Date:         Wed, 6 Jul 2005 20:24:15 -0700
Reply-To:     John McQuown <John.McQuown@OTNNET.COM>
Sender:       "SAS(r) Discussion" <SAS-L@LISTSERV.UGA.EDU>
From:         John McQuown <John.McQuown@OTNNET.COM>
Subject:      Re: SUGGESTION: Allow temporary array element as iterative DO
              index              variable.
Comments: To: Jack Hamilton <jfh@STANFORDALUMNI.ORG>
Content-Type: text/plain; charset="us-ascii"

I think it is because the temporary variable is not in the permanent
variable list and not subject to all the overhead that SAS provides for
managing permanent variables.

For example, see the first and second variations of your demo, below.
You can track these memory usage differences if you turn on OPTIONS
FULLSTIMER;

Cheers, john

1109  options fullstimer;
1110
1111  data _null_;
1112      array x{1} x1 (3);
1113      do i = 1 to x{1};
1114          put 'hi!';
1115      end;
1116  run;
hi!
hi!
hi!
NOTE: DATA statement used:
      real time           0.00 seconds
      user cpu time       0.00 seconds
      system cpu time     0.00 seconds
      Memory                            104k
1117
1118  data _null_;
1119      array x{1} _temporary_;
1120      x{1} = 3;
1121      do i = 1 to x{1};
1122          put 'hi!';
1123      end;
1124  run;
hi!
hi!
hi!
NOTE: DATA statement used:
      real time           0.01 seconds
      user cpu time       0.01 seconds
      system cpu time     0.00 seconds
      Memory                            88k
1125
1126  data _null_;
1127      array x{1} _temporary_;
NOTE: SCL source line.
1128      do x{1} = 1 to 3;
              -
              73
              76
ERROR 73-322: Expecting an =.
ERROR 76-322: Syntax error, statement will be ignored.
1129          put 'hi!';
1130      end;
1131  run;
NOTE: The SAS System stopped processing this step because of errors.
NOTE: DATA statement used:
      real time           0.00 seconds
      user cpu time       0.00 seconds
      system cpu time     0.00 seconds
      Memory                            34k


-----Original Message-----
From: SAS(r) Discussion [mailto:SAS-L@LISTSERV.UGA.EDU] On Behalf Of
Jack Hamilton
Sent: Wednesday, July 06, 2005 8:00 PM
To: SAS-L@LISTSERV.UGA.EDU
Subject: SUGGESTION: Allow temporary array element as iterative DO index
variable.

I can't think of a good reason why this should be allowed:

=====
1    data _null_;
2       array x[1] _temporary_;
3       x[1] = 3;
4       do i = 1 to x[1];
5          put 'hi!';
6       end;
7    run;

hi!
hi!
hi!
NOTE: DATA statement used (Total process time):
      real time           0.28 seconds
      cpu time            0.06 seconds
=====

but not this:

=====
8
9    data _null_;
10      array x[1] _temporary_;
11      do x[1] = 1 to 3;
            -
            73
            76
ERROR 73-322: Expecting an =.

ERROR 76-322: Syntax error, statement will be ignored.

12         put 'hi!';
13      end;
14   run;

NOTE: The SAS System stopped processing this step because of errors.
NOTE: DATA statement used (Total process time):
      real time           0.07 seconds
      cpu time            0.00 seconds
=====


--
Jack Hamilton
Sacramento, California