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| author | Malcolm.Wallace@cs.york.ac.uk <unknown> | 2008-04-22 13:05:47 +0000 |
|---|---|---|
| committer | Malcolm.Wallace@cs.york.ac.uk <unknown> | 2008-04-22 13:05:47 +0000 |
| commit | a83c99633384191fb5c3e7514426aa2d5b12ed0f (patch) | |
| tree | ec147aa2749fc6c88cfd6a3555c28e74ebe8b235 /libraries/base/Unsafe | |
| parent | 2d817e6327b9525b328162176dd71d79c91b13a0 (diff) | |
| download | haskell-a83c99633384191fb5c3e7514426aa2d5b12ed0f.tar.gz | |
Improve docs for unsafeCoerce
Make it clear that compilers differ. Point to GHC docs in GHC.Base, and
add a short description of nhc98's representation-safe conversions.
Diffstat (limited to 'libraries/base/Unsafe')
| -rw-r--r-- | libraries/base/Unsafe/Coerce.hs | 12 |
1 files changed, 10 insertions, 2 deletions
diff --git a/libraries/base/Unsafe/Coerce.hs b/libraries/base/Unsafe/Coerce.hs index 00444bd107..e911c6fc57 100644 --- a/libraries/base/Unsafe/Coerce.hs +++ b/libraries/base/Unsafe/Coerce.hs @@ -14,8 +14,16 @@ -- it is your responsibility to ensure that the old and new types have -- identical internal representations, in order to prevent runtime corruption. -- --- 'unsafeCoerce' is just a trivial wrapper for 'unsafeCoerce#'; --- see the latter for important documentation about correct usage. +-- The types for which 'unsafeCoerce' is representation-safe may differ +-- from compiler to compiler (and version to version). +-- +-- * Documentation for correct usage in GHC will be found under +-- 'unsafeCoerce#' in GHC.Base (around which 'unsafeCoerce' is just a +-- trivial wrapper). +-- +-- * In nhc98, the only representation-safe coercions are between Enum +-- types with the same range (e.g. Int, Int32, Char, Word32), +-- or between a newtype and the type that it wraps. module Unsafe.Coerce (unsafeCoerce) where |