Re: Questions on PARI/GP formatting

[Bill Allombert <Bill.Allombert@math.u-bordeaux.fr>]

On Tue, Sep 05, 2023 at 09:24:02PM +0200, hermann@stamm-wilbrandt.de wrote:
> On 2023-09-05 18:22, Bill Allombert wrote:
> > We offer this tutorial:
> > 
> > <https://pari.math.u-bordeaux.fr/Events/PARI2019b/talks/prog.pdf>
> > 
> Thanks, looks good.
> 
> > > I added whitespace where it helped me, but overall it is not
> > > consistent.
> > > Are there best practices wrt GP optional whitespace use?
> > > 
> Examples seem to indicate mostly not to use optional whitespace.

GP ignores whitespaces anyway, so feel free to pick the whitespace
policy you prefer.
 
> > > I use "break", should it be "break()" instead?
> > 
> > Yes, because break has an optional argument.
> > 
> I added "()" to my script breaks -- tutorial example on page 8 misses "()"
> as well.

I did that due to vertical space constraint (I would have needed to add a
newline to avoid the difficult to read 'break()));' ).

> I changed my gist, should now look mostly like the examples in tutorial:
> https://gist.github.com/Hermann-SW/50514eaf06b4d91ec6bcee5e49732dff
> 
> 
> Few followup questions:
> 
> 1)
> I cannot put "my()" in first line of function, because in some cases need to
> break() before.
> Is that OK?

Sure.

> 2)
> Multi assignment seems to work in "my()", is that OK?
> ...
> test(v)=
> {
>   if(#v<4,
>     break());
>   my([l,n,p,q]=v,pnr,qnr,sqrtm1);
> ...

Sure.

> 3)
> Variable "n" is not used, but needed for multi assignment to work.
> Are there anonymous variables to indicate that?

No, but you can omit n:
my([l,,p,q]=v,pnr,qnr,sqrtm1);

> 4)
> "for*" loops work multiline only inside "{...}".
> I had to put braces around last loop calling "test()" to get multiline
> foreach working.
> Is that OK?
> 
> ...
> };
> 
> {
>   foreach(rsa,v,
>     test(v));
> }

Sure!

Cheers,
Bill