From mboxrd@z Thu Jan 1 00:00:00 1970 X-Spam-Checker-Version: SpamAssassin 3.4.4 (2020-01-24) on polar.synack.me X-Spam-Level: X-Spam-Status: No, score=-1.3 required=5.0 tests=BAYES_00,INVALID_MSGID autolearn=no autolearn_force=no version=3.4.4 X-Google-Language: ENGLISH,ASCII-7-bit X-Google-Thread: 103376,36208f5925ed5269 X-Google-Attributes: gid103376,public From: Ehud Lamm Subject: Re: non-consecutive ranges Date: 1999/05/01 Message-ID: #1/1 X-Deja-AN: 472896460 References: <7gct90$7hr$1@nnrp1.dejanews.com> Content-Type: TEXT/PLAIN; charset=US-ASCII Organization: The hebrew University of Jerusalem Mime-Version: 1.0 Newsgroups: comp.lang.ada Date: 1999-05-01T00:00:00+00:00 List-Id: The idea of non consecutive ranges come up many times. I find it very remarkable. Consider how costly vvalidity checks for such types can be. Consider a type which is based on integer, but consists of only the prime numbers... This is a nic example of "over abstracting." This idea ofranges is so appealing in many situations that we tend to quite simply SEE how the abstraction is logically extended to such "sets of ranges." Many don't even see this as new, and are surprised to see that some syntax they come up with, doesn't compile. This is one of example of the amazing power of good abstractions - we lose site of the implementation details altogether, and so don't know where the applicability of the abstraction ends. We can connect this to the idea of abstraction in general. Great scientists are usually regarded to be those that aside from using various scientific abstractions (like differntial equations, newtonian mechanics, thermodynamics etc.), grasp the inner details - thus knowing when things are applicable and when they are not and the theory etc. needs to be modified. Analogy can many times be the key here, but knowing where the analogies end is the crucial part. (This sentence may be seen as a pointer to Doug Hofstadter's theories of analogy making). Ehud Lamm mslamm@pluto.mscc.huji.ac.il