It's a small gem providing algebraic types and pattern matching on them for Ruby.
- Documentation: http://blog.pitr.ch/algebrick
- Source: https://github.com/pitr-ch/algebrick
- Blog: http://blog.pitr.ch/blog/categories/algebrick/
- Defining data structures.
- Algebraic types play nice with JSON serialization and deserialization. It is ideal for defining message-based cross-process communication.
- and more...
Let's define a Tree
Tree = Algebrick.type do |tree|
variants Empty = atom,
Leaf = type { fields Integer },
Node = type { fields tree, tree }
endNow types Tree(Empty | Leaf | Node), Empty, Leaf(Integer) and Node(Tree, Tree) are defined.
Add some methods, don't miss the pattern matching example.
module Tree
# compute depth of a tree
def depth
match self,
Empty >> 0,
Leaf >> 1,
# ~ will store and pass matched parts to variables left and right
Node.(~any, ~any) >-> left, right do
1 + [left.depth, right.depth].max
end
end
endMethods are defined on all values of type Tree
Empty.depth # => 0
Leaf[10].depth # => 1
Node[Leaf[4], Empty].depth # => 2
Node[Empty, Node[Leaf[1], Empty]].depth # => 3