Re: Example of sets and indexing

[Marcus G. Daniels]

>>>>> "AV" == Ajoy Victor <address@hidden> writes:

AV> How is this used?

AV> createIndex: aZone fromMember: anObject

It can be used in the situation where you have a collection that
has the notion of keys and values. 

See below for an example of createIndex:fromMember: and its use with
Lists where members objects store the links (thus ensuring unique
members and the notion of a `set').  Compare the two code sections
within the "#if 1" area -- they are functionally equivalent.

AV> What messages are commonly used between createBegin and CreateEnd?

Generally, any message that describes structural characteristics
of the object you are creating.  For example, a Map *must* be able to
compare one key with another, or it has no meaningful semantics
(-setCompareFunction:).

AV> What kind of messages are commonly used to manipulate sets?

add:, replace:, contains:, or getCount:.

AV> I think I'm going to need a set of objects where each contains a
AV> 2D grid Is that possible?

How about using the Discrete2d interface in the space library?

AV> I can't even program this: (What is wrong?)

Remember to include simtools.h. and call initSwarm. 

A couple portability suggestions: 1) include misc.h instead of stdio.h.
Directly including a system header will make your model less portable.
2) note that `unsigned char' is not the same size as an `id'.
I suggest a double cast so that it is clear in the code that this
was not an oversight.

   [s add: (id) (unsigned) i];

You're right about count vs. getCount; getCount should have worked;
that was a bug in 1.4.1.

#import <simtools.h>
#import <collections.h>
#import <defobj/Create.h>

#import <collections/Collection.h>

@interface Integer: CreateDrop
{
  int value;
  member_t link;
}
- setValue: (int)value;
- (int)getValue;
@end

@implementation Integer
- setValue: (int)theValue
{
  value = theValue;
  return self;
}

- (int)getValue
{
  return value;
}

- (void)describe: outputCharStream
{
  char buf[DSIZE (int) + 1 + 1];

  sprintf (buf, "%d\n", value);
  [outputCharStream catC: buf];
}
@end

#define MAKEINTEGER(aZone,value) \
  [[[Integer createBegin: aZone] setValue: value] createEnd]
  
int 
main (int argc, const char **argv)
{
  
  initSwarmBatch (argc, argv);
  
  {
    id <Zone> aZone = [Zone create: globalZone];
    id member;
    id <Index> index;

#if 1
    id l;

    l = [List createBegin: aZone];
    [l setIndexFromMemberLoc: offsetof (Integer, link)];
    l = [l createEnd];
    
    [l addLast: MAKEINTEGER (aZone, 10)];
    member = MAKEINTEGER (aZone, 20);
    [l addLast: member];
    index = [l createIndex: aZone fromMember: member];
    [l addLast: MAKEINTEGER (aZone, 30)];
#else
    id s;

    s = [OrderedSet createBegin: aZone];
    [s setIndexFromMemberLoc: offsetof (Integer, link)];
    s = [s createEnd];

    [s add: MAKEINTEGER (aZone, 10)];
    member = MAKEINTEGER (aZone, 20);
    [s add: member];
    index = [s createIndex: aZone fromMember: member];
    [s add: MAKEINTEGER (aZone, 30)];
#endif
    do xprint (member); while (member = [index next]);
  }
}

/*
Local Variables:
compile-command: "/opt/src/mgd/packages/swarm/swarm/bin/libtool-swarm 
--mode=link /opt/src/mgd/packages/development/egcs/bin/gcc -o memberloc -g 
-Wno-import -I/opt/src/mgd/packages/swarm/swarm/include 
-L/opt/src/mgd/packages/swarm/swarm/lib memberloc.m -lswarm -lobjc"
End:
*/

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