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[REBOL] Re: Millennium + 1 ...

From: lmecir:mbox:vol:cz at: 5-Jan-2001 20:06

My point of view written in Rebol: pick-prop: function [ {Returns the value at the specified place in a series.} [catch throw] series [series!] index [integer!] /back {pick backwards} /or handler [block!] {exception handler} ] [to-skip skipped] [ to-skip: either back [- index] [index - 1] either any [ tail? skipped: skip :series to-skip all [ head? :skipped head? skip :series to-skip + 1 ] ] [ either or [do handler] [ throw make error! {Cannot pick} ] ] [first :skipped] ] A user can choose, if she wants to use the zero-less method of picking like: series: skip [-2 -1 1 2] 2 ; == [1 2] pick-prop :series 1 ; == 1 pick-prop/back :series 1 ; == -1 or use zero and negative numbers. In this case the expressions: pick :series n pick/back :series n are equivalent to pick/back :series 1 - n pick :series 1 - n Regards Ladislav