streamly/Changelog.md

Unreleased

Breaking changes

• Change the semantics of the Semigroup instance for InterleavedT, AsyncT and ParallelT. The new semantics are as follows:

  • For InterleavedT, <> operation interleaves two streams
  • For AsyncT, <> now concurrently merges two streams in a left biased manner using demand based concurrency.
  • For ParallelT, the <> operation now concurrently meges the two streams in a fairly parallel manner.

  To adapt to the new changes, replace <> with append wherever it is used for streams other than StreamT.

• Change the semantics of Alternative instance. The <|> operator now has a different behavior for each type. See the documentation for more details. To adapt to this change replace any usage of <|> with parallel and empty with nil.

• Stream type now defaults to the SerialT type unless explicitly specified using a type combinator or a monomorphic type. This change reduces puzzling type errors for beginners. It includes the following two changes:

  • Change the type of all stream elimination functions to SerialT. This makes sure that the stream type is always fixed at all exits.
  • Change the type combinators to only fix the argument stream type and the resulting stream type remains polymorphic.

  Stream types may have to be changed or type combinators may have to added or removed to adapt to this change.

• Change the type of foldrM to make it consistent with foldrM in base.

Deprecations

• Deprecate and rename the following symbols:
  • StreamT to SerialT
  • runStreamT to runSerialT
  • ZipStream to ZipSerial
  • runZipStream to runZipSerial
  • AsyncT to AParallelT
  • runAsyncT to runAParallelT
  • asyncly to aparallely
  • Streaming to IsStream
  • runStreaming to runStream
  • <=> to interleave
  • <| to aparallel
  • each to fromFoldable
  • scan to scanx
  • foldl to foldx
  • foldlM to foldxM

Enhancements

• Add the following functions:
  • scanl' strict left scan
  • foldl' strict left fold
  • foldlM' strict left fold with a monadic fold function
  • append run two streams serially one after the other
  • parallel run two streams in parallel (replaces <|>)

0.1.2

Enhancements

• Add iterate, iterateM stream operations

Bug Fixes

• Fixed a bug that casued unexpected behavior when pure was used to inject values in Applicative composition of ZipStream and ZipAsync types.

0.1.1

Enhancements

• Make cons right associative and provide an operator form .: for it
• Add null, tail, reverse, replicateM, scan stream operations
• Improve performance of some stream operations (foldl, dropWhile)

Bug Fixes

• Fix the product operation. Earlier, it always returned 0 due to a bug
• Fix the last operation, which returned Nothing for singleton streams

0.1.0

• Initial release