Paths

Hi Rebols, here is a polished version of Do-path, which behaves better in a lot of circumstances. Regards Ladislav Rebol [ Title: "Do-path" File: %do-path.r Author: "Ladislav Mecir" Email: [lmecir--mbox--vol--cz] Date: 22/11/2000 Purpose: { A referentially transparent way to invoke paths in Rebol } Category: [General] ] do-path: function [ { A referentially transparent way to invoke a path. Usage: do-path [something /r1 /r2 ... /end-path a1 a2 ...] /end-path can be omitted, if no args are supplied. Values between Something and /end-path are ignored, if they don't evaluate to refinements. } [throw] blk [block!] ] [something path ref] [ set/any [something blk] do/next blk path: make path! reduce [ either word? get/any 'something [something] ['something] ] until [ any [ empty? blk ( set/any [ref blk] do/next blk if refinement? get/any 'ref [ not if /end-path <> ref [ insert tail :path to word! ref ] ] ) ] ] do head insert/only copy blk :path ] { ;Joel's examples: bunchanums: [3 1 35 8 4 5 52 42 19 13 32 43 81 2 6 34 46] tally: make object! [ tot: 0 zero: does [tot: 0] up: func [/by n [number!]] [tot: tot + either by [n] [1]] down: func [/by n [number!]] [tot: tot - either by [n] [1]] now?: does [tot] ] ; Joel's example #1: use [evens odds] [ evens: make tally [] odds: make tally [] foreach num bunchanums [ do-path [either even? num [evens] [odds] /up /by /end-path num] ] print ["evens:" do-path [evens /now?] " odds:" do-path [odds /now?]] ] ; Result: ; evens: 226 odds: 200 ; Joel's example #2: use [diffs] [ diffs: make tally [] foreach num bunchanums [ do-path [diffs either even? num [/up] [/down] /by /end-path num] ] print ["net sum:" do-path [diffs /now?]] ] ; Result: ; net sum: 26 ; Example #3: do-path [now /time /second] ; Example #4: probe head do-path [:insert if find ask "Only?(y/n) " "y" [/only] /end-path copy [] [1]] }

Hi, sorry for posting "the same thing" twice, but I realized, that the program shall not ignore integers as refinements. Regards Ladislav Rebol [ Title: "Do-path" File: %do-path.r Date: 23/11/2000 Author: "Ladislav Mecir" Email: [lmecir--mbox--vol--cz] Purpose: { A referentially transparent way to invoke paths in Rebol } Category: [General] ] do-path: function [ { A referentially transparent way to invoke a path. Usage: do-path [something /r1 /r2 ... /end-path a1 a2 ...] /end-path can be omitted, if no args are supplied. Values between Something and /end-path are ignored, if they don't evaluate to refinements or integers. } [throw] blk [block!] ] [something path ref] [ set/any [something blk] do/next blk path: make path! reduce [ either word? get/any 'something [something] ['something] ] until [ any [ empty? blk ( set/any [ref blk] do/next blk if any [ refinement? get/any 'ref integer? get/any 'ref ] [ not if /end-path <> ref [ insert tail :path either refinement? ref [ to word! ref ] [ ref ] ] ] ) ] ] do head insert/only copy blk :path ] { ;Joel's examples: bunchanums: [3 1 35 8 4 5 52 42 19 13 32 43 81 2 6 34 46] tally: make object! [ tot: 0 zero: does [tot: 0] up: func [/by n [number!]] [tot: tot + either by [n] [1]] down: func [/by n [number!]] [tot: tot - either by [n] [1]] now?: does [tot] ] ; Joel's example #1: use [evens odds] [ evens: make tally [] odds: make tally [] foreach num bunchanums [ do-path [either even? num [evens] [odds] /up /by /end-path num] ] print ["evens:" do-path [evens /now?] " odds:" do-path [odds /now?]] ] ; Result: ; evens: 226 odds: 200 ; Joel's example #2: use [diffs] [ diffs: make tally [] foreach num bunchanums [ do-path [diffs either even? num [/up] [/down] /by /end-path num] ] print ["net sum:" do-path [diffs /now?]] ] ; Result: ; net sum: 26 ; Example #3: do-path [now /time /second] ; Example #4: probe head do-path [:insert if find ask "Only?(y/n) " "y" [/only] /end-path copy [] [1]] ; Example #5: a: [1 2 3] do-path [a 1 + 1] }