Although you already have a working solution, I took this as a puzzle where the array

Here is my (not so serious) solution: 

#!/usr/bin/perl

use strict;
use warnings;

my @data = <DATA>;

for ((my $i, local $_, my $next) = (0, @data[0, 1]);
        $i < @data;
        ($_, $next) = ($next, $data[++$i + 1])) {
    $next and $next =~ /^\s/ and ($_, $next) = ($_ . $next, $data[++$i
+ + 1]) and redo;

    # processing goes here
    print "#$i: $_";
}

__DATA__
keyword1 data1 data2 data3
keyword2 data1 data2 data3
    data4 data5
    data6
keyword1 data1 data2 data3 data4
keyword3 data1

[download]
which gives: 
#0: keyword1 data1 data2 data3
#3: keyword2 data1 data2 data3
    data4 data5
    data6
#4: keyword1 data1 data2 data3 data4
#5: keyword3 data1

[download]

Greetings,
-jo

$gryYup$d0ylprbpriprrYpkJl2xyl~rzg??P~5lp2hyl0p$

In reply to Re^2: Manually incrementing @ array during for by jo37
in thread Manually incrementing @ array during for by cniggeler

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