out to not be necessary for the improvements in the environment
configuration. I'll hold it off for the moment.