[Haskell-beginners] import question

[Bob Ippolito]

Like others said, you'll need to install the Decimal package in order to
use Data.Decimal.

If you really wanted to do it with a floating point type and no
dependencies you can use showFFloatAlt from Numeric to display with a
specified precision.

import Numeric
import Text.Show

main = putStrLn . showListWith (showFFloatAlt (Just 2)) [1.00, 1.01 ..
2.00] $ ""

On Wed, Feb 17, 2021 at 7:42 PM Galaxy Being <borgauf at gmail.com> wrote:

> As I've said, working at the ghci REPL,
>
> import Data.Decimal
> dList :: [Decimal]
> dList = [1.00,1.01..2.00]
> main = print dList
>
> errors out
>
> : <interactive>:76:11-17: error:
> :     Not in scope: type constructor or class `Decimal'
>
>
>
> On Wed, Feb 17, 2021 at 8:37 PM Bob Ippolito <bob at redivi.com> wrote:
>
>> You don't need to do any rounding if the list is already Decimal.
>>
>> If you wanted to format a Double with some specific decimal
>> representation you could look at Numeric.showFFloatAlt or similar.
>>
>> import Data.Decimal
>>
>> dList :: [Decimal]
>> dList = [1.00,1.01..2.00]
>>
>> main = print dList
>>
>>
>>
>> On Wed, Feb 17, 2021 at 5:27 PM Galaxy Being <borgauf at gmail.com> wrote:
>>
>>> I'm trying to create a list of real numbers with a two-decimal interval,
>>> a la
>>>
>>> > [1.0,1.01,1.02,...1.99,2.00]
>>>
>>> however, I get the float approximation problem
>>>
>>>
>>> [1.0,1.01,1.02,1.03,1.04,1.05,1.06,1.07,1.08,1.09,1.1,1.11,1.12,1.1300000000000001,1.1400000000000001,...
>>>
>>> So I attempted to compensate with
>>>
>>> import Data.Decimal
>>> map (roundTo 2) [1.00,1.01..2.0]
>>>
>>> I don't have to do it this way if there is another rounding function to
>>> correct the float overrun issue.
>>>
>>>
>>>
>>> On Wed, Feb 17, 2021 at 2:43 PM Francesco Ariis <fa-ml at ariis.it> wrote:
>>>
>>>> Il 17 febbraio 2021 alle 14:17 Galaxy Being ha scritto:
>>>> > How would I install it globally? I'm not using projects, I'm just at
>>>> the
>>>> > ghci REPL.
>>>>
>>>> Most likely
>>>>
>>>>     cabal install --lib Decimal
>>>>
>>>> Check what Tom has said too —F
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