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Postings from July 2010
On 2010-07-29 01:39, Jon Lang wrote: > Aaron Sherman wrote: > >>> In smart-match context, "a".."b" includes "aardvark". >>> >> No one has yet explained to me why that makes sense. The continued use of >> ASCII examples, of course, doesn't help. Does "a" .. "b" include "æther"? >> This is where Germans and Swedes, for example, don't agree, but they're all >> using the same Latin code blocks. >> > This is definitely something for the Unicode crowd to look into. But > whatever solution you come up with, please make it compatible with the > notion that "aardvark".."apple" can be used to match any word in the > dictionary that comes between those two words. The key issue here is whethere there is a well defined and meaningful ordering of the characters in question. We keep discussing the nice examples, but how about "apple" .. "ส้ม"? I don't know enough about Unicode to suggest how to solve this. All I can say is that my example above should never return a valid Range object unless there is a way I can specify my own ordering and I use it. >> I've never accepted that the range between two strings of identical length >> should include strings of another length. That seems maximally non-intuitive >> (well, I suppose you could always return the last 100 words of Hamlet as an >> iterable IO object if you really wanted to confuse people), and makes string >> and integer ranges far too divergent. >> > This is why I dislike the notion of the range operator being used to > produce lists: the question of what values you'd get by iterating from > one string value to another is _very_ different from the question of > what string values qualify as being between the two. The more you use > infix:<..> to produce lists, the more likely you are to conflate lists > with ranges. I second the above. Ranges are all about comparing things. $x ~~ $a .. $b means "is $x between $a and $b?". The only broadly accepted comparison of strings is lexicographical comparison. To illustrate the point: wouldn't you find it odd if 2.01 wasn't in between 1.1 and 2.1? Really? Regards, Michael.Thread Previous | Thread Next