htree: a library to build and work with heterogeneous, type level indexed rose trees

[ agpl, data, library ] [ Propose Tags ]

This library implements a heterogeneous rose-tree (HTree) that is indexed by a type-level rosetree (TyTree).

It also offers some useful functions, highlights include:

searching in the tree and creating evidence on the term-level via typeclasses record-dot syntax for accessing elements in the tree. mapping and traversing trees


[Skip to Readme]

Downloads

Maintainer's Corner

Package maintainers

For package maintainers and hackage trustees

Candidates

  • No Candidates
Versions [RSS] 0.1.1.0
Change log CHANGELOG.md
Dependencies base (>=4.16 && <5) [details]
License AGPL-3.0-or-later
Author mangoiv
Maintainer contact@mangoiv.com
Category Data
Uploaded by mangoiv at 2024-07-21T16:45:04Z
Distributions NixOS:0.1.1.0
Downloads 26 total (7 in the last 30 days)
Rating (no votes yet) [estimated by Bayesian average]
Your Rating
  • λ
  • λ
  • λ
Status Docs uploaded by user
Build status unknown [no reports yet]

Readme for htree-0.1.1.0

[back to package description]

built with nix built on haskell ci haddock

htree: heterogeneous rose tree

This library implements a heterogeneous rose-tree (HTree) that is indexed by a type-level rosetree (TyTree).

It also offers some useful functions, highlights include:

  • searching in the tree and creating evidence on the term-level via typeclasses
  • record-dot syntax for accessing elements in the tree.
  • mapping and traversing trees

to develop

  • with direnv: direnv allow
  • only with nix: nix develop
  • to run all checks: nix flake check -Lv systems configurations
  • build with nix nix build (or on ghc96, nix build .#ghc96-htree)
  • documentation in the form of continuously deployed haddock can be found at mangoiv.srht.site

example

pattern I :: forall a. a -> Identity a
pattern I a = Identity a

-- the type that the tree is going to be indexed by
type Ex =
  TyNode Int
   [ TyNode Int
       [ TyNode Int '[]
       , TyNode Bool '[]
       , TyNode String '[ TyNode Int '[]]
       ]
    , TyNode Int '[]
    ]

-- we create an HTree of the example type 'Ex'
ex :: HTree Identity Ex
ex =
  HNode 5 do
    HNode 12 do
      HNode 13 HNil
        ::: HNode (I False) HNil
        ::: HNode "test" (HNode 9 HNil ::: HNil)
        ::: HNil
      ::: HNode 43 HNil
      ::: HNil
    

-- we can create a labeled Tree and search via DFS and BFS in it
-- the search happens on the type-level
type LabeledTree = TyNodeL "top" Int
  [ TyNodeL "inter" Int '[ TyNodeL "foo" Int '[] ]
  , TyNodeL "foo" Int '[]
  ]

-- >>> getElem @'DFS @"foo" @Int Proxy labeledTree
-- Identity 69
-- >>> getElem @'BFS @"foo" @Int Proxy labeledTree
-- Identity 67
labeledTree :: HTree Identity LabeledTree
labeledTree = 42 `HNodeL` HNodeL 4 (HNodeL 69 HNil ::: HNil) ::: HNodeL 67 HNil ::: HNil