Fw: Nedd to use an indirection like operation during parsing

----- Original Message ----- From: "Gerard Cote" <[gerardcote--sympatico--ca]> To: <[rebol-list--rebol--com]> Sent: Friday, June 17, 2005 8:48 PM Subject: [REBOL] Nedd to use an indirection like operation during parsing Hello list, Below is some relatively easy parsing rules even if it took long for me to put pieces in place. The object of these rules is to recognize between different representations of numbers. Up to now I succeeded to let REBOL distinguish between the followinf reps: a binary number, an octal number, a decimal number, an hexadecimal number and an identifier too. However even if REBOL can catch the identifier I am unable to get the value associated with it. Can someone help with an explanation or better with a solution to get the requested value. Thanks in advance! Gerard issue-rules: make object! [ expr: [copy my-num1 bin-number (print-info my-num1 "bin") to end | copy my-num2 oct-number (print-info my-num2 "oct") to end | copy my-num3 hex-number (print-info my-num3 "hex") to end | copy my-num4 dec-number (print-info my-num4 "dec") to end | copy my-ident identifier (print-info my-ident "ident") to end ] letter-b: charset "bB" letter-o: charset "oO" letter-x: charset "xX" bin-digit: charset "01" bin-digits: [some bin-digit] bin-number: [bin-digits letter-b] oct-digit: charset "01234567" oct-digits: [some oct-digit] oct-number: [oct-digits letter-o] dec-digit: charset "0123456789" hex-digit: union charset "abcdefABCDEF" dec-digit hex-digits: [some hex-digit] hex-number: [hex-digits letter-x] dec-number: [0 1 "-" [unsigned-integer | decimal-number | scientific-notation-decimal-number]] unsigned-integer: [some digit] decimal-number: [0 1 unsigned-integer decimal-fraction] decimal-fraction: ["." unsigned-integer] scientific-notation-decimal-number: [mantissa "E" ["+" | "-" | none] exponent] mantissa: [unsigned-integer | decimal-number] exponent: [unsigned-integer] identifier: [letter any [digit | letter | letter-sep]] letter: charset [#"A" - #"Z" #"a" - #"z"] letter-sep: charset "_-" digit: charset "0123456789" print-info: func [info info-type][ either any [info-type = "bin" info-type = "oct" info-type = "hex"][ info-num: remove back tail info info-num: head info ][ info-num: info ] either [info-type = "ident"][ print :info ][ print info ] print info-type ] ] ; Calls to the above parsing rules follow for each "data representation" (Bin, oct, hex, dec, Ident) ; The only remaining problem - for the moment - is : I can't get the Ident value in addition ; to its name and type as was done for the other datatypes nom: 250 parse to-string [43.21] issue-rules/expr parse to-string [1.23E4] issue-rules/expr parse to-string [#c2x] issue-rules/expr parse to-string [#123o] issue-rules/expr parse to-string [#0101b] issue-rules/expr parse to-string [var-name] issue-rules/expr Here is an exec of the above code:

>> nom: 250

>> parse to-string [43.21] issue-rules/expr

>> parse to-string [1.23E4] issue-rules/expr

>> parse to-string [#c2x] issue-rules/expr

>> parse to-string [#123o] issue-rules/expr

>> parse to-string [#0101b] issue-rules/expr

>> parse to-string [var-name] issue-rules/expr