Thanks for the tip, David, I didn't know about that flag! Looks really handy for playing with EDSLs, which is usually better off displayed through Doc, but the default Show instance is indispensable when I find a bug in the conversion to the Doc.
Unfortunately, though, I'd be reluctant to make data-pprint the universal default as it is now. I forgot to mention this in my previous post, but data-pprint doesn't let you customize the output per-datatype. It just works generically over Data.Data instances and the format is fixed to be the same as default Show instances (except for lists, which are special-cased internally). So as annoying as the explicit pprint is, I see it as a necessary evil. Perhaps I can generalize its interface and send a patch. I have some ideas but never got around to trying them. On Wed, Jul 24, 2013 at 10:16 PM, David McBride <toa...@gmail.com> wrote: > You might like to know about this option for ghci -interactive-print > > I tested it with data-pprint though and it didn't work because it > returns an IO Doc instead of IO () (I assume). But if you wrote a > function that used that, returned the right type, cabal installed it > and put it in your .ghci, you would have your pprinting by default > whenever you use ghci. > > On Wed, Jul 24, 2013 at 7:33 AM, Jun Inoue <jun.lam...@gmail.com> wrote: >> The data-pprint package's pprint function might give you a quick fix. >> For example: >> >> Prelude> :m Data.PPrint >> Prelude Data.PPrint> pprint [1..] >> [1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, >> 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, >> 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, >> 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, >> 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, >> 88, 89, 90, 91, 92, 93, 94, 95, 96, 97, 98, 99, 100, 101, 102, 103, >> 104, 105, 106, 107, 108, 109, 110, 111, 112, 113, 114, 115, 116, >> 117, 118, 119, 120, 121, 122, 123, 124, 125, 126, 127, 128, 129, >> 130, 131, 132, 133, 134, 135, …, ……] >> Prelude Data.PPrint> let long_computation = long_computation >> Prelude Data.PPrint> pprint [1, long_computation, 3] >> [1, ⊥₁, 3] >> ⊥₁: timeout at 0% >> >> It's a bit of a hassle to have to type "pprint" all the time though, >> and it doesn't give you a way to show the data without printing to the >> terminal in the IO monad. >> >> On Wed, Jul 24, 2013 at 4:30 AM, yi lu <zhiwudazhanjiang...@gmail.com> wrote: >>> 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 >>> >>> _______________________________________________ >>> Haskell-Cafe mailing list >>> Haskell-Cafe@haskell.org >>> http://www.haskell.org/mailman/listinfo/haskell-cafe >>> >> >> >> >> -- >> Jun Inoue >> >> _______________________________________________ >> Haskell-Cafe mailing list >> Haskell-Cafe@haskell.org >> http://www.haskell.org/mailman/listinfo/haskell-cafe -- Jun Inoue _______________________________________________ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe