8

Consider the following example:

In[1]:= f[x_]:=x+1;g[x_]:=f[2x]

In[2]:= TracePrint[g[1]]
 g[1]
  g
  1
 f[2 1]
  f
  2 1
   Times
   2
   1
  2
 f[2]
 2 + 1
  Plus
  2
  1
 3

Out[2]= 3

So far, so good. However I'd now like to instruct TracePrint to treat evaluation of f as atomic, that is not to print the intermediate steps of evaluating f[2], so that the next line after f[2] would be 3 (but without excluding any other lines). My first idea was to just make f read protected:

In[3]:= SetAttributes[f,ReadProtected]

In[4]:= TracePrint[g[1]]
 g[1]
  g
  1
 f[2 1]
  f
  2 1
   Times
   2
   1
  2
 f[2]
 2 + 1
  Plus
  2
  1
 3

Out[4]= 3

As you can see, the inner working of f is still traced. However the attribute is otherwise honoured:

In[5]:= ?f
Global`f

Attributes[f] = {ReadProtected}

Another thing which does not work is

TracePrint[g[1],Except[_f]]

which again gives the complete trace.

So how do I instruct TracePrint to treat the function f as atomic?

celtschk
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1 Answers1

8

Maybe 

  TracePrint[g[1], TraceOff -> f]

?

kglr
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    They should really mention that option on the TracePrint help page! – celtschk Apr 17 '12 at 09:52
  • @celtschk, couldn't agree more. – kglr Apr 17 '12 at 09:53
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    @celtschk The documentation of Trace has a whole list of options. The documentation of TracePrint says (among other things): "TracePrint does not support the TraceBackward option of Trace." which (rather vaguely, I agree) implies other options of Trace should work. See also this tracing overview – Sjoerd C. de Vries Apr 17 '12 at 10:51
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    Don't forget TraceInternal a boolean flag (previously documented, but not anymore) which will allow tracing into the internal functions not normally traceable. – rcollyer Apr 24 '12 at 02:36