REBOL [ Title: "Extend" Author: "Vincent Ecuyer" Date: 31-Jan-2013 Version: 1.0.0 File: %extend.r Purpose: {Extends a series with sequential or duplicate values.} Usage: { extend/to/cut value (series!) length (integer!) with: value - the series to modifies length - either the number of items to append (or retire, if it's negative and /cut is used), or, with /to, the total number of items /to - the 'length is the total length (without /cut, dont do anything is the series is too long) /cut - shortens the series if it's too long (with /to), or if length is negative (without /to) /dup - duplicates values (repeat the existing values, but doesn't try to continue a sequence) Empty series : appends none or null (0) values >> extend [] 10 == [none none none none none none none none none none] >> extend #{} 10 == #{00000000000000000000} One element : builds an incrementing sequence >> extend [1] 10 == [1 2 3 4 5 6 7 8 9 10 11] >> extend/to "a" 26 == "abcdefghijklmnopqrstuvwxyz" /dup disables the incrementation >> extend/dup [1] 10 == [1 1 1 1 1 1 1 1 1 1 1] Two elements or more : tries to continue the series >> extend [0 5] 6 == [0 5 10 15 20 25 30 35] >> extend [1 3 5] 3 == [1 3 5 7 9 11] >> extend [1 5 3] 3 == [1 5 3 1 5 3] It works with date!, time!, char!, number!, and tuple! elements >> extend/to reduce [now/date] 5 == [30-Jan-2013 31-Jan-2013 1-Feb-2013 2-Feb-2013 3-Feb-2013 ] >> extend/to [08:00:00 08:30:00] 8 == [8:00 8:30 9:00 9:30 10:00 10:30 11:00 11:30] >> extend/to [0.0.0.127 64.0.1.127] 4 == [0.0.0.127 64.0.1.127 128.0.2.127 192.0.3.127] /cut is used to shorten the series >> extend/cut [1 2 3 4 5 6] -1 == [1 2 3 4 5] >> extend/cut/to [0 1 2 3 4 5 6] 3 == [0 1 2] Non-numeric elements or mixed elements : repeats the values >> extend ["cat" "rabbit" "dog"] 5 == ["cat" "rabbit" "dog" "cat" "rabbit" "dog" "cat" "rabbit"] >> extend/to [5 dog 15] 8 == [5 dog 15 5 dog 15 5 dog] } Library: [ level: 'intermediate platform: 'all type: [tool function] domain: none tested-under: [ view 2.7.8.2.5 on [Macintosh osx-x86] core 2.101.0.2.5 on [Macintosh osx-x86] ] support: none license: 'apache-v2.0 see-also: none ] ] extend: func [ "Extends a series with sequential or duplicate values." value [series!] "The series to modify." length [integer!] "The number of values to append." /to "The specified length is the total length." /dup "Duplicates only." /cut "Removes the value past the specified length." /local x-inc x-dup any-number? ][ ; /to refinement : 'length is total length if to [length: length - length? value] ; nothing to append if length <= zero [ ; /cut refinement : clears the unwanted values if cut [clear at tail value length] return value ] ; datatypes who accepts operators any-number?: func [value][ found? find [decimal! integer! date! time! money! pair! tuple! char!] type?/word value ] ; increments series x-inc: func [data] either any [any-string? value binary? value] [ [insert tail value (to-char last value) + data] ][ [insert tail value (last value) + data] ] ; duplicates series x-dup: does either any [any-string? value binary? value] [ [insert/only tail value to-char first value] ][ [insert/only tail value first value] ] ; /dup refinement : only duplicates values if all [dup not empty? value] [ loop length [x-dup value: next value] return head value ] ; mode auto switch/default length? value [ ; empty series : fills it with null or none content 0 [ insert/dup value either any [any-string? value binary? value][#"^@"][none] length ] ; one item : choose according to the datatype 1 [ either any-number? first value [ ; number : increments it loop length [x-inc 1] ][ ; other value : duplicates it insert/only/dup value either any [any-string? value binary? value][ to-char first value ][ first value ] length ] ] ; two items : choose according to the datatype and the values 2 [ either all [any-number? first value any-number? second value][ ; two numbers : completes with the same difference between values loop length compose [x-inc ((second value) - first value)] ][ ; otherwise : duplicates the values loop length [x-dup value: next value] ] ] ][ ; more items : choose according to the datatype and the values either all [ ; tests if the values are a sequence of numbers until [ if any [ not any-number? value/1 (type? value/1) <> type? value/2 (type? value/2) <> type? value/3 (value/2 - value/1) <> (value/3 - value/2) ][break/return false] tail? next next value: next value ] value: head value ][ ; sequence of numbers : completes it loop length compose [x-inc ((second value) - first value)] ][ ; misc values : duplicates it loop length [x-dup value: next value] ] ] ; head of the modified series head value ]