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[REBOL] Re: Linguistic influences

From: lmecir:mbox:vol:cz at: 12-May-2002 10:55

Hi Volker and Joel, 1) I didn't want to criticize the ineffectivity of the algorithm. I would rather say, that what matters to me may be a "naturality" of the algorithm. 2) Joel's examples as well as Volker's look to me as "top down writing style", while my attempt uses a "bottom up" approach. I am convinced, that the "bottom up style" can be used to improve the readability. 3) Volker is right, that the introduction of iteration using FOREACH simplifies the code. For the comparison purposes, here is an iterative version of FLAT-APPEND: flat-append: func [ series [series! port!] value [any-type!] ] [ either block? get/any 'value [ foreach element value [ flat-append :series get/any 'element ] ] [ insert/only tail :series get/any 'value ] :series ] It is advisable to use the iteration, where it looks more natural/readable (at least in Rebol). 4) I noticed a paradox: the most effective way of assembling blocks is to use APPEND (or INSERT TAIL), but we do not have it as a native. Moreover, the APPEND function should be enhanced to allow the same types of arguments/refinements as INSERT does. (sending as an enhancement request to feedback too). append: function [ {Appends a value to the tail of a series and returns the series.} [catch] series [series! port! bitset!] "Series at point to insert" value [any-type!] "The value to insert" /part "Limits to a given length or position." range [number! series! port!] /only "Inserts a series as a series." /dup "Duplicates the insert a specified number of times." count [number!] ] [path block] [ path: to path! [insert] block: reduce [:path 'tail :series] insert/only tail block get/any 'value if part [ insert tail path 'part insert/only tail block :range ] if only [ insert tail path 'only insert tail block :range ] if dup [ insert tail path 'dup insert tail block :count ] throw-on-error block :series ] The CHANGE function should be enhanced too, to allow ANY-TYPE! VALUE argument. -L ----- Original Message ----- From: "Joel Neely" Hi, Volker and Ladislav, Volker Nitsch wrote:
> aha! hmm2: all this inserting at front, and recursion? (coding) >
> obviously you coded for example, not performance ;) >
Absolutely! I'm under no illusion that the sample code offered was the best algorithm/approach for the problem. That the first version was just leftovers from some benchmarking I had done a while back -- it was just the first fragment of code that came to hand that had some deeply-nested expressions. I assure one and all that I do NOT recommend constructing blocks from right to left! Of course, that sentence betrays that my native/habitual language is Indo-European-based (reading left-to-right) rather than Hebrew or Arabic (reading right-to-left) or ancient Greek (when written in boustrophedon). -jn- -- ; Joel Neely joeldotneelyatfedexdotcom REBOL [] do [ do func [s] [ foreach [a b] s [prin b] ] sort/skip do function [s] [t] [ t: "" foreach [a b] s [repend t [b a]] t ] { | e s m!zauafBpcvekexEohthjJakwLrngohOqrlryRnsctdtiub} 2 ]