1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
|
%
% (c) The University of Glasgow 2006
% (c) The GRASP/AQUA Project, Glasgow University, 1992-1998
%
\begin{code}
module UniqSupply (
-- * Main data type
UniqSupply, -- Abstractly
-- ** Operations on supplies
uniqFromSupply, uniqsFromSupply, -- basic ops
mkSplitUniqSupply,
splitUniqSupply, listSplitUniqSupply,
-- * Unique supply monad and its abstraction
UniqSM, MonadUnique(..),
-- ** Operations on the monad
initUs, initUs_,
lazyThenUs, lazyMapUs,
-- ** Deprecated operations on 'UniqSM'
getUniqueUs, getUs, returnUs, thenUs, mapUs
) where
import Unique
import FastTypes
import MonadUtils
import Control.Monad
import Control.Monad.Fix
import GHC.IOBase (unsafeDupableInterleaveIO)
\end{code}
%************************************************************************
%* *
\subsection{Splittable Unique supply: @UniqSupply@}
%* *
%************************************************************************
\begin{code}
-- | A value of type 'UniqSupply' is unique, and it can
-- supply /one/ distinct 'Unique'. Also, from the supply, one can
-- also manufacture an arbitrary number of further 'UniqueSupply' values,
-- which will be distinct from the first and from all others.
data UniqSupply
= MkSplitUniqSupply FastInt -- make the Unique with this
UniqSupply UniqSupply
-- when split => these two supplies
\end{code}
\begin{code}
mkSplitUniqSupply :: Char -> IO UniqSupply
-- ^ Create a unique supply out of thin air. The character given must
-- be distinct from those of all calls to this function in the compiler
-- for the values generated to be truly unique.
splitUniqSupply :: UniqSupply -> (UniqSupply, UniqSupply)
-- ^ Build two 'UniqSupply' from a single one, each of which
-- can supply its own 'Unique'.
listSplitUniqSupply :: UniqSupply -> [UniqSupply]
-- ^ Create an infinite list of 'UniqSupply' from a single one
uniqFromSupply :: UniqSupply -> Unique
-- ^ Obtain the 'Unique' from this particular 'UniqSupply'
uniqsFromSupply :: UniqSupply -> [Unique] -- Infinite
-- ^ Obtain an infinite list of 'Unique' that can be generated by constant splitting of the supply
\end{code}
\begin{code}
mkSplitUniqSupply c
= case fastOrd (cUnbox c) `shiftLFastInt` _ILIT(24) of
mask -> let
-- here comes THE MAGIC:
-- This is one of the most hammered bits in the whole compiler
mk_supply
= unsafeDupableInterleaveIO (
genSymZh >>= \ u_ -> case iUnbox u_ of { u -> (
mk_supply >>= \ s1 ->
mk_supply >>= \ s2 ->
return (MkSplitUniqSupply (mask `bitOrFastInt` u) s1 s2)
)})
in
mk_supply
foreign import ccall unsafe "genSymZh" genSymZh :: IO Int
splitUniqSupply (MkSplitUniqSupply _ s1 s2) = (s1, s2)
listSplitUniqSupply (MkSplitUniqSupply _ s1 s2) = s1 : listSplitUniqSupply s2
\end{code}
\begin{code}
uniqFromSupply (MkSplitUniqSupply n _ _) = mkUniqueGrimily (iBox n)
uniqsFromSupply (MkSplitUniqSupply n _ s2) = mkUniqueGrimily (iBox n) : uniqsFromSupply s2
\end{code}
%************************************************************************
%* *
\subsubsection[UniqSupply-monad]{@UniqSupply@ monad: @UniqSM@}
%* *
%************************************************************************
\begin{code}
-- | A monad which just gives the ability to obtain 'Unique's
newtype UniqSM result = USM { unUSM :: UniqSupply -> (result, UniqSupply) }
instance Monad UniqSM where
return = returnUs
(>>=) = thenUs
(>>) = thenUs_
instance Functor UniqSM where
fmap f (USM x) = USM (\us -> case x us of
(r, us') -> (f r, us'))
instance Applicative UniqSM where
pure = returnUs
(USM f) <*> (USM x) = USM $ \us -> case f us of
(ff, us') -> case x us' of
(xx, us'') -> (ff xx, us'')
-- | Run the 'UniqSM' action, returning the final 'UniqSupply'
initUs :: UniqSupply -> UniqSM a -> (a, UniqSupply)
initUs init_us m = case unUSM m init_us of { (r,us) -> (r,us) }
-- | Run the 'UniqSM' action, discarding the final 'UniqSupply'
initUs_ :: UniqSupply -> UniqSM a -> a
initUs_ init_us m = case unUSM m init_us of { (r, _) -> r }
{-# INLINE thenUs #-}
{-# INLINE lazyThenUs #-}
{-# INLINE returnUs #-}
{-# INLINE splitUniqSupply #-}
\end{code}
@thenUs@ is where we split the @UniqSupply@.
