Can this not be done with the HList code? I am pretty sure you should be
able to
map projections over HLists of HLists... (although the HList generic map
is a bit
ugly, requiring instances of the Apply class).
Actually you should look in the OOHaskell paper (if you haven't already)
where it
discusses using "narrow" to allow homogeneous lists to be projected from
heterogeneous ones...
Keean.
John Meacham wrote:
another thing is that for any record syntax, we would want higher order
versions of the selection, setting, and updating routines. A quick
perusal of my source code shows over half my uses of record selectors
are in a higher order fashion. (which need to be generated with DrIFT
with the current syntax)
I mean something like
map (.foo) xs
to pull all the 'foo' fields out of xs. (using made up syntax)
or
map (foo_s 3) xs
to set all the foo fields to 3. (using DrIFT syntax)
John
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