use warnings;
use strict;

my %index;

while ( my $line = <DATA> ) {
    $line = lc $line;
    $line =~ s/^\P{Alnum}+|\P{Alnum}+$//g;
    my @words = split /\P{Alnum}*\s\P{Alnum}*/, $line;
    for ( 0 .. $#words ) {
        my $word = $words[$_];
        $index{$word}{count}++;
        my ( $pre, $post ) = ( '', '' );
        if ( $_ > 0 ) {
            $pre = $words[ $_ - 1 ];
        }
        if ( $_ < $#words ) {
            $post = $words[ $_ + 1 ];
        }
        push @{ $index{$word}{lines} }, [ $., $pre, $post ];
    }
}

for my $word ( sort keys %index ) {
    print "$word - $index{$word}{count} time"
      . ( $index{$word}{count} == 1 ? '' : 's' ) . ":\n";
    printf "    Line %4d - %s $word %s\n", @$_ for ( @{ $index{$word}{lines} } );
    print "\n";
}

__DATA__
Mary had a little lamb,
A little pork, a little jam,
A little fish, some kangaroo,
A pudding and some cookies too,
An ice cream soda topped with fizz,
And boy how sick our Mary is.

Mary had a little lamb,
Her daddy shot it dead.
And now it goes to school with her,
Between two hunks of bread.