Parsing a FASTA file

fasta.pl

#!/usr/bin/env perl

use 5.010;
use strict;
use warnings;

use Bio::SeqIO;

my $file = shift;
my $in = Bio::SeqIO->new(-format => 'fasta', -file => $file);

my $ct = 0;

while (my $record  = $in->next_seq) {
    $ct++;
}

say "Count: $ct";

fasta.pl6

use v6;
use Bio::SeqIO;

my $file = @*ARGS.shift;
my $in = Bio::SeqIO.new(:format<fasta>, :file($file));

my $ct = 0;

while $in.next-Seq -> $record {
    $ct++;
}

say "Count: $ct";

grammar.pl6

use v6;
use Bio::Grammar::Fasta;

my $file = @*ARGS.shift;
my $data = Bio::Grammar::Fasta.parsefile($file);

my $ct = 0;
for $data<record> -> $record {
    $ct++;
}

say $ct;

Simple benchmark run

[cjfields@Chriss-MacBook-Air bioperl6]$ time perl fasta.pl sequence.fasta
Count: 12097

real   	0m0.434s
user   	0m0.416s
sys    	0m0.014s
[cjfields@Chriss-MacBook-Air bioperl6]$ time perl6 fasta.pl6 sequence.fasta
Count: 12097

real   	0m4.406s
user   	0m4.284s
sys    	0m0.102s
[cjfields@Chriss-MacBook-Air bioperl6]$ time perl6 grammar.pl6 sequence.fasta
12097

real   	0m2.571s
user   	0m2.491s
sys    	0m0.074s