[Swift-devel] 'mapped type' terminology

[Ben Clifford]

On Wed, 28 Jan 2009, Ian Foster wrote:

> The "dataset" construct is intended to refer to objects that have a
> representation both in memory and on disk. If we use DSHandle to refer to
> things that have no disk representation, that seems contrary to the way the
> construct was originally defined.

DSHandle is a specific java interface which is used to deal with data in 
SwiftScript which looks like data. Initially it did not include things 
like ints and other primitive data, but subsequent development has 
indicated that it is desirable for primitive data to be not so primitive 
(for example, being able to participate in data dependency ordering of job 
execution).

I'm more interested in clarifying what is mean by 'dataset' - whether it 
means 'any data in swiftscript' (which is what DSHandle means), or what 
subset of data it means.

No dataset in Swift has an in-memory representation of its value, though 
there is in-memory representation of 'managementy' things to do with that 
data (eg. where to find the data in URI-space, and how it is interacting 
with data-dependency ordering of job execution).

Some data (the extern type) has no mapped representation in URI-space, 
because the extern type pretty much explicitly says "Swift is having 
nothing to do with where you keep this data".

So the model is somewhat more complicated than the model that was floating 
around 3 years ago.

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