Fun with shelves.

Hi folks, 

I've noticed some very wrong looking behaviour with shelves, with v5.4 #41
running on Solaris. Below, variable Y is bound by the time it is put in the
shelf, using index 0 to set the whole shelf. Not only does shelf_get
retrieve the same argument unbound, but in the trace we can see that by the
time the call to shelf_set exits, it has managed to unbind Y! Mummy! Help!

On the bright side, there seems to be a workaround if you set the slots
individually. See further below.

cheers,

josh




ECLiPSe Constraint Logic Programming System [kernel]
Copyright Imperial College London and ICL
Certain libraries copyright Parc Technologies Ltd
GMP library copyright Free Software Foundation
Version 5.4 #41, Tue Jul 16 00:14 2002
[eclipse 1]: shelf_create(a(1, 0), X), Y = 2, shelf_set(X, 0, a(3, Y)),
shelf_get(X, 0, Z).

Y = _195
X = 'SHELF'(16'001838b8)
Z = a(3, _300)
Yes (0.00s cpu)
[eclipse 2]: trace.
Debugger switched on - creep mode
[eclipse 3]: 1.
shelf_create(a(1, 0), X), Y = 2, shelf_set(X, 0, a(3, Y)), shelf_get(X, 0,
Z).
  (1) 1 CALL  shelf_create(a(1, 0), X)   %> skip
  (1) 1 EXIT  shelf_create(a(1, 0), 'SHELF'(16'001c5ed8))   %> creep
  (2) 1 CALL  shelf_set('SHELF'(16'001c5ed8), 0, a(3, 2))   %> skip
  (2) 1 EXIT  shelf_set('SHELF'(16'001c5ed8), 0, a(3, _193))   %> creep
  (3) 1 CALL  shelf_get('SHELF'(16'001c5ed8), 0, Z)   %> skip
  (3) 1 EXIT  shelf_get('SHELF'(16'001c5ed8), 0, a(3, _600))   %> creep

Y = _193
X = 'SHELF'(16'001c5ed8)
Z = a(3, _600)
Yes (0.01s cpu)
[eclipse 4]: 


ECLiPSe Constraint Logic Programming System [kernel]
Copyright Imperial College London and ICL
Certain libraries copyright Parc Technologies Ltd
GMP library copyright Free Software Foundation
Version 5.4 #41, Tue Jul 16 00:14 2002
[eclipse 1]:  shelf_create(a(1, 0), X), Y = 2, shelf_set(X, 2, Y),
shelf_get(X, 0, Z).

Y = 2
X = 'SHELF'(16'001838b8)
Z = a(1, 2)
Yes (0.00s cpu)
[eclipse 2]: 


Developer, Parc Technologies Limited
josh.singer@parc-technologies.com
http://www.parc-technologies.com

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