[Newbies] closed and open interval
Randal L. Schwartz
merlyn at stonehenge.com
Mon Nov 24 17:36:06 UTC 2008
>>>>> "Bert" == Bert Freudenberg <bert at freudenbergs.de> writes:
Bert> On 24.11.2008, at 17:46, Randal L. Schwartz wrote:
>>>>>>> "Filip" == Filip Malczak <filet00 at gmail.com> writes:
Filip> You can always make subclass of Interval for example OpenedInterval
>> , add
Filip> two variables: left and right.Make new methods:
OpenedInterval> from: aNumber to: aNumber left: aBoolean
OpenedInterval> from: aNumber to: aNumber right: aBoolean
OpenedInterval> from: aNumber to: aNumber left: aBoolean right: aBoolean
>> You're exposing implementation there.
Bert> How so?
You're requiring the user to do their own encoding of "open = true, closed =
false", when that's really no business of the user. And what if you decide
later to encode the four combinations as a single pluggable block or symbol?
Randal L. Schwartz - Stonehenge Consulting Services, Inc. - +1 503 777 0095
<merlyn at stonehenge.com> <URL:http://www.stonehenge.com/merlyn/>
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