(* StringCvt -- new basis 1995-04-06, 1995-10-26, 1996-04-01, 1997-06-03 *) local    prim_val sub_      : string -> int -> char  = 2 "get_nth_char";    prim_val mkstring_ : int -> string          = 1 "create_string";    prim_val fill_     : string -> int -> int -> char -> unit                                                 = 4 "fill_string";    prim_val blit_     : string -> int -> string -> int -> int -> unit                                                 = 5 "blit_string";    prim_val set_nth_  : string -> int -> char -> unit                                                 = 3 "set_nth_char";     fun sub_string_ s start len =	let val res = mkstring_ len	in blit_ s start res 0 len; res end in datatype radix = BIN | OCT | DEC | HEX;datatype realfmt =     SCI of int option	(* scientific,  arg = # dec. digits, dflt=6 *)  | FIX of int option   (* fixed-point, arg = # dec. digits, dflt=6 *)  | GEN of int option 	(* auto choice of the above,                *)                        (* arg = # significant digits, dflt=12      *) type cs = int		(* the state of a string character source   *) type ('a, 'b) reader = 'b -> ('a * 'b) option fun scanString scan s =    let val len = size s	fun getc i = if i >= len then NONE 		     else SOME (sub_ s i, i+1)    in case scan getc 0 of	NONE          => NONE      | SOME (res, _) => SOME res    end; fun dropl p getc =     let fun h src =	case getc src of	    NONE          => src	  | SOME(c, rest) => if p c then h rest else src    in h end; (* skipWS getc = dropl Char.isSpace getc; here specialized for efficiency: *)fun skipWS getc =     let fun h src =	case getc src of	    NONE          => src	  | SOME(c, rest) => 		if c = #" " orelse #"\009" <= c andalso c <= #"\013" 		    then h rest 		else src    in h end; fun splitl p getc =    let val max = ref 15	val tmp = ref (mkstring_ (!max))	fun realloc () =	    let val newmax = 2 * !max		val newtmp = mkstring_ newmax	    in 		blit_ (!tmp) 0 newtmp 0 (!max);		max := newmax;		tmp := newtmp	    end	fun h len src =	    case getc src of		NONE          => (sub_string_ (!tmp) 0 len, src)	      | SOME(c, rest) => 		    if p c then 			(if len >= !max then realloc () else ();			 set_nth_ (!tmp) len c;			 h (len+1) rest)		    else			(sub_string_ (!tmp) 0 len, src)    in h 0 end; fun takel p getc src = #1 (splitl p getc src); fun padLeft c n s =     let val ssize = size s    in if n <= ssize then s       else let val res = mkstring_ n 	    in		fill_ res 0 (n - ssize) c;		blit_ s 0 res (n - ssize) ssize;		res	    end    end;	     fun padRight c n s =     let val ssize = size s    in if n <= ssize then s       else let val res = mkstring_ n 	    in		blit_ s 0 res 0 ssize;		fill_ res ssize (n - ssize) c;		res	    end    end; end