lspitzner / lspitzner/pqueue

Get rid of eqExtract and cmpExtract?

Open
#62 0 comments 0 reactions 0 assignees View on GitHub

Nobody has claimed this yet.

Dominant language
Haskell
Stars
17
Forks
12
PR merge metrics
No merged PRs in 30d

Description

If we enable flexible instances, we can define

```haskell
instance Ord a => Eq (BinomHeap a) where
(==) = (==) `on` extractHeap
instance Ord a => Ord (BinomHeap a) where
compare = compare `on` extractHeap
```

Then

```haskell
deriving instance Ord a => Eq (MinQueue a)

instance Ord a => Ord (MinQueue a) where
Empty `compare` Empty = EQ
Empty `compare` _ = LT
_ `compare` Empty = GT
MinQueue _n1 x1 q1 `compare` MinQueue _n2 x2 q2 = compare (x1,q1) (x2,q2)
```

I haven't compared the Core this generates to what we do now, but I expect it would be similar. The advantage is that this strikes me as significantly easier to read at a glance.

Contributor guide

No contributing guide indexed for this repository

First steps

  1. Read the whole issue, then the project's contributing guide.
  2. Comment on the issue to say you are picking it up — it saves two people doing the same work.
  3. Fork the repository and make your change on a branch.
  4. Open a pull request that references the issue number.

Research direction

Locate eqExtract and cmpExtract and the existing Eq and Ord implementations for BinomHeap and MinQueue. Enable the proposed flexible instances, compare the generated Core with the current implementation, and verify that equality and ordering behavior remain unchanged.

Written by the indexing model from the issue text.

Assessment

Tech stack
haskell
Domain
data
Issue type
Refactor
Difficulty
4/5
Estimated time
3-5 days
Activity status
Stale
Clarity
Mostly clear
Newbie friendliness
35/100

Get new issues in your inbox

A short digest of beginner-friendly GitHub issues.