sub lambda {
    my $f = $_[1];
    for my $x ( $_[0] ) {
        return sub {
            local $x = $_[0];
            return $f->();
        }
    }
}

##</code><code>##

sub Y {
    my ( $curried_rec ) = @_;
    sub {
        my ( $f1 ) = @_;
        $curried_rec->( sub { $f1->( $f1 )->( @_ ) } )
    }->( sub {
        my ( $f2 ) = @_;
        $curried_rec->( sub { $f2->( $f2 )->( @_ ) } )
    } )
}

##</code><code>##

print Y( sub {
    my ( $rec ) = @_;
    sub {
        my ( $n ) = @_;
        $n < 2 ? 1 : $n * $rec->( $n - 1 );
    }
} )->( 10 );;

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