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[REBOL] Re: Hungarian Alphabet Sort (was Re: Collation sequence - proper and eff

From: carl:cybercraft at: 16-May-2002 0:30

On 15-May-02, G. Scott Jones wrote:
> From: "Volker Nitsch" > ... >> not sure if this helps, but since i spended some time to it, >> i post ;) > <snipped code> > Hi, Volker, > Neat idea. Kind of like a good cut of beef, I'm going to have to > chew on it a bit to fully understand its potential. Thanks for the > trans-atlantic volley ball pass.
Glad you could work it out, as I couldn't make head nor tail of it. (: Anyway, I've played around with my idea for sorting according to a pattern, and while I'm not sure if the following code's very fast (or bug-free:), like Volker, I post. There's two functions: One to take a pattern for creating a rule from and another to use the rule to sort strings or blocks of strings with. First, the functions... pattern-rule: func [ "Create a rule for use by pattern-sort." pattern [string! block!] "An ordered pattern." /local rule n ][ rule: copy [] n: 1 forall pattern [ append rule reduce [pattern/1 to-paren reduce ['r n] '|] n: n + 1 ] append rule reduce ['skip to-paren reduce ['r n]] reduce ['some rule] ] pattern-sort: func [ {Sort a string or block of strings based on a rule created by pattern-rule.} series [string! block!] "Series to sort." rule [block!] "Pattern rule." /reverse "Reverse sort order." /local ptrs blk r pos val ][ ptrs: copy [] blk: copy [] r: func [n][append/only blk n] bind rule 'r either string? series [ parse/case series rule pos: 1 foreach n blk [ append/only ptrs reduce [ n pick rule/2 (n - 1) * 3 + 1 ] val: next first back tail ptrs if 'skip = val/1 [change val pick series pos] pos: pos + either char? val/1 [1][length? val/1] ] ][ forall series [ clear blk parse/case series/1 rule append/only ptrs copy blk append last ptrs series/1 ] ] either reverse [sort/reverse ptrs][sort ptrs] clear series forall ptrs [append series last ptrs/1] series ] And some examples of use...
>> rule-1: pattern-rule "aAbBcC"
== [some [#"a" (r 1) | #"A" (r 2) | #"b" (r 3) | #"B" (r 4) | #"c" (r 5) | #"C" (r 6) | skip (r 7)]]
>> pattern-sort "AacCBb" rule-1
== "aAbBcC"
>> pattern-sort ["Abc" "abc" "aBC" "ABC"] rule-1
== ["abc" "aBC" "Abc" "ABC"]
>> pattern-sort/reverse ["Abc" "abc" "aBC" "ABC"] rule-1
== ["ABC" "Abc" "aBC" "abc"]
>> rule-2: pattern-rule "AaBbCc"
== [some [#"A" (r 1) | #"a" (r 2) | #"B" (r 3) | #"b" (r 4) | #"C" (r 5) | #"c" (r 6) | skip (r 7)]]
>> pattern-sort "AacCBb" rule-2
== "AaBbCc"
>> pattern-sort ["Abc" "abc" "aBC" "ABC"] rule-2
== ["ABC" "Abc" "aBC" "abc"]
>> rule-3: pattern-rule ["a" "A" "b" "B" "ch" "c" "C"]
== [some ["a" (r 1) | "A" (r 2) | "b" (r 3) | "B" (r 4) | "ch" (r 5) | c (r 6) | "C" (r 7) | skip (r 8)]]
>> pattern-sort "abcABCchCbA" rule-3
== "aAAbbBchcCC"
>> pattern-sort ["AabA" "chab" "chAB" "cchc" "achA"] rule-3
== ["achA" "AabA" "chab" "chAB" "cchc"] It seems to work and might be of some use, but I'd test it well before trusting it. It's had no real-world tests at all... -- Carl Read