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| author | Edward Z. Yang <ezyang@cs.stanford.edu> | 2015-05-28 19:04:37 -0700 |
|---|---|---|
| committer | Edward Z. Yang <ezyang@cs.stanford.edu> | 2015-06-03 10:39:14 -0700 |
| commit | 08558a30c17572453e0f8bcbb483a8cb7f00eafa (patch) | |
| tree | c394fa5a629b6d59e0fc59732d42bdfc1484f575 /docs | |
| parent | cd9c5c6678e206ffcda955f66c26c7a4d89519c9 (diff) | |
| download | haskell-08558a30c17572453e0f8bcbb483a8cb7f00eafa.tar.gz | |
Move liftData and use it as a default definition for Lift.
Summary:
This should make it a lot easier to define Lift instances.
See https://mail.haskell.org/pipermail/libraries/2015-May/025728.html
for motivating discussion.
I needed to muck out some code from Quote into Syntax to get
the definition in the right place; but I would argue that code
never really belonged in Quote to begin with.
Signed-off-by: Edward Z. Yang <ezyang@cs.stanford.edu>
Test Plan: validate
Reviewers: austin, ekmett, goldfire
Subscribers: bgamari, thomie
Differential Revision: https://phabricator.haskell.org/D923
Diffstat (limited to 'docs')
| -rw-r--r-- | docs/users_guide/7.12.1-notes.xml | 12 |
1 files changed, 12 insertions, 0 deletions
diff --git a/docs/users_guide/7.12.1-notes.xml b/docs/users_guide/7.12.1-notes.xml index d0eefabbdb..f217b91cdd 100644 --- a/docs/users_guide/7.12.1-notes.xml +++ b/docs/users_guide/7.12.1-notes.xml @@ -403,6 +403,18 @@ Version number XXXXX (was 2.9.0.0) </para> </listitem> + <listitem> + <para> + The <literal>Lift</literal> type class for lifting values + into Template Haskell splices now has a default signature + <literal>lift :: Data a => a -> Q Exp</literal>, which means + that you do not have to provide an explicit implementation + of <literal>lift</literal> for types which have a <literal>Data</literal> + instance. To manually use this default implementation, you + can use the <literal>liftData</literal> function which is + now exported from <literal>Language.Haskell.TH.Syntax</literal>. + </para> + </listitem> </itemizedlist> </sect3> |