Hi Danilo, Your example helped. I can reason with (conc equences) now =) /Lindsay
> AFAIK there is only one empty `list' in PL, and that is `NIL'. So > after `conc'atenating to it's end it would no longer be empty. > > [de ex2 [] > [let [R [list]] > [do 10 > [conc R [list 'A]] ] > # Will have to find the end of `R' each time!! > # Even worse if `R' is `circ'ular, which will result in > infinite recursion and out of stack memory. > # In Your second implementation `'[A]' was `conc'ed to itself, > which resulted in `circ'ular list `[A .]'. > # : [setq L1 '[A]] [conc [] L1 L1] > # -> [A .] > # To avoid that it was corrected to `[list 'A]'. > (cdr R) ] ] >
