Sorry, please disregard my first two questions ! The reason of my problem was that list <pi> was empty. I have discovered this finally.
Anyway sending of the problem to the list helped :) Regards, Marek Mitros [EMAIL PROTECTED] napisa³: >Hello, > >I have following questions regarding lists. > >1. Is it safe to pass lists as parameters to functions ? >2. Is it safe to return lists from functions ? > >And also additional question. > >3. Is it allowed to define sub-functions inside a function ? I have seen such >example in lib/alglie.gi - there is subfunction in RootSystem function. But >when I tried I see error. > >Regarding first 2 questions. Since assignment >a:=b; >for list do not create new list, I assume that list is really a pointer >(however this is never mentioned in GAP documentation). So if I declare local >variable in function, create list inside function and return it. Then pointer >to a list is returned but local memory of the function can be overwritten now. >So my list is not safe !? > >Here is example >create_mat:=function (n) > local i, m; > m:=[]; > for i in [1..n] do > Add(m, [i..i+n-1]); > od; > return m; >end;; > >a:= create_mat(5); ># what is it <a> now ? Is it matrix (list) or just pointer to piece of memory >which can be overwritten ? > >I am asking because I am receiving strange errors when working with matrices. >The error is saying that boolean is found where list is expected !? >For interested persons I attach my code in example.txt file. >So far everything worked OK (almost) with my matrix GAP code. > >Regards, >Marek Mitros >
_______________________________________________ Forum mailing list [email protected] http://mail.gap-system.org/mailman/listinfo/forum
