On Tue, Feb 07, 2017 at 06:44:43AM -0800, Lindsay John Lawrence wrote:
>((= '() Lst) '() )
> ..
> However when I (pp 'selectN) it wrote the line where I am trying to test
>((= 'NIL Lst) 'NIL)
Yes, the reader returs the symbol NIL when it sees ()
> Is that correct? Shouldn't the pp outp
I just noticed... my original source for the selectN function is this...
(de selectN (Lst P)
..
((= '() Lst) '() )
..
However when I (pp 'selectN) it wrote the line where I am trying to test
for an empty list as
(de selectN (Lst P)
..
((= 'NIL Lst) 'NIL)
..
Is that correct? Shouldn't the
Thanks!
I still trip over those nuances if I don't pay attention testing for
NIL or '(), or not, in lists and symbols.
/Lindsay
On Mon, Feb 6, 2017 at 11:13 PM, Alexander Burger
wrote:
> On Tue, Feb 07, 2017 at 07:41:45AM +0100, Alexander Burger wrote:
> > (cond
> >
Thanks Alex!
recur/recurse... I hadn't noticed those functions in the picolisp function
library until now. Very useful.
/Lindsay
On Mon, Feb 6, 2017 at 10:41 PM, Alexander Burger
wrote:
> Hi Lindsay,
>
> > I couldn't resist tinkering with this a bit more.
>
> Many thanks for this and all the
Hi Jon,
> I wasn’t aware of nor, nand, nond. Maybe there should have been a few more
> “See also” in the docs.
True! I've added some ...
♪♫ Alex
--
UNSUBSCRIBE: mailto:picolisp@software-lab.de?subject=Unsubscribe
Wow...really pleased I asked. Those are great examples and I'm sure I'll
learn a lot from them. I've needed to process lists/trees most of
programming "life" and the languages I've used haven't exactly regarded
them as first class citizens and this has slowed me down quite a lot. I
don't have that
Hi,
I wasn’t aware of nor, nand, nond. Maybe there should have been a few more “See
also” in the docs.
/Jon
> On 7. Feb, 2017, at 08:31, Alexander Burger wrote:
>
> On Tue, Feb 07, 2017 at 08:13:06AM +0100, Alexander Burger wrote:
>> Better to use (not Lst).
>
> One more note: I even try to
On Tue, Feb 07, 2017 at 08:13:06AM +0100, Alexander Burger wrote:
> Better to use (not Lst).
One more note: I even try to avoid 'not' whenever possible, as it is an
additional function call overhead.
It is often possible to use the complementary flow function,
like (ifn Lst ..) instead of (if (no
On Tue, Feb 07, 2017 at 07:41:45AM +0100, Alexander Burger wrote:
> (cond
>((= 'NIL Lst) 'NIL)
One important note: (= 'NIL Lst) is not a good idea.
Better to use (not Lst).
(= NIL Lst) would compare *names* if 'Lst' happened to be
a symbol, so (= NIL "NIL") returns T.
Hi Lindsay,
> I couldn't resist tinkering with this a bit more.
Many thanks for this and all the previous examples!
> # --
> (de selectN (Lst P)
>(let selectNN
> '((Lst P I)
> (cond
> ((= 'NIL Lst) 'NIL)
>
I couldn't resist tinkering with this a bit more.
# --
(de selectN (Lst P)
(let selectNN
'((Lst P I)
(cond
((= 'NIL Lst) 'NIL)
((P (car Lst) I)
(cons
(car Lst)
Once I started to get the hang of the basic building blocks, I started
seeing patterns and ways to build on what I had written before
e.g. To me, the next logical development of dropN, pickN is to allow
providing a predicate function... effectively making it a general purpose
list filter
#
All of those problems are fun to explore... try writing different versions
of the selected solutions, iterative vs recursive, using just basic list
building block functions vs the wonderfully convenient functions that
picolisp provides, etc
This particular one piqued my interest enough to try writ
I just came back to say I just looked and didn't realise I had to click P16
to see that function
Thanks once again.
Just goes to show...however idiot-proof you make your system
someone will just invent a better idiot :)
On 6 February 2017 at 22:51, dean wrote:
> Oh gosh...I missed that c
Oh gosh...I missed that completely...Thanks Lindsay...That explains
everything!
I'm really pleased you told me that because drop looks like a really useful
function.
Best Regards
Dean
On 6 February 2017 at 22:27, Lindsay John Lawrence <
lawrence.lindsayj...@gmail.com> wrote:
> P16 (**) Drop every
P16 (**) Drop every N’th element from a list.
(de drop (Lst N)
(make
(for (I . X) Lst
(unless (=0 (% I N))
(link X) ) ) ) )
: (drop ’(a b c d e f g h i k) 3)
-> (a b d e g h k)
'drop' is the function given as a solution to the problem.
/Lindsay
On Mon, Feb 6, 2017 at 1:24 PM
Hi Alex
: (filter prog2 (1 a 2 b 3 c) '(T NIL .))
-> (1 2 3)
: (filter prog2 (1 a 2 b 3 c) '(NIL T .))
-> (a b c)
Yes the above is exactly what I'm after.
I copied this drop example straight from ninety nine
? P16 (**) Drop every N'th element from a list.
: (drop '(a b c d e f g h
On Mon, Feb 06, 2017 at 12:25:14PM +0100, Alexander Burger wrote:
> > I'd like to split a list '(txt1 2 txt2 6
> > into 2 lists
> > '(txt1 txt2...
> > and
> > '(2 6
>
> You could for example filter them:
>
>(let
> (Lst '(txt1 2 txt2 6)
> A (filter sym? Lst)
> B (fi
Hi Dean,
> I'd like to split a list '(txt1 2 txt2 6
> into 2 lists
> '(txt1 txt2...
> and
> '(2 6
You could for example filter them:
(let
(Lst '(txt1 2 txt2 6)
A (filter sym? Lst)
B (filter num? Lst) )
... use A and B ...)
> I found drop (in ninety nine...
Hi
I'd like to split a list '(txt1 2 txt2 6
into 2 lists
'(txt1 txt2...
and
'(2 6
I found drop (in ninety nine...) which looks ideal but it's apparently
undefined in pil64.
I've looked for something similar but it's not jumping out :)
Any help much appreciated.
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