[Haskell-cafe] How can I use ghci more wisely?

[Jun Inoue]

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 <zhiwudazhanjiangshi at 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
>
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-- 
Jun Inoue