[EMAIL PROTECTED] wrote:
Albert Y. C. Lai wrote:
If and only if the database is a purely functional immutable data
structure, this can be done. [...]
Many interesting databases are not purely functional immutable; most
reside in the external world and can spontaneously change behind your
program's back.
I don't think this is the problem because SQL requests are emitted
atomically anyway. The (Query a) monad here has nothing to do with
mutability of the data base.
The same clock read twice, each reading atomic, can give two different
results. (Cf. the monadic type signature of
Data.Time.Clock.getCurrentTime.)
The same SELECT to the same database issued twice, each time atomic, can
give two different results.
These are not referentially transparent. These are not purely functional.
The notation is a beauty bonus.
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