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Annotation of researchv10no/cmd/sml/doc/examples/awk/lex.sml, revision 1.1.1.1

1.1       root        1: (* lex.sml *)
                      2: 
                      3: signature LEX =
                      4: sig
                      5:   val words: string -> string list
                      6: end
                      7: 
                      8: structure Lex1 : LEX =
                      9: struct
                     10: 
                     11:   fun separator " " = true
                     12:     | separator "\t" = true
                     13:     | separator "\n" = true
                     14:     | separator _ = false
                     15: 
                     16:   fun words s =
                     17:       let fun getword(w,[])  = [implode(rev w)]
                     18:            | getword(w,c::rest) = 
                     19:                if separator(c)
                     20:                then implode(rev w) :: skip rest
                     21:                else getword(c::w,rest)
                     22:          and skip [] = []
                     23:            | skip(c::rest) =
                     24:                if separator c
                     25:                then skip rest
                     26:                else getword([c],rest)
                     27:        in skip(explode s)
                     28:       end
                     29: 
                     30: end (* Lex1 *)
                     31: 
                     32: structure Lex2 : LEX =
                     33: struct
                     34: 
                     35:   fun separator " " = true
                     36:     | separator "\t" = true
                     37:     | separator "\n" = true
                     38:     | separator _ = false
                     39: 
                     40:   fun words(s: string) =
                     41:       let val len  = length s
                     42:          fun skip n = 
                     43:              let fun getword m =
                     44:                  if m>=len orelse separator(substring(s,m,1))
                     45:                  then substring(s,n,(m-n))::skip(m+1)
                     46:                  else getword(m+1)
                     47:               in if n>=len
                     48:                  then []
                     49:                  else if separator(substring(s,n,1))
                     50:                  then skip(n+1)
                     51:                  else getword(n+1)
                     52:              end
                     53:        in skip 0
                     54:       end
                     55: 
                     56: end (* Lex2 *)

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