From perlre:

+      Match 1 or more times
{n}+   Match exactly n times and give nothing back (redundant)
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I take the "redundant" annotation to mean that it is the same as:

+?     Match 1 or more times, not greedily
[download]

Though "not greedily" seems to conflict with "or more"?

chomp( $match = <DATA> );
chomp( $_ = <DATA> );

for my $regex (
        "($match){1}+",
        "($match)+",
        "($match)+?",
    ){
        print qw(FAIL SUCCESS)[ !! m/\A $regex \z/x ], "\n"
        }

__DATA__
(a|b){2}
bbab

__OUTPUT__
FAIL
SUCCESS
SUCCESS
[download]

Is it true that ($match){1}+ equals to simply $match?

Hello rsFalse,

Is it true that ($match){1}+ equals to simply $match?

Yes, and the + does nothing here, as you can see with use warnings:

Read more... (645 Bytes)

Output:

22:21 >perl 1345_SoPW.pl
Useless use of greediness modifier '+' in regex; marked by <-- HERE in
+ m/\A ((a|b){2}){1}+ <-- HERE  \z/ at 1345_SoPW.pl line 27, <DATA> li
+ne 2.
FAIL
FAIL
FAIL
SUCCESS
SUCCESS

22:21 >
[download]

Hope that helps,

Athanasius <°(((>< contra mundum

Iustus alius egestas vitae, eros Piratica,

The whole discussion is quite confusing because greediness and atomic grouping are messed up.

Could you please show a use case where you want to avoid backtracking into a once matched group (thats what atomic/possessive is about)

answering your question

> Is it true that ($match){1}+ equals to simply $match?

No!

  DB<125> $_ = "a"x5
 => "aaaaa"

  DB<126> $match = "(a+)"
 => "(a+)"

  DB<128> $_ =~ /${match}a/   
 => "aaaa"

  DB<129> $_ =~ /${match}{1}a/   
 => "aaaa"

  DB<130> $_ =~ /${match}{1}+a/   

  DB<131> $_ =~ /(?>${match})a/   

  DB<132>
[download]

It seems to show that perlre is wrong with the redundant anotation.¹

edit

Answering your root question, IMHO using + as a second quantifier like in a++ only makes sense if you already need to use a first quantifier in the first level of interpolation, like in

($pat1)++($pat2)*+

i.e. + and * are not part of a sub-pattern $patN.

Otherwise I'd always prefer

(?>$pat1)(?>$pat2)

using something like ($pat){1}+ seems quite confusing for me.

Cheers Rolf
_{(addicted to the Perl Programming Language and ☆☆☆☆ :)
Je suis Charlie!}

¹) if "redundant" is supposed to mean line 131 and 130 are equivalent, then redundant is a misleading wording

I just ignored that the + is a possessive quantifier in this combination.

But its still redundant like the docs you cited say, backtracking wouldn't change without the plus. ¹

(as far as I understand the docs with my pre coffee brain and without possibility to test on my mobile)

Cheers Rolf
_{(addicted to the Perl Programming Language and ☆☆☆☆ :)
Je suis Charlie!}

¹) no that's not true, see discussion further down!