[Haskell-cafe] The Good, the Bad and the GUI

[Wojtek Narczyński]

On 13.08.2014 22:49, Steve Schafer wrote:
> On Wed, 13 Aug 2014 22:31:31 +0200, Wojtek Narczy?ski
> <wojtek at power.com.pl> wrote:
>
>> Let's say the user entered:
>>
>> No, Name, Qty, Price
>> --------------------------------------------
>> 1. [        ]   [99] [10]
>> 2. [Water] [    ] [10]
>> 3. [Juice]   [  1] [    ]
>>
>> The GUI should display total of 990
> Why? Why are any of these erroneous line items included in the total? I
> would argue that an incomplete or otherwise erroneous line item is not
> part of the invoice.
Say that the error is merely a warning, for example the user entered 'A' 
which is suspiciously short.
> I don't know of any (reasonable) online merchant that requires the user
> to separately enter item, quantity and price.
Yes, it is terrible. It's called "accounting".