http://snippets.dzone.com/posts Thu, 07 Aug 2008 14:24:32 GMT DZone Snippets: parse-int-values code http://snippets.dzone.com/posts/show/1494 <code> <br />parse-int-values: func [ <br /> "Parses and returns integer values, each <n> chars long in a string." <br /> input [any-string!] <br /> spec [block!] "Dialected block of commands: <n>, skip <n>, done, char, or string" <br /> /local <br /> gen'd-rules ; generated rules <br /> result ; what we return to the caller <br /> emit emit-data-rule emit-skip-rule emit-literal-rule emit-data <br /> digit= n= literal= <br /> int-rule= skip-rule= literal-rule= done= build-rule= <br /> data-rule skip-rule <br />][ <br /> ; This is where we put the rules we build; our gernated parse rules. <br /> gen'd-rules: copy [] <br /> ; This is where we put the integer results <br /> result: copy [] <br /> <br /> ; helper functions <br /> emit: func [rule n] [append gen'd-rules replace copy rule 'n n] <br /> emit-data-rule: func [n] [emit data-rule n] <br /> emit-skip-rule: func [n] [emit skip-rule n] <br /> emit-literal-rule: func [value] [append gen'd-rules value] <br /> emit-data: does [append result to integer! =chars] <br /> <br /> ; Rule templates; used to generate rules <br /> ;data-rule: [copy =chars n digit= (append result to integer! =chars)] <br /> data-rule: [copy =chars n digit= (emit-data)] <br /> skip-rule: [n skip] <br /> <br /> ; helper parse rules <br /> digit=: charset [#"0" - #"9"] <br /> n=: [set n integer!] <br /> literal=: [set lit-val [char! | any-string!]] <br /> <br /> ; Rule generation helper parse rules <br /> int-rule=: [n= (emit-data-rule n)] <br /> skip-rule=: ['skip n= (emit-skip-rule n)] <br /> literal-rule=: [literal= (emit-literal-rule lit-val)] <br /> done=: ['done (append gen'd-rules [to end])] <br /> <br /> ; This generates the parse rules used against the input <br /> build-rule=: [some [skip-rule= | int-rule= | literal-rule=] opt done=] <br /> <br /> ; We parse the spec they give us, and use that to generate the <br /> ; parse rules used against the actual input. If the spec parse <br /> ; fails, we return none (maybe we should throw an error though); <br /> ; if the data parse fails, we return false; otherwise they get <br /> ; back a block of integers. Have to decide what to do if they <br /> ; give us negative numbers as well. <br /> either parse spec build-rule= [ <br /> either parse input gen'd-rules [result] [false] <br /> ] [none] <br />] <br />comment { <br /> test: func [val spec] [print mold parse-int-values val spec] <br /> test "20060228T190000" [4 2 2 skip 1 2 2 2] <br /> test "20060228T190000" [4 2 2 #"T" 2 2 2] <br /> test "20060228T190000Z" [4 2 2 #"T" 2 2 2 #"Z"] <br /> test "20060228T190000Z" [4 2 2 #"T" 2 2 2 done] <br /> test %2006021509450004.jpg [4 2 2 2 2 4 skip 4] <br /> test %2006021509450004.jpg [4 2 2 2 2 4 done] <br /> ; tests that *should* fail <br /> ; Bad spec <br /> test "20060228T190000Z" [4 2 x #"T" 2 2 2] <br /> test "20060228T190000Z" [4 2 2 #"T" 2.5 2 2] <br /> ; Bad input <br /> test "20060228T190000Z" [4 2 2 #"T" 2 2 2] <br /> test "2000228T190000Z" [4 2 2 #"T" 2 2 2 done] <br /> test "20060228x190000Z" [4 2 2 #"T" 2 2 2 done] <br />} <br /></code> Thu, 16 Feb 2006 00:28:44 GMT http://snippets.dzone.com/posts/show/1494 gregg.irwin (Gregg Irwin)