http://qs321.pair.com?node_id=1202406


in reply to [Perl 6]: Small discoveries VII, Flattening

Note the trailing comma.

Which is horribly like some Python I've had to write. I hate it when syntax DWIMs the wrong way. 

> python
>>> x = (1)
>>> x
1
>>> x = (1,)
>>> x
(1,)

[download]

So (1) is not a tuple, but (1,) is?

Back to Perl...

Does the number of trailing commas affect anything? E.g., [[["hello"],,,,],,,,]. (Because in Python it's a syntax error!)

-QM
--
Quantum Mechanics: The dreams stuff is made of

Replies are listed 'Best First'.
Re^2: [Perl 6]: Small discoveries VII, Flattening
by Anonymous Monk on Oct 31, 2017 at 14:22 UTC
    So (1) is not a tuple, but (1,) is?
    (1) is a parenthesized expression, not a tuple. Same with (1+1). This is an unfortunate result of having two different meanings for parens.
    Does the number of trailing commas affect anything?
    Consecutive commas are also a syntax error in Perl6.
[reply]
      Parens don't build lists in Perl6, commas do: 
      my @a := 1,2;
say @a.^name; #List
my @b := 1,;
say @b.^name; #List

      [download]
      Parens are usually needed because of precedence when embedding the List into another expression. The comma does have another meaning: it's the separator in argument lists.
[reply]
[d/l]
        > my $x = 1,2; say $x
1
> my $y = (1,2); say $y
(1 2)

        [download]
[reply]
[d/l]

In Section Meditations