public <B> TreePattern<B> map(final Function<? super V, ? extends B> mapper) {
		return new TreePattern<>(_pattern.map(d -> d.map(mapper)));
	}
Maps {@code this} tree-pattern from type {@code V} to type {@code B}.

@param mapper the type mapper
@param <B> the target type
@return a new tree-pattern for the mapped type
jenetics.ext/src/main/java/io/jenetics/ext/rewriting/TreePattern.java