This portion of haskell-mode (haskell-interactive-mode-eval-pretty) is what
the UI for something like this could look like:
https://www.youtube.com/watch?v=pu9AGSOySlE
This isn't an answer to your question, though, because expanding subparts
of the output doesn't drive evaluation. It would be very cool, and quite
possible, to have a variant of the Show typeclass that had output with such
structured laziness.
Another non-answer is to take a look at using vaccum[0] and
vaccum-graphviz[1] together, to get an idea of the heap structure of
unforced values. I've made a gist demonstrating how to use these to
visualize the heap without forcing values[2]. This doesn't show any
concrete values (as that would require some serious voodoo), but does show
how the heap changes due to thunks being forced.
-Michael
[0] http://hackage.haskell.org/package/vacuum
[1] http://hackage.haskell.org/package/vacuum-graphviz
[2] https://gist.github.com/mgsloan/6068915
On Tue, Jul 23, 2013 at 7:30 PM, yi lu
I am wondering how can I ask ghci to show an infinite list wisely. When I type
*fst ([1..],[1..10])*
The result is what as you may guess
*1,2,3,4,...*(continues to show, cut now)
How could I may ghci show
*[1..]*
this wise way not the long long long list itself?
Yi
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