Re: [Gm2] Re: ISO & SysClock.def ?

[Andreas Fischlin]

Implementation typically very platform dependent. :-(

Here an implementation that works for Macintosh from P1 Modula-2 (I guess no one is interested in Classic variants, which I could also provide):

DEF:
------

DEFINITION MODULE SysClock;

(* Facilities for accessing a system clock that records the date and time of day *)

CONST
  maxSecondParts = 0;
 
TYPE
  Month    = [1 .. 12];
  Day      = [1 .. 31];
  Hour     = [0 .. 23];
  Min      = [0 .. 59];
  Sec      = [0 .. 59];
  Fraction = [0 .. maxSecondParts];
  UTCDiff  = [-780 .. 720];
  DateTime =
    RECORD
      year:      CARDINAL;
      month:     Month;
      day:       Day;
      hour:      Hour;
      minute:    Min;
      second:    Sec;
      fractions: Fraction;      (* parts of a second *)
      zone:      UTCDiff;       (* Time zone differential factor which is the number
                                   of minutes to add to local time to obtain UTC. *)
      summerTimeFlag: BOOLEAN;  (* Interpretation of flag depends on local usage. *)
    END;
 
PROCEDURE CanGetClock (): BOOLEAN;
  (* Returns TRUE if a system clock can be read; FALSE otherwise *)
 
PROCEDURE CanSetClock (): BOOLEAN;
  (* Returns TRUE if a system clock can be set; FALSE otherwise *)
 
PROCEDURE IsValidDateTime (userData: DateTime): BOOLEAN;
  (* Returns TRUE if the value of userData represents a valid date and time; FALSE otherwise *)
 
PROCEDURE GetClock (VAR userData: DateTime);
  (* If possible, assigns system date and time of day to userData *)
 
PROCEDURE SetClock (userData: DateTime);
  (* If possible, sets the system clock to the values of userData *)
 
END SysClock.



MOD:
--------

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****************************************)



IMPLEMENTATION MODULE SysClock;

  (* Access to system date and time of day clock *)

FROM BasicTime IMPORT TimeRec, TimeRecPtr, time, localtime;
FROM SYSTEM IMPORT INT32, ADR;

PROCEDURE CanGetClock (): BOOLEAN;
  (* Tests if a clock can be read *)
BEGIN
    RETURN TRUE;
END CanGetClock;
 
PROCEDURE CanSetClock (): BOOLEAN;
  (* Tests if a clock can be set *)
BEGIN
    RETURN FALSE;                                                    (*8.0*)
END CanSetClock;
 
PROCEDURE IsValidDateTime (userData: DateTime): BOOLEAN;
  (* Tests if the value of userData is a valid date and time representation *)

    PROCEDURE LeapYear (year: CARDINAL): BOOLEAN;
    BEGIN
        RETURN (year MOD 4 = 0) AND (year MOD 400 <> 0)
    END LeapYear;

BEGIN
    WITH userData DO
        RETURN (day <> 0) AND (
            (month IN BITSET {1, 3, 5, 7, 8, 10, 12}) AND (day <= 31) OR
            (month IN BITSET {4, 6, 9, 11}) AND (day <= 30) OR
            (month =2) AND NOT LeapYear (year) AND (day <= 28) OR
            (month =2) AND LeapYear (year) AND (day <= 29)
        );
    END(*WITH*);
END IsValidDateTime;
 
PROCEDURE GetClock (VAR userData: DateTime);
  (* Assigns local date and time of day to userData *)
VAR
    sysTime: TimeRecPtr;
    t: INT32;
BEGIN
    t := time (NIL);
    sysTime := localtime (ADR (t));
    WITH sysTime^ DO
        userData := DateTime {tm_year + 1900, tm_mon + 1, tm_mday, tm_hour, tm_min, tm_sec, 0, tm_gmtoff / 60, tm_isdst <> 0};
    END(*WITH*);
END GetClock;
 
PROCEDURE SetClock (userData: DateTime);
  (* Sets the system clock to the given local date and time *)
(*
 *    VAR
 *        sysTime: DateTimeRec;
 *    BEGIN
 *        WITH userData DO
 *            IF IsValidDateTime (userData) AND
 *               (hour <= 23) AND (minute <= 59) AND (second <= 59)
 *            THEN
 *                sysTime := DateTimeRec {year, month, day, hour, minute, second, 0};
 *                SetTime (sysTime);
 *            END(*IF*);
 *        END(*WITH*);
 *)
END SetClock;
 
END SysClock.


Regards,
Andreas
 


Gaius Mulley wrote:

Iztok Kobal <address@hidden> writes:

  

Contents of SysClock.def reveals that something is really wrong:

...snip...

CONST
  maxSecondParts = <implementation-defined integral value>;

...snap...


What to do ?
    

Hi Iztok,

ahh yes this module has not been implemented yet.  Currently the
completed iso modules are:

ChanConsts CharClass ClientSocket ConvTypes EXCEPTIONS IOChan IOConsts
IOLink M2EXCEPTION M2RTS ProgramArgs RawIO RealConv RealMath RndFile
RTdata RTentity RTfio RTgen RTgenif RTio SimpleCipher SeqFile StdChans
Storage StreamFile Strings STextIO SYSTEM TERMINATION TextIO WholeConv
WholeIO WholeStr.

There is a known problem with REAL input/output at present - which I'm
working on.  The list of finished iso modules is held in
gm2/gm2-libs-iso/README.texi

regards,
Gaius


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________________________________________________________________________
ETH Zurich
Prof. Dr. Andreas Fischlin
Systems Ecology - Institute of Integrative Biology
CHN E 21.1
Universitaetstrasse 16
8092 Zurich
SWITZERLAND

address@hidden
www.sysecol.ethz.ch

+41 44 633-6090 phone
+41 44 633-1136 fax

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