\begin{code}
instance MonadFix UniqSM where
mfix m = USM (\us -> let (r,us') = unUSM (m r) us in (r,us'))
thenUs :: UniqSM a -> (a -> UniqSM b) -> UniqSM b
thenUs (USM expr) cont
= USM (\us -> case (expr us) of
(result, us') -> unUSM (cont result) us')
lazyThenUs :: UniqSM a -> (a -> UniqSM b) -> UniqSM b
lazyThenUs (USM expr) cont
= USM (\us -> let (result, us') = expr us in unUSM (cont result) us')
thenUs_ :: UniqSM a -> UniqSM b -> UniqSM b
thenUs_ (USM expr) (USM cont)
= USM (\us -> case (expr us) of { (_, us') -> cont us' })
returnUs :: a -> UniqSM a
returnUs result = USM (\us -> (result, us))
getUs :: UniqSM UniqSupply
getUs = USM (\us -> splitUniqSupply us)
-- | A monad for generating unique identifiers
class Monad m => MonadUnique m where
-- | Get a new UniqueSupply
getUniqueSupplyM :: m UniqSupply
-- | Get a new unique identifier
getUniqueM :: m Unique
-- | Get an infinite list of new unique identifiers
getUniquesM :: m [Unique]
getUniqueM = liftM uniqFromSupply getUniqueSupplyM
getUniquesM = liftM uniqsFromSupply getUniqueSupplyM
instance MonadUnique UniqSM where
getUniqueSupplyM = USM (\us -> splitUniqSupply us)
getUniqueM = getUniqueUs
getUniquesM = getUniquesUs
getUniqueUs :: UniqSM Unique
getUniqueUs = USM (\us -> case splitUniqSupply us of
(us1,us2) -> (uniqFromSupply us1, us2))
getUniquesUs :: UniqSM [Unique]
getUniquesUs = USM (\us -> case splitUniqSupply us of
(us1,us2) -> (uniqsFromSupply us1, us2))
mapUs :: (a -> UniqSM b) -> [a] -> UniqSM [b]
mapUs _ [] = returnUs []
mapUs f (x:xs)
= f x `thenUs` \ r ->
mapUs f xs `thenUs` \ rs ->
returnUs (r:rs)
\end{code}
\begin{code}
-- {-# SPECIALIZE mapM :: (a -> UniqSM b) -> [a] -> UniqSM [b] #-}
-- {-# SPECIALIZE mapAndUnzipM :: (a -> UniqSM (b,c)) -> [a] -> UniqSM ([b],[c]) #-}
-- {-# SPECIALIZE mapAndUnzip3M :: (a -> UniqSM (b,c,d)) -> [a] -> UniqSM ([b],[c],[d]) #-}
lazyMapUs :: (a -> UniqSM b) -> [a] -> UniqSM [b]
lazyMapUs _ [] = returnUs []
lazyMapUs f (x:xs)
= f x `lazyThenUs` \ r ->
lazyMapUs f xs `lazyThenUs` \ rs ->
returnUs (r:rs)
\end{code}
|
