RosettaCodeData/Task/S-Expressions/TXR/s-expressions-1.txr
2016-12-05 22:15:40 +01:00

44 lines
884 B
Text

@(define float (f))@\
@(local (tok))@\
@(cases)@\
@{tok /[+\-]?\d+\.\d*([Ee][+\-]?\d+)?/}@\
@(or)@\
@{tok /[+\-]?\d*\.\d+([Ee][+\-]?\d+)?/}@\
@(or)@\
@{tok /[+\-]?\d+[Ee][+\-]?\d+/}@\
@(end)@\
@(bind f @(flo-str tok))@\
@(end)
@(define int (i))@\
@(local (tok))@\
@{tok /[+\-]?\d+/}@\
@(bind i @(int-str tok))@\
@(end)
@(define sym (s))@\
@(local (tok))@\
@{tok /[^\s()]+/}@\
@(bind s @(intern tok))@\
@(end)
@(define str (s))@\
@(local (tok))@\
@{tok /"(\\"|[^"])*"/}@\
@(bind s @[tok 1..-1])@\
@(end)
@(define atom (a))@\
@(cases)@\
@(float a)@(or)@(int a)@(or)@(str a)@(or)@(sym a)@\
@(end)@\
@(end)
@(define expr (e))@\
@(cases)@\
@/\s*/@(atom e)@\
@(or)@\
@/\s*\(\s*/@(coll :vars (e))@(expr e)@/\s*/@(last))@(end)@\
@(end)@\
@(end)
@(freeform)
@(expr e)@junk
@(output)
expr: @(format nil "~s" e)
junk: @junk
@(end)