Ilya Zakharevich on Wed, 13 Dec 2023 00:12:46 +0100


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Re: The GP command “?”


On Sun, Dec 10, 2023 at 12:12:36PM +0100, Bill Allombert wrote:
> On Sat, Dec 09, 2023 at 07:49:50PM -0800, Ilya Zakharevich wrote:
> > Are people ACTUALLY using “the sections” in the results of the GP command
> >      ?
> > ?  Myself, I use only “the tail” of its output.  I do not ever recall
> > finding what ?1 outputs useful in the slightest…
> 
> The start of the list is more for beginner, the end more for advanced users.

I repeat: I could NEVER get anything important for a beginner “from
the list of sections”.

Just imagine some REAL guy you know (not a spherical cow in vacuum).
Assume that she is a beginner in GP/PARI.  Doing ?1 emits a list of 80
super-obscure words — without any comment.  What a REAL GUY would do
in such a situation?!

  (YES, I observed several REAL people doing exactly this — under my
   guidance.  I needed to be VERY apologetic…)

And do not forget that many of these obscure words are
misnomers. — Like the discussion of serreverse() etc. earlier.  (Or
the function returning log(gamma()) — you cannot find it even by name
using TAB:
    log<TAB>
.) 

> > (However, the output of ?19, ?20, ?21 is quite useful (although	these is
> > NOT LISTED in the output of
> >       ?
> 
> ?19, ?20, ?21 list functions that are private to the GP interpreter and cannot
> be called normally.

Of course they can — you just need to know how.  For example, PARI can
happily do

  35 \/ 23

After you realized this, these lists are much more important than what
?n returns.

Hope this helps,
Ilya