gm2-libs-log/RealConversions (The GNU Modula-2 Compiler)

#### 4.2.20 gm2-libs-log/RealConversions ¶

    DEFINITION MODULE RealConversions ;

    EXPORT QUALIFIED SetNoOfExponentDigits,
                     RealToString, StringToReal,
                     LongRealToString, StringToLongReal ;

    (*
       SetNoOfExponentDigits - sets the number of exponent digits to be
                               used during future calls of LongRealToString
                               and RealToString providing that the width
                               is sufficient.
                               If this value is set to 0 (the default) then
                               the number digits used is the minimum necessary.
    *)

    PROCEDURE SetNoOfExponentDigits (places: CARDINAL) ;

    (*
       RealToString - converts a real, r, into a right justified string, str.
                      The number of digits to the right of the decimal point
                      is given in, digits.  The value, width, represents the
                      maximum number of characters to be used in the string,
                      str.

                      If digits is negative then exponent notation is used
                      whereas if digits is positive then fixed point notation
                      is used.

                      If, r, is less than 0.0 then a '-' preceeds the value,
                      str.  However, if, r, is >= 0.0 a '+' is not added.

                      If the conversion of, r, to a string requires more
                      than, width, characters then the string, str, is set
                      to a nul string and, ok is assigned FALSE.

                      For fixed point notation the minimum width required is
                      ABS(width)+8

                      For exponent notation the minimum width required is
                      ABS(digits)+2+log10(magnitude).

                      if r is a NaN then the string 'nan' is returned formatted and
                      ok will be FALSE.
    *)

    PROCEDURE RealToString (r: REAL; digits, width: INTEGER;
                            VAR str: ARRAY OF CHAR; VAR ok: BOOLEAN) ;

    (*
       LongRealToString - converts a real, r, into a right justified string, str.
                          The number of digits to the right of the decimal point
                          is given in, digits. The value, width, represents the
                          maximum number of characters to be used in the string,
                          str.

                          If digits is negative then exponent notation is used
                          whereas if digits is positive then fixed point notation
                          is used.

                          If, r, is less than 0.0 then a '-' preceeds the value,
                          str. However, if, r, is >= 0.0 a '+' is not added.

                          If the conversion of, r, to a string requires more
                          than, width, characters then the string, str, is set
                          to a nul string and, ok is assigned FALSE.

                          For fixed point notation the minimum width required is
                          ABS(width)+8

                          For exponent notation the minimum width required is
                          ABS(digits)+2+log10(magnitude).

                          Examples:
                          RealToString(100.0, 10, 10, a, ok)       ->  '100.000000'
                          RealToString(100.0, -5, 12, a, ok)       ->  '  1.00000E+2'

                          RealToString(123.456789, 10, 10, a, ok)  ->  '123.456789'
                          RealToString(123.456789, -5, 13, a, ok)  ->  '    1.23456E+2'

                          RealToString(123.456789, -2, 15, a, ok)  ->  '          1.23E+2'

                          if r is a NaN then the string 'nan' is returned formatted and
                          ok will be FALSE.
    *)

    PROCEDURE LongRealToString (r: LONGREAL; digits, width: INTEGER;
                                VAR str: ARRAY OF CHAR; VAR ok: BOOLEAN) ;

    (*
       StringToReal - converts, str, into a REAL, r. The parameter, ok, is
                      set to TRUE if the conversion was successful.
    *)

    PROCEDURE StringToReal (str: ARRAY OF CHAR; VAR r: REAL; VAR ok: BOOLEAN) ;

    (*
       StringToLongReal - converts, str, into a LONGREAL, r. The parameter, ok, is
                          set to TRUE if the conversion was successful.
    *)

    PROCEDURE StringToLongReal (str: ARRAY OF CHAR; VAR r: LONGREAL; VAR ok: BOOLEAN) ;

    END RealConversions.