[R] browser/debug and for loop

[Peter Dalgaard BSA]

Vadim Ogranovich <vograno at arbitrade.com> writes:

> Dear R-Users,
> 
> It seems like once one invokes browser() inside a loop and steps through the
> body using 'n' any subsequent loop will be "intercepted" by debug()
> function. Here is exactly what I mean
> 
> # fresh R session
> # run a loop that has browser() inside the body
> > for (i in seq(5)) { browser(); print(i) }
> for (i in seq(5)) { browser(); print(i) }
> Called from: NULL
> Browse[1]> n
> n
> debug: print(i)
> Browse[1]> Q
> Q
> 
> #  remove browser(), debug() is still there
> > for (i in seq(5)) { print(i) }
> for (i in seq(5)) { print(i) }
> debug: i
> Browse[1]> Q
> Q
> 
> My guess is that when I was stepping through some function got flagged for
> debugging. I tried to undebug "for", but that didn't work.
> 
> This is R.1.5.0 on RedHat Linux 7.1
> 
> Any suggestion will be appreciated.

The effect is still there in 1.6.0pre. However, it doesn't seem to be
"for" that got the debug flag set, but "{":

> {i}
debug: i
Browse[1]> 
[1] 4

I can't think of an immediate workaround except: "just don't do
that"...

-- 
   O__  ---- Peter Dalgaard             Blegdamsvej 3  
  c/ /'_ --- Dept. of Biostatistics     2200 Cph. N   
 (*) \(*) -- University of Copenhagen   Denmark      Ph: (+45) 35327918
~~~~~~~~~~ - (p.dalgaard at biostat.ku.dk)             FAX: (+45) 35327907
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