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Stack
Stack[
] shows the current evaluation stack, giving a list of the tags associated with evaluations that are currently being done.
Stack[
pattern
] gives a list of expressions currently being evaluated which match the pattern.
Stack[_] shows all expressions currently being evaluated.
You can call Stack from inside a dialog to see how the dialog was reached.
In the list returned by Stack[
pattern
], each expression is wrapped with HoldForm.
The maximum length of Stack[
] is limited by $RecursionLimit.
Stack has attribute HoldFirst.
See the Mathematica book: Section 2.5.11.
See also: Trace.
Further Examples
Stack[_] gives the expressions that are being evaluated at the time when it is called, in this case including the Print function.
In[1]:= 
{f[g[Print[Stack[_]]]]; , f[g[Print[Stack[_]]]], g[Print[Stack[_]]], Print[Stack[_]]}
Stack gives the tags associated with the evaluations that are being done when it is called.
In[2]:= 
{CompoundExpression, f, g, Print}
Here is the standard recursive definition of the factorial function.
In[3]:= 
This evaluates fac[10], starting a dialog when it encounters fac[4].
In[4]:= 
TraceDialog::dgbgn: Entering Dialog; use Return[] to exit.
Out[5]= 
This shows what objects were being evaluated when the dialog was started.
In[6]:= 
Out[6]= 
This ends the dialog.
In[7]:= 
TraceDialog::dgend: Exiting Dialog.
Out[4]= 
StackInhibit prevents Print from being included on the stack.
In[5]:= 
{CompoundExpression, f, g}
StackBegin[
expr
] uses a fresh stack in the evaluation of expr.
In[6]:= 
{g, h}
Out[6]= 
THIS IS DOCUMENTATION FOR AN OBSOLETE PRODUCT. SEE THE DOCUMENTATION CENTER FOR THE LATEST INFORMATION. | |
