Annotation of /trunk/src/common/stamp.sml

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Revision 63 - (view) (download)

1 :	jhr	9	(* stamp.sml
2 :			*
3 :			* COPYRIGHT (c) 2010 The Diderot Project (http://diderot.cs.uchicago.edu)
4 :			* All rights reserved.
5 :			*
6 :			* Stamps are locally unique identifiers used in the compiler to
7 :			* distinguish different types, variables, etc. For a given compilation,
8 :			* the stamp assigned to an object is guaranteed to be unique, although
9 :			* an object may have different stamps assigned to it in different compiles.
10 :			*)
11 :
12 :			structure Stamp :> sig
13 :
14 :			type stamp
15 :
16 :			val new : unit -> stamp
17 :
18 :			val same : (stamp * stamp) -> bool
19 :			val compare : (stamp * stamp) -> order
20 :			val hash : stamp -> word
21 :
22 :			val toString : stamp -> string
23 :
24 :			structure Set : ORD_SET where type Key.ord_key = stamp
25 :			structure Map : ORD_MAP where type Key.ord_key = stamp
26 :			structure Tbl : MONO_HASH_TABLE where type Key.hash_key = stamp
27 :
28 :			end = struct
29 :
30 :			structure W = Word
31 :
32 :			datatype stamp = STAMP of {
33 :			id : Word.word
34 :			}
35 :
36 :			val cnt = ref 0w0
37 :
38 :			fun new () = let val w = !cnt in cnt := w+0w1; STAMP{id = w} end
39 :
40 :			fun same (STAMP{id, ...}, STAMP{id=id', ...}) = (id = id')
41 :			fun compare (STAMP{id, ...}, STAMP{id=id', ...}) = W.compare(id, id')
42 :			fun hash (STAMP{id, ...}) = id
43 :
44 :	jhr	63	fun toString (STAMP{id, ...}) = StringCvt.padLeft #"0" 4 (W.toString id)
45 :	jhr	9
46 :			structure Key =
47 :			struct
48 :			type ord_key = stamp
49 :			val compare = compare
50 :			end
51 :			structure Map = RedBlackMapFn (Key)
52 :			structure Set = RedBlackSetFn (Key)
53 :
54 :			structure Tbl = HashTableFn (struct
55 :			type hash_key = stamp
56 :			fun hashVal (STAMP{id}) = id
57 :			fun sameKey (STAMP{id=a}, STAMP{id=b}) = (a = b)
58 :			end)
59 :
60 :			end
61 :

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