use MooseX::Syntax::Pluggable;

singleton DatabaseConnection
	version(0.001)
{
	has dbh => (is => 'ro', default => sub {...});
	
	method query (Object $q) {
		my $sth = $self->dbh->prepare($q->sql);
		$sth->execute(@{ $q->parameters // [] });
		return $sth;
	}
}

class Query
	version(0.001)
	is anal
{
	has sql        => (is => 'ro', isa => 'Str');
	has parameters => (is => 'ro', isa => 'ArrayRef|Undef');
}

my $query = Query->new(
	sql        => 'SELECT bar FROM foo WHERE id=?',
	parameters => [12],
	);
my $results = DatabaseConnection->instance->query($query);

my $other_query = Query->new(
	sql        => 'SELECT bar FROM foo WHERE id=?',
	praameters => [12],  # croaks because Query is anal and you misspelt the attribute
	);

This module does more or less the same as MooseX::Declare (without re-inventing the wheel - it gets MooseX::Declare to do the heavy lifting!) but also supports plugins to add further sugar to your syntax.

It also exports the TryCatch sugar.