Hi Alex, Thank you for the descriptions.
Regards, Andras > On 2020. Nov 10., at 12:49, Alexander Burger <a...@software-lab.de> wrote: > > Hi Andras, > >> I would like to ask some questions on Pil21 features. >> It is enough if you points to some examples where I could dig into the >> details... > > These are indeed very good questions! Thanks that you ask, they need to be > clarified. > > >> - What is special in the ‘priv’ namespace handling? >> pil64 used it to store (private) symbols. > > I noticed that the way pil64 implemented the 'private' function was not good. > > It created a normal namespace 'priv' on-the-fly, interned the given symbols > into > that namespace, and then put 'priv' as the *second* namespace in the search > order: > > : (private) foo # Intern 'foo' in 'priv' > > : (symbols) # Search order > -> (pico priv) > > So now 'foo' is indeed private. The problem is that *if' another symbol named > "foo" exists in 'pico', it overshadoes the 'foo' in 'priv', and this is not > what > is expected for a private symbol. > > > Pil21 implements a special handling for 'priv'. Now 'priv' is part of the > interpreter core, and behaves a little different from normal namespaces. > > : (private) foo # Intern 'foo' in 'priv' > > : (symbols) # Search order > -> (pico) > > : (all 'priv) > -> (priv~foo) > > 'priv' is not put into the search order at all, but internally it is always > searched first. That way it will not be overridden by symbols with the same > names in 'pico', but still *new* symbols will be interned in 'pico'. > > >> - What is the purpose of the ‘~’ marker in the namespaces? > > This is only used for error checking: To check in 'symbols' that the arguments > are really namespaces, and that 'nsp' in 'nsp~foo' is OK. > > >> - What does it mean, that map functions accept atomic arguments? >> It is not required to pass lists as arguments? >> Atomic arguments are handled as 1-item lists or infinite lists with the >> same item? > > Yes, the latter. > > In pil32 and pil64 you could call > > : (mapcar * (1 2 3 4 5 6) (2 .)) > -> (2 4 6 8 10 12) > > i.e. supply an infinite list of 2's. > > Now in pil21 you can simply call > > : (mapcar * (1 2 3 4 5 6) 2) > > This is especially useful if '2' is not a constant, e.g. > > (mapcar * Lst Factor) > > In pil64 you would need to build the circular list explicitly: > > (mapcar * Lst (circ Factor)) > > ☺/ A!ex > > -- > UNSUBSCRIBE: mailto:picolisp@software-lab.de?subject=Unsubscribe -- UNSUBSCRIBE: mailto:picolisp@software-lab.de?subject=Unsubscribe
