From: Simon Marlow Date: Mon, 10 Apr 2006 09:38:24 +0000 (+0000) Subject: add a note about full-laziness X-Git-Url: http://git.megacz.com/?p=ghc-hetmet.git;a=commitdiff_plain;h=57aa4c8a73431b78a37428eb32af5978bfdc5f2b add a note about full-laziness --- diff --git a/docs/users_guide/using.xml b/docs/users_guide/using.xml index 8cbcd35..b274f62 100644 --- a/docs/users_guide/using.xml +++ b/docs/users_guide/using.xml @@ -1383,6 +1383,16 @@ f "2" = 2 Turns off the full laziness optimisation (also known as let-floating). Full laziness increases sharing, which can lead to increased memory residency. + + NOTE: GHC doesn't implement complete full-laziness. + When optimisation in on, and + is not given, some + transformations that increase sharing are performed, such + as extracting repeated computations from a loop. These + are the same transformations that a fully lazy + implementation would do, the difference is that GHC + doesn't consistently apply full-laziness, so don't rely on + it.