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silent option in nested calls to try()

4 messages · Thomas Petzoldt, Luke Tierney

Original
Thomas Petzoldt
# 
Hello,

is it *really intentional* that the "silent" option of try() does only 
apply to the outer call in nested try constructs? I would assume that a 
silent try() should suppress all error messages regardless where they 
occur, even if they are already handled with other try()'s.

The error message itself should be (and is in both cases) reported by 
the return value of try().

Thanks in advance

Thomas


## Old behavior (tested with R-2.4.1):
 >  try(try(exp(NULL)), silent=TRUE)
 >


## Current behavior (R-2.6.0 unstable, build 42641, WinXP):
 >  try(try(exp(NULL)), silent=TRUE)
Error in exp(NULL) : Non-numeric argument to mathematical function
 >
Luke Tierney
# 
Yes.  If you want finer control use tryCatch.

Best,

luke
On Mon, 27 Aug 2007, Thomas Petzoldt wrote:

            

      
      
      
    

        

  
    

      
      
    

  


  


      

    

    

      
      

        


  

        

      Thomas Petzoldt
    

    

      
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Dear Luke,

thank you very much for your immediate answer. The problem I see is, 
however, that while one can rewrite ones outer code using tryCatch, one 
may not have control over the use of try in a given inner function.

Thomas

        
Luke Tierney wrote:

            

      
      
      
    

  
  


  


      

    

    

      
      

        


  

        

      Luke Tierney
    

    

      
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Your best option is to contact the author of the software and ask them
to use silent = TRUE or try to play some games with output capture.

try() is an old interface that has been reimplemented on top of
tryCatch.  It could be modified to, for example, use message(), which
would then allow messages to be suppressed with suppressMessages, but
this leaves the issue of warnings (see the try() code).  Coming up
with something that behaves sensibly would require a considerable
design effort.  I don't see the effort as warranted at this point.

The choice of silent=TRUE as the default is I believe unfortunate but
it has been so for many years.  Again I don't see the effort in
changing this as warranted at this point.

Best,

luke

        
On Mon, 27 Aug 2007, Thomas Petzoldt wrote: