use IPC::System::Simple qw/capturex/;
sub apply_scalar_function_of_x {
	my $f = shift;
	my $x = shift;
	if (!defined $f) {return $x}
	my $lisp = "(display ((lambda (x) ($f)) $x))";
	my $result;
	if (not eval { $result = capturex('guile','-c',$lisp); 1 }) {
		print STDERR "Error executing scheme code using guile.\n";
		return;
	}
	return $result;
}