sumtype 0.1.0

sumtype

A sum type for modern D.

Features

• Pattern matching.
• Self-referential types (This).
• Full attribute-correctness—pure, @safe, and @nogc where applicable.
• No runtime dependency on TypeInfo.

Example

import std.typecons: Tuple, tuple;

alias Tree = SumType!(int, Tuple!(This*, "left", This*, "right"));
alias Node = Tuple!(Tree*, "left", Tree*, "right");

Node node(Tree* left, Tree* right)
{
    return tuple!("left", "right")(left, right);
}

int[] inorder(Tree t)
{
    return t.match!(
        (int leaf) => [leaf],
        (Node node) => inorder(*node.left) ~ inorder(*node.right)
    );
}

Tree x =
    Tree(node(
        new Tree(1),
        new Tree(node(
            new Tree(2),
            new Tree(3)
        ))
    ));

assert(inorder(x) == [1, 2, 3]);

Installation

If you're using dub, add the sumtype package to your project as a dependency.

Alternatively, since it's a single, self-contained module, you can simply copy sumtype.d to your source directory and compile as usual.