26 Feb
2007
26 Feb
'07
5:54 p.m.
But consider also how those same languages handle the problem of "item not found", whether it's not finding a substring in a larger string, an object in a collection, or a web resource. Nearly always, the programmer expects to check for the possibility that the item wasn't found, and so it's natural in those cases to return nil (or whatever) to say so. Only a few raise an exception when something isn't found. Smalltalk's common way of having an #...ifNotFound: block is another kind of exception handling.
What would you expect from iterating over #(1 nil 2) ? The second #next will return nil. But it does not indicate the end of stream.
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Damien Cassou