Require a bang pattern when unlifted types are where/let bound; #3182

[ghc-hetmet.git] / compiler / basicTypes / Unique.lhs

diff --git a/compiler/basicTypes/Unique.lhs b/compiler/basicTypes/Unique.lhs
index 36a5352..aecd372 100644 (file)
--- a/compiler/basicTypes/Unique.lhs
+++ b/compiler/basicTypes/Unique.lhs
@@ -17,7 +17,11 @@ Haskell).
 
 \begin{code}
 module Unique (
-       Unique, Uniquable(..), hasKey,
+        -- * Main data types
+       Unique, Uniquable(..), 
+       
+       -- ** Constructors, desctructors and operations on 'Unique's
+       hasKey,
 
        pprUnique, 
 
@@ -32,6 +36,8 @@ module Unique (
 
        isTupleKey, 
 
+        -- ** Making built-in uniques
+
        -- now all the built-in Uniques (and functions to make them)
        -- [the Oh-So-Wonderful Haskell module system wins again...]
        mkAlphaTyVarUnique,
@@ -54,6 +60,7 @@ import BasicTypes
 import FastTypes
 import FastString
 import Outputable
+import StaticFlags
 
 #if defined(__GLASGOW_HASKELL__)
 --just for implementing a fast [0,61) -> Char function
@@ -75,6 +82,10 @@ Fast comparison is everything on @Uniques@:
 
 \begin{code}
 --why not newtype Int?
+
+-- | The type of unique identifiers that are used in many places in GHC
+-- for fast ordering and equality tests. You should generate these with
+-- the functions from the 'UniqSupply' module
 data Unique = MkUnique FastInt
 \end{code}
 
@@ -123,8 +134,8 @@ newTagUnique u c = mkUnique c i where (_,i) = unpkUnique u
 mkUnique c i
   = MkUnique (tag `bitOrFastInt` bits)
   where
-    tag  = fastOrd (cUnbox c) `shiftLFastInt` _ILIT(24)
-    bits = iUnbox i `bitAndFastInt` _ILIT(16777215){-``0x00ffffff''-}
+    !tag  = fastOrd (cUnbox c) `shiftLFastInt` _ILIT(24)
+    !bits = iUnbox i `bitAndFastInt` _ILIT(16777215){-``0x00ffffff''-}
 
 unpkUnique (MkUnique u)
   = let
@@ -145,6 +156,7 @@ unpkUnique (MkUnique u)
 %************************************************************************
 
 \begin{code}
+-- | Class of things that we can obtain a 'Unique' from
 class Uniquable a where
     getUnique :: a -> Unique
 
@@ -199,11 +211,9 @@ We do sometimes make strings with @Uniques@ in them:
 \begin{code}
 pprUnique :: Unique -> SDoc
 pprUnique uniq
-#ifdef DEBUG
   | opt_SuppressUniques
   = empty      -- Used exclusively to suppress uniques so you 
   | otherwise  -- can compare output easily
-#endif
   = case unpkUnique uniq of
       (tag, u) -> finish_ppr tag u (text (iToBase62 u))
 
@@ -256,7 +266,7 @@ iToBase62 n_
 #if defined(__GLASGOW_HASKELL__)
     --then FastInt == Int#
     chooseChar62 n = C# (indexCharOffAddr# chars62 n)
-    chars62 = "0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ"#
+    !chars62 = "0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ"#
 #else
     --Haskell98 arrays are portable
     chooseChar62 n = (!) chars62 n
@@ -277,13 +287,14 @@ Allocation of unique supply characters:
        X:   uniques derived by deriveUnique
        _:   unifiable tyvars   (above)
        0-9: prelude things below
+            (no numbers left any more..)
+       ::   (prelude) parallel array data constructors
 
        other a-z: lower case chars for unique supplies.  Used so far:
 
        d       desugarer
        f       AbsC flattener
        g       SimplStg
-       l       ndpFlatten
        n       Native codegen
        r       Hsc name cache
        s       simplifier
@@ -326,8 +337,8 @@ mkTupleDataConUnique Unboxed a      = mkUnique '8' (2*a)
 isTupleKey u = case unpkUnique u of
                (tag,_) -> tag == '4' || tag == '5' || tag == '7' || tag == '8'
 
-mkPrimOpIdUnique op            = mkUnique '9' op
-mkPreludeMiscIdUnique i                = mkUnique '0' i
+mkPrimOpIdUnique op         = mkUnique '9' op
+mkPreludeMiscIdUnique  i    = mkUnique '0' i
 
 -- No numbers left anymore, so I pick something different for the character
 -- tag