diff options
| author | Ian Lynagh <ian@well-typed.com> | 2013-02-25 19:02:57 +0000 |
|---|---|---|
| committer | Ian Lynagh <ian@well-typed.com> | 2013-02-25 21:42:42 +0000 |
| commit | 20b98f350d7b30118ca311117903fc039f6b85ce (patch) | |
| tree | 2262ab4eb1ada0d32953ed4a24e49bfbdbe95122 /docs/users_guide | |
| parent | 890f4657e0edc9fa945c1e70ddf1bec1f52b7590 (diff) | |
| download | haskell-20b98f350d7b30118ca311117903fc039f6b85ce.tar.gz | |
Change how unboxed tuples are lexed; fixes #7627
(# is now always a lexeme, even if followed by a symbol.
Diffstat (limited to 'docs/users_guide')
| -rw-r--r-- | docs/users_guide/glasgow_exts.xml | 8 |
1 files changed, 8 insertions, 0 deletions
diff --git a/docs/users_guide/glasgow_exts.xml b/docs/users_guide/glasgow_exts.xml index c4dd6bbf5e..1357395eff 100644 --- a/docs/users_guide/glasgow_exts.xml +++ b/docs/users_guide/glasgow_exts.xml @@ -225,6 +225,14 @@ the same. </para> <para> +Note that when unboxed tuples are enabled, +<literal>(#</literal> is a single lexeme, so for example when using +operators like <literal>#</literal> and <literal>#-</literal> you need +to write <literal>( # )</literal> and <literal>( #- )</literal> rather than +<literal>(#)</literal> and <literal>(#-)</literal>. +</para> + +<para> Unboxed tuples are used for functions that need to return multiple values, but they avoid the heap allocation normally associated with using fully-fledged tuples. When an unboxed tuple is returned, the |