\ 2012-04-06 fsm1.fs

include tempbuffer.fs \ reset append show

variable prev.minus?
variable prev.dpoint?

: digit?  [char] 0  [char] 9 within ;
: dpoint?  [char] . = ;
: minus?   [char] - = ;
: first.minus?
  minus?  prev.minus? @ not  and ;
: first.dpoint?
  dpoint?  prev.dpoint? @ not  and ;
: false true not ;

: legal? ( c -- f )
  dup digit? if
    drop true dup prev.minus? !
  else dup
    first.minus? if
      drop true dup prev.minus? !
    else
      first.dpoint? if
	true dup prev.dpoint? !
      else
	false
      then
    then
  then 
;

: getafix
  reset
  false prev.minus? !
  false prev.dpoint? !
  begin
    key
    dup emit
    dup $0D <> \ exit on CR == &13 == $0D
  while
      dup legal? if append else drop then
  repeat
  drop \ CR
  cr show cr
;