#!/usr/bin/env perl
use strict;
use warnings;

my @tokens = qw/report_time report_day reset read/;
my @abbrev;

for my $token (@tokens) {
    if (1 == grep /^$token/, @tokens) {
        push @abbrev, $token;
    } else {
        die "Error: $token is not unique in list of tokens\n";
    }

    # Generate abbreviations that match only one token
    my $abbrev = $token;
    while (1) {
        chop($abbrev);
        last unless (1 == grep /^$abbrev/, @tokens);
        push @abbrev, $abbrev;
    }
}

# Show the abbreviations
print "Abbreviations = (" . join(',', sort @abbrev) . ")\n";

# Create the regex string to use
my $regex = join('|', sort @abbrev);
print "Token regex = \"$regex\"\n\n";

# Read the file and output tokens

while (<>) {
    my $match;
    if (($match) = m/^($regex)$/) {
        my @matches = grep /^$match/, @tokens;
        print "$match matched for @matches on line $.\n";
    }
}

exit;