Wolfram Language Paclet Repository
Community-contributed installable additions to the Wolfram Language
JasonB`WeakCache`
CleanupAfter |
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Details and Options
Examples
(3)
Basic Examples
(2)
As in many examples for this paclet, we set the evaluation history to zero to avoid confusion:
In[1]:=
$HistoryLength=0;expr=RandomGraph[{4,5}];
[expr,Print["Cleaning up after expr"]]
 | CleanupAfter |
When clearing the expression the cleanup function is called:
In[2]:=
expr=.
Cleaning up after expr
Cleanup functions apply to particular instances of expressions:
In[3]:=
| CleanupAfter |
| CleanupAfter |
Out[3]=
True
In[4]:=
expr2=.
expr2 deleted
In[5]:=
expr1=.
expr1 deleted
In the above example the two expressions were SameQ but not SameInstanceQ. In the following example expr1 and expr2 both point to the same expression instance:
In[6]:=
| CleanupAfter |
| CleanupAfter |
| SameInstanceQ |
Out[6]=
True
Both of the added cleanup functions will be called when all references to the data are gone:
In[7]:=
expr1=.
In[8]:=
expr2=.
expr1 deleted
expr2 deleted
Set the history length to the default value and evaluate the same code as above:
In[1]:=
$HistoryLength=∞;g=RandomGraph[{4,5}]
Out[1]=
In[2]:=
| CleanupAfter |
Clearing the symbol g does not remove all references to the object:
In[3]:=
g=.
The value associated with g is still stored in the history:
In[4]:=
%%%
Out[4]=
Only by clearing the history is the memory freed:
In[5]:=
| ClearHistory |
g has been cleared
Applications
(1)
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