ContinuumIO/datashape — pull request #56 by mrocklin (2014-05-06 20:12:52+00:00)
Title: add subset_dshape

```Python
>>> print(subset_dshape(0, 'var * {name: string, amount: int32}'))
{ name : string, amount : int32 }

>>> print(subset_dshape('x', '{x: int, y: int}'))
int32

>>> print(subset_dshape((slice(0, 7, 2), 'amount'),
... 'var * {name: string, amount: int32}'))
3 * int32
```

Fixes https://github.com/ContinuumIO/datashape/issues/55

We need this logic somewhere. Datashape seems like a good place.

Possible controversial points:

1. Better name?
2. I'm still depending on doctests