I’m getting the following error:
sheet.rb:35:in values': stack level too deep (SystemStackError) from sheet.rb:35:invalues’
from sheet.rb:53:in to_s' from sheet.rb:52:into_s’
from sheet.rb:52:in map' from sheet.rb:52:into_s’
from sheet.rb:52:in to_s' from sheet.rb:52:inmap’
from sheet.rb:52:in to_s' from sheet.rb:52:into_s’
from sheet.rb:52:in map' from sheet.rb:52:into_s’
from sheet.rb:92
The output above is given in full. Is Ruby truncating the call stack
in this output? If so, how I can I see a larger snapshot of the stack,
so I can trace down where the infinite recursion is really happening? If
not, why am I getting this error?
Thanks,
Ken
Kenneth McDonald wrote:
from sheet.rb:52:in `to_s'
from sheet.rb:52:in `to_s'
from sheet.rb:52:in `map'
from sheet.rb:52:in `to_s'
from sheet.rb:92
The output above is given in full. Is Ruby truncating the call stack
in this output? If so, how I can I see a larger snapshot of the stack,
so I can trace down where the infinite recursion is really happening? If
not, why am I getting this error?
Here’s one even shorter:
def x; x; end; x
SystemStackError: stack level too deep
from (irb):2:in x' from (irb):2:inx’
from (irb):4
Pretty smart of ruby to avoid a gazillion lines of identical output IMHO
Daniel
Daniel DeLorme wrote:
Kenneth McDonald wrote:
I’m getting the following error:
sheet.rb:35:in values': stack level too deep (SystemStackError) from sheet.rb:35:invalues’
/* SNIP */
SystemStackError: stack level too deep
from (irb):2:in x' from (irb):2:inx’
from (irb):4
Pretty smart of ruby to avoid a gazillion lines of identical output IMHO
Daniel
It’s nice to see a smart little gem in them thar rubies 
I remmeber how long it took for a C Program to crash from the number of
function calls… Dang thats a good Ruby.
TerryP.
Daniel DeLorme wrote:
from sheet.rb:52:in `map'
To a newcomer, it’s sorta nonobvious, however–it turned out the problem
was that I’d made a circular reference to ‘values’ instead of ‘@values’,
and the fact that the stack was full of ‘values’ frames is certainly not
obvious from the above.
Ken
On Fri, 2007-31-08 at 10:35 +0900, Kenneth McDonald wrote:
To a newcomer, it’s sorta nonobvious, however–it turned out the problem
was that I’d made a circular reference to ‘values’ instead of ‘@values’,
and the fact that the stack was full of ‘values’ frames is certainly not
obvious from the above.
A good rule of thumb for avoiding this problem is to name your classes
and your variables after nouns and your methods after verbs.
So instead of having a method “values” that uses the member “@values” –
something pretty much guaranteed to lead to trauma at some point down
the road – make a method “get_values” or “set_values” or
“initialize_values” or whatever that uses a member called @values.
Heh, This is one of the few languages I haven’t had that happen to to
me on before.
Lisp, C, C++, Perl… but I haven’t caused one of those on ruby
before.
Now, if you’ve really intended to do recursion, try making it tail
recursive.
Err… Ruby does optimize for tail recursion, right?
–Kyle
On 31.08.2007 03:54, Michael T. Richter wrote:
something pretty much guaranteed to lead to trauma at some point down
the road – make a method “get_values” or “set_values” or
“initialize_values” or whatever that uses a member called @values.
Although I agree in general (i.e. using verbs for method names) I
heavily disagree with your last advice: according to Ruby’s convention a
getter is named “foo” and a setter “foo=”. This is implemented in attr*
methods and IMHO it is not advisable to leave this convention.
Also, there are good reasons to use getters instead of instance
variables, namely that you get more abstraction (there doesn’t
necessarily have to be a member variable of that name).
Kind regards
robert
On 8/31/07, Kyle S. [email protected] wrote:
Heh, This is one of the few languages I haven’t had that happen to to
me on before.
Lisp, C, C++, Perl… but I haven’t caused one of those on ruby before.
Now, if you’ve really intended to do recursion, try making it tail recursive.
Err… Ruby does optimize for tail recursion, right?
I’m not sure, after some googling it seems that 1.8 doesn’t and YARV
might partially optimize.
Unless I read otherwise, I usually assume that languages don’t optimize
tail recursion. If you look at typical codebases, using tail recursion
instead of some sort of higher-level looping construct, or even a simple
basic loop, is really an academic curiosity. It doesn’t normally make
code clearer or easier to write, and most people, even those who are
aware of it, don’t use it. (In fact people who really know about it
often tend to avoid it because they also know of the overhead induced by
function calling.) So why bother optimizing for this case?
Ken