Changelog

Version 2.3.3

Date: 2019-10-02

• Fix typo in cats/monad/state.clj: -repr should return a string, not a regex

Version 2.3.2

Date: 2018-11-07

• Introduce haskell-inspired do-let macro

Version 2.3.1

Date: 2018-10-31

• Override put,get,swap to receive monad context

Version 2.3.0

Date: 2018-08-29

• Add state monad implementation

Date: 2018-10-05

• Implement Semigroup for Either

Version 2.2.0

Date: 2018-01-11

• Fix some issues with wrong handling of dynamic context.
• Convert some functions to macros for delay args evaluation.

Version 2.1.0

Date: 2017-04-20

• Make cats work together with core.match for some types.
• Convert when and unless to macros.
• Update promesa dependency.

Version 2.0.0

Date: 2016-07-28

This version intend to clean the library from unused and out of context stuff and leave only the useful abstractions. This is a list of main changes (mostly breaking):

• Removed support for monad transformers. They add too many complex to the implementation but in return adds very low value in context of dynamic languages as is clojure.
• Removed state, writer, reader and continuation monad namespaces. They are not very useful in clojure so having them without any particular usefulness it not make sense.
• Removed cats.applicative namespace because it is too many opinionated and not really useful in the real world. The use case vary depending on when that abstraction is used so we encourage users to define their own abstraction with specific behavior for their application.
• Removed CRDT's labs. It was an experiment and the final sensacion is that is not very useful and in most circumstances the users defines their own datastructures instead of rely on ones from third party packages. So, maintaining them in the code base also does not make sense
• Removed lens and traversals namespaces. The first one becomes very useful and is properly externalized as separated package. The last one, seems like it is not very useful and seems out of context of cats library. If anyone is interested in maintaining it, the code can be extracted from the previos git revisions and released as separated library.
• Move cats.labs.sugar into cats.core namespace (cats.labs.sugar ns is removed)

And a list of other changes and contributions:

• PersistentListq support in sequence context (@muhuk)
• Rewrite cats.labs.channel integration with core.async combinators (@yanatan16)
• Add cats.builtin.lazy-sequence-context (@muhuk)
• Fix bug in sequence context's fapply implementation (@muhuk)
• Performance improvements in sequence context implementation (@muhuk)
• Add cats.monad.either/try-either macro for capturing exceptions as left, values as right (@shmish111)
• Move promesa.monad namespace under cats.labs.promise ns.

Version 1.2.1

Date: 2015-12-16

• Fix functor implementation for Map.
• Fix key overwritting on lenses focus/foci types.
• Add utility functions to validation ns.

Version 1.2.0

Date: 2015-12-01

• Add Bifunctor (@yurrriq)
• Add a macro for lifting functions to applicatives

Version 1.1.0

Date: 2015-11-26

• Add Lenses and Traversals.
• Add timeout support for manifold deferred context.
• Improved mapseq implementation.
• Added function monoid and monad.
• Implement functor, monad and foldable for any kind of map.
• Make all types printable.
• Add monadzero and monadplus for either and either-t.
• Add cats.labs.sugar namespace with sugar syntax macros (documentation is very welcome).
• Update core.async version to 0.2.374
• Update cljs compiler version to 0.7.170
• Add basic support for crdt's under labs namespace. (documentation is missing).
• Add test.check generators integration and property constructors

Version 1.0.0

Date: 2015-09-17

Bug fixes

• The context doesn't need to be a monad anymore.
• Fix Foldable implementation for clojure builtin collections.

New features

• Add additional arity to cats.core/mempty function, that allows provide a context instead of resolving it.
• Sorted map is now also implements monoid.
• Add cats.labs namespace for make room for previously removed reader, writer, state and continuation monads.
• Add core.async channel monad/applicative under cats.labs.channel namespace.
• Add manifold deferred monad/applicative under cats.labs.manifold namespace.
• Add applicative-do (with alet macro) syntax. You can read more about that in haskell wiki and pull request.
• Add foldm implementation to cats.core namespace.
• Add a bunch of monoids: all, any, sum, prod, pair and string.
• Add a Traversable protocol and implementations for vector, sequence, pair, maybe, either and validation.
• Add traverse function to cats.core namespace.

Backwards incompatible changes

• Revisit monad-transformers abstraction removing useless protocol methods: base and inner are no longer part of the MonadTrans protocol.
• The protocols methods are all renamed to -name for consistency with cljs style to name internal functions.
• The Context protocol has been renamed to Contextual, and Context is now a protocol used to mark context instances and resolve their priority.

Version 0.6.1

Date: 2015-08-02

• Remove src/user.clj that causes some problems.

Version 0.6.0

Date: 2015-08-02

• Foldable abstraction.
• Curry facilities.
• Major code cleaning.
• Context management moved into its own namespace.
• A lot of performance improvements (removing unnecessary function call forwarding).
• Start using the clojurescript 1.7.28.

Version 0.5.0

Date: 2015-07-13

• Set default and required clojure version to 1.7.0.
• Replace cljx with clojure 1.7 conditional reader.
• Add more util functions for treat for maybe monad types.
• Add more util functions for treat for either monad types.
• Add semigroup and monoid abstractions.
• Add validation applicative (similar to either).
• Minor performance improvements.
• Fix inconsistences between fmap / fapply public functions and its haskell-style aliases.
• Add more documentation.
• Deprecate the state, reader, writer and continuation monads. They will be moved to a separated library for future version.
• Remove already deprecated from-either function.

Version 0.4.0

Date: 2015-03-25

• The exception monad now raises a exception when you deref a failure instance. This will allow easy use of monadic api from libraries or applications that does not use monads.
• The cats.monad.exception/failure function now coerce all input that not extends from exception to exception type (using ex-info clojure function).
• Add channel monad using core.async channels abstraction (as separated repository) This make easy treat channels as monads and using them in monadic compositions.
• Remove mlet-with macro (bacause it sintax is ugly and with-monad usage is preferable)
• Remove undocumented errlet macro.

Version 0.3.4

Date: 2015-03-14

• Improve cljx build process.

Version 0.3.3

Date: 2015-03-14

• Improvements on project.clj.

Version 0.3.2

Date: 2015-02-08

• Empty version, only exists because clojars does not allow remove wrong uploaded versions.

Version 0.3.0

Date: 2015-02-08

• Dependencies versions update.
• Add new arity to from-maybe function for default value.
• Update required clojurescript version to 0.0-2760.
• Use speclj for tests.
• Add IDeref implementation to either, maybe, identity and exception monads types.
• Remove maybe useless lazy monad.

Version 0.2.0

Date: 2014-10-26

• Major api redesign.
• Split monad definition from data type.
• mlet macro is now not recursive.
• New monads: lazy, exception.
• Monad transformers.

Version 0.1.0

Date: 2014-07-09

• First relase.