> On 08 Jun 2016, at 10:40, Henrik Johansen <henrik.s.johan...@veloxit.no> > wrote: > > >> On 04 Jun 2016, at 9:13 , stepharo <steph...@free.fr> wrote: >> >> >> >> Le 3/6/16 à 19:16, Esteban A. Maringolo a écrit : >>> Regarding the first part of your email, about UI lockups, it is almost >>> unavoidable, because in Pharo almost everything happens in the main >>> thread, as you pointed out. >> Yes. This is all my point. > > IMHO, all Pharo beginner tutorials should start by showing off Cmd - dot (or > Alt - dot, on Win / Linux). > > Not just because it's cool, but because it's necessary :) > > Cheers, > Henry
Very true. Yet, and I have already mentioned this years ago, it is technically totally possible to properly detect massive stack growth, before things get out of control. Sadly, VM people think this is not needed (or too costly). Consider the following in Common Lisp (LispWorks): CL-USER 1 > (defun fac (n) (if (< n 2) 1 (* n (fac (1- n))))) FAC CL-USER 2 > (fac 5) 120 CL-USER 3 > (fac 100) 93326215443944152681699238856266700490715968264381621468592963895217599993229915608941463976156518286253697920827223758251185210916864000000000000000000000000 CL-USER 4 > (fac 400) Stack overflow (stack size 31744). 1 (continue) Extend stack by 50%. 2 (abort) Return to level 0. 3 Return to top loop level 0. Type :b for backtrace or :c <option number> to proceed. Type :bug-form "<subject>" for a bug report template or :? for other options. CL-USER 5 : 1 > :c 1 Stack overflow (stack size 48128). 1 (continue) Extend stack by 50%. 2 (abort) Return to level 0. 3 Return to top loop level 0. Type :b for backtrace or :c <option number> to proceed. Type :bug-form "<subject>" for a bug report template or :? for other options. CL-USER 6 : 1 > :c 1 64034522846623895262347970319503005850702583026002959458684445942802397169186831436278478647463264676294350575035856810848298162883517435228961988646802997937341654150838162426461942352307046244325015114448670890662773914918117331955996440709549671345290477020322434911210797593280795101545372667251627877890009349763765710326350331533965349868386831339352024373788157786791506311858702618270169819740062983025308591298346162272304558339520759611505302236086810433297255194852674432232438669948422404232599805551610635942376961399231917134063858996537970147827206606320217379472010321356624613809077942304597360699567595836096158715129913822286578579549361617654480453222007825818400848436415591229454275384803558374518022675900061399560145595206127211192918105032491008000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000 CL-USER 7 > (defun infinite () (cons 'a (infinite))) INFINIT CL-USER 8 > (infinite) Stack overflow (stack size 80896). 1 (continue) Extend stack by 50%. 2 (abort) Return to level 0. 3 Return to top loop level 0. Type :b for backtrace or :c <option number> to proceed. Type :bug-form "<subject>" for a bug report template or :? for other options. CL-USER 9 : 1 > :a CL-USER 10 > Just having an upper limit to the stack catches 99% of infinite loops - that would be nice to have. This has existed for 10s of years AFAIK. Sven PS: Of course, the stack size can be set larger to begin with, if necessary. I believe it is even per execution thread.
