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[REBOL] Re: Series Index Discussion (Was: Core 2.5.5. Beta)

From: nitsch-lists:netcologne at: 25-Feb-2003 22:13

Carl Sassenrath wrote: [snip]
> > 4. We treat "going past the end" of a series as an exception. > Fundamental natives > like PICK handle it by returning NONE. Secondary natives handle it by > causing an > error (e.g. FIRST, SECOND, THIRD, etc.). This is done so you don't > have to write > special code every time you use FIRST, because if you did, you might > as well use > PICK or LENGTH?. The FIRST native would not offer a coding advantage. > > 5. It has been proposed that there are three functions that would > provide a more > flexible method of indexing series. We are willing to make these into > Natives if > that is possible (that is, they don't require changes to existing > datatype formats, > they don't require special static storage per series that must be managed > and garbage collected, and they can be applied to all series > datatypes, not just > blocks and strings, but also to hashes, lists, ports). >
i like the effect of returning 'none when out of series. allows stuff like face/text: any[ pick data index "default string"] but i think the out-of-range trick is a bit hidden. could it make sense to have versions with and without error-checking, 'pick and 'pick? or something, to code more specific?