[Haskell-cafe] ANN: filestore 0.1

[Gwern Branwen]

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On Mon, Jan 26, 2009 at 5:35 AM, Thomas Davie  wrote:
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>
> On 26 Jan 2009, at 06:17, carmen wrote:
>
>> back to the original topic of the thread..
>>
>> cool project,
>>
>> id be interested ina pure-FS backend as well,
>
> Indeed, very cool!
>
> Can I make another feature request – generalize how diffs are created, so
> that I could in theory parse the file contents, and then diff the CSTs
> rather than diffing text.
>
> Bob_______________________________________________

Well, if you look you see that 'diff' is in the Generic module; that
is, diff can be defined using the basic operators provided by the
backend. In this case, you 'diff' two versions by retrieving a
specific revision, storing it, and then retrieving the other specific
revision, storing it, and then filestore calls the Diff package on the
two Strings.

Nothing stops you from copying this approach and adding in a parsing
step and then passing it to a custom diff - as long as the backend
supplies 'retrieve', you're good.

-- 
gwern