Proposal : ContT : minimal usage example of shift/reset
Nobody has claimed this yet.
Assessment
- Difficulty
- 2/5
- Estimated time
- 1-3 hours
- Newbie friendliness
- 42/100
- Issue type
- Documentation
- Clarity
- Mostly clear
- Activity status
- Stale
- Tech stack
- haskell
- Domain
- documentation
Research direction
Start with the ContT Haddocks and the shiftT/resetT entry points mentioned in the issue, then determine where a minimal usage example belongs. Add the proposed example or an equivalent demonstration, and confirm that the Haddocks clearly explain the resulting non-local control flow and output.
Written by the indexing model from the issue text.
Description
[original issue 81 by @ocramz]
Since delimited continuations are far from intuitive, I would like to add at least one usage example to their haddocks, something along these lines :
-- | demonstration of non-local control flow with a single shift/reset pair
--
-- λ> flip runState [] $ evalContT t1
-- (2,[2,0,1])
t1 :: ContT Int (State [Int]) Int
t1 = resetT $ do
let
x = 1 -- input
cons w = lift $ modify (w :)
r <- shiftT $ \k -> do
cons x -- initial state uses the input
let y = succ x -- compute a function of the input
z <- lift $ k y -- delegate to the continuation k
cons z -- mutate state with the return value of k
pure y
cons 0
pure r- Dominant language
- Haskell
- Stars
- 5
- Forks
- 10
- PR merge metrics
- No merged PRs in 30d
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First steps
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