diff options
| author | Jakob Bruenker <jakob.bruenker@gmail.com> | 2022-03-21 00:14:25 +0100 |
|---|---|---|
| committer | Jakob Bruenker <jakob.bruenker@gmail.com> | 2022-03-31 17:45:37 +0200 |
| commit | a9c0c69b42657d39f26ab822241900ba0f308dc3 (patch) | |
| tree | fd59a5e49146ee436e04137b313d8e4178c2bed0 /docs/users_guide/9.4.1-notes.rst | |
| parent | dda46e2da13268c239db3290720b014cef00c01d (diff) | |
| download | haskell-wip/T20768.tar.gz | |
Implement \cases (Proposal 302)wip/T20768
This commit implements proposal 302: \cases - Multi-way lambda
expressions.
This adds a new expression heralded by \cases, which works exactly like
\case, but can match multiple apats instead of a single pat.
Updates submodule haddock to support the ITlcases token.
Closes #20768
Diffstat (limited to 'docs/users_guide/9.4.1-notes.rst')
| -rw-r--r-- | docs/users_guide/9.4.1-notes.rst | 6 |
1 files changed, 6 insertions, 0 deletions
diff --git a/docs/users_guide/9.4.1-notes.rst b/docs/users_guide/9.4.1-notes.rst index 39ab943356..0bb8b21eee 100644 --- a/docs/users_guide/9.4.1-notes.rst +++ b/docs/users_guide/9.4.1-notes.rst @@ -41,6 +41,12 @@ Language re-exported from ``Prelude``. When ``(~)`` is not in scope, its use results in a warning (:ghc-flag:`-Wtype-equality-out-of-scope`). +- GHC Proposal `#302 <https://github.com/ghc-proposals/ghc-proposals/blob/master/proposals/0302-cases.rst>`_ has been implemented. + This means under ``-XLambdaCase``, a new expression heralded by ``\cases`` is + available, which works like ``\case`` but can match on multiple patterns. + This means constructor patterns with arguments have to parenthesized here, + just like in lambda expressions. + - There were previously cases around functional dependencies and injective type families where the result of type inference would depend on the order of constraints, as written in a source file. These cases are fundamentally ambiguous. |