gm2-libs-iso/RealIO (The GNU Modula-2 Compiler)

#### 4.4.42 gm2-libs-iso/RealIO ¶

    DEFINITION MODULE RealIO;

      (* Input and output of real numbers in decimal text form
         over specified channels.  The read result is of the
         type IOConsts.ReadResults.
      *)

    IMPORT IOChan;

      (* The text form of a signed fixed-point real number is
           ["+" | "-"], decimal digit, {decimal digit},
           [".", {decimal digit}]

         The text form of a signed floating-point real number is
           signed fixed-point real number,
           "E", ["+" | "-"], decimal digit, {decimal digit}
      *)

    PROCEDURE ReadReal (cid: IOChan.ChanId; VAR real: REAL);
      (* Skips leading spaces, and removes any remaining characters
         from cid that form part of a signed fixed or floating
         point number.  The value of this number is assigned to real.
         The read result is set to the value allRight, outOfRange,
         wrongFormat, endOfLine, or endOfInput.
      *)

    PROCEDURE WriteFloat (cid: IOChan.ChanId; real: REAL;
                          sigFigs: CARDINAL; width: CARDINAL);
      (* Writes the value of real to cid in floating-point text form,
         with sigFigs significant figures, in a field of the given
         minimum width.
      *)

    PROCEDURE WriteEng (cid: IOChan.ChanId; real: REAL;
                        sigFigs: CARDINAL; width: CARDINAL);
      (* As for WriteFloat, except that the number is scaled with
         one to three digits in the whole number part, and with an
         exponent that is a multiple of three.
      *)

    PROCEDURE WriteFixed (cid: IOChan.ChanId; real: REAL;
                          place: INTEGER; width: CARDINAL);
      (* Writes the value of real to cid in fixed-point text form,
         rounded to the given place relative to the decimal point,
         in a field of the given minimum width.
      *)

    PROCEDURE WriteReal (cid: IOChan.ChanId;
                         real: REAL; width: CARDINAL);
      (* Writes the value of real to cid, as WriteFixed if the sign
         and magnitude can be shown in the given width, or otherwise
         as WriteFloat.  The number of places or significant digits
         depends on the given width.
      *)

    END RealIO.