Sorry that's too complicated for me, TL;DR

> I have to understand what (LIST) means in the documentation.

According to the docs cited in

List's terminology and Parentheses in Perl

<updated>

Uppercase "LIST" in perldocs is a argument placeholder for any code ...

• compiled in "list context"
• delivering a "list value" at run time

For instance from the docs for print ...

print LIST; means that ...

• print 1,2,3;

  the two commas are compiled to create a "list value" 1,2,3 for print

• print @a;

  the array @a will be compiled to pass it's content as "list value" ( i.e.not his length from scalar context)

• print func();

  the sub &func will be called in "list context" at run time and return a "list value" from it's last statement. ( compare wantarray )

</updated>

> To understand this:

> > The scalar comma operator returns the last element.

> I must understand in which list it is the last element.

Comma separated lists (sic)

Please compare (updated)

# --- list assignments
@a   = (1,2,3); # list comma
@a   = (1..3);  # list range
($a) = @a;      # deconstruction => $a==1 

# --- scalar assignments
$a = (1,2,3);   # scalar comma
$a = (1..3);    # flip flop operator ... Oo oops!
$a = @a;        # scalar @a == length
[download]

The parens on RHS only do grouping here they do not create a list. Hence the context is propagated to the operators , and ..

@a = and (...)= are "list assignment" imposing "list context".

The range 1..3 returns the list value 1,2,3 in list context only.

You have to think of the whole statement as an op-tree...

• propagating context down
• passing "values" up

With ...

• operators changed by upper context
• operators (sometimes) creating down context

If that's not clear enough please show a short code exemplifying your problem.

HTH

update

you may want to play around yourself with B::Deparse and B::Concise to experiment around with the snippets shown

perl -MO=Deparse,-p -e "CODE"

and

perl -MO=Concise -e "CODE"