Annotation of /sml/trunk/src/smlnj-lib/Reactive/reactive.sml

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Original Path: sml/branches/SMLNJ/src/smlnj-lib/Reactive/reactive.sml

1 :	monnier	2	(* reactive.sml
2 :			*
3 :			* COPYRIGHT (c) 1997 Bell Labs, Lucent Technologies.
4 :			*
5 :			* A simple ractive engine modelled after RC and SugarCubes.
6 :			*)
7 :
8 :			structure Reactive : REACTIVE =
9 :			struct
10 :
11 :			structure I = Instruction
12 :			structure M = Machine
13 :
14 :			type machine = M.machine
15 :			type instruction = machine Instruction.instr
16 :			type signal = I.signal
17 :			type config = I.signal I.config
18 :			type in_signal = M.in_signal
19 :			type out_signal = M.out_signal
20 :
21 :			(* used to bind internal signal names *)
22 :			structure AMap = AtomBinaryMap
23 :
24 :			exception UnboundSignal of I.signal
25 :
26 :			fun machine {inputs, outputs, body} = let
27 :			val nextId = ref 0
28 :			val sigList = ref []
29 :			fun newSignal s = let
30 :			val id = !nextId
31 :			val s' = M.SIG{name=s, id=id, state = ref 0}
32 :			in
33 :			nextId := id+1;
34 :			sigList := s' :: !sigList;
35 :			s'
36 :			end
37 :			fun bindSig (env, s) = (case AMap.find (env, s)
38 :			of NONE => raise UnboundSignal s
39 :			| (SOME s') => s'
40 :			(* end case *))
41 :			fun trans (instr, env) = (case instr
42 :			of I.||(i1, i2) => M.||(trans(i1, env), trans(i2, env))
43 :			| I.&(i1, i2) => M.&(trans(i1, env), trans(i2, env))
44 :			| I.nothing => M.nothing
45 :			| I.stop => M.stop()
46 :			| I.suspend => M.suspend()
47 :			| I.action act => M.action act
48 :			| I.exec{start, stop, done} =>
49 :			M.exec{start=start, stop=stop, done=done}
50 :			| I.ifThenElse(pred, i1, i2) =>
51 :			M.ifThenElse(pred, trans(i1, env), trans(i2, env))
52 :			| I.repeat(cnt, i) => M.repeat(cnt, trans(i, env))
53 :			| I.loop i => M.loop(trans(i, env))
54 :			| I.close i => M.close(trans(i, env))
55 :			| I.signal(s, i) => trans(i, AMap.insert(env, s, newSignal s))
56 :			| I.rebind(s1, s2, i) =>
57 :			trans(i, AMap.insert(env, s2, bindSig(env, s1)))
58 :			| I.emit s => M.emit(bindSig(env, s))
59 :			| I.await cfg => M.await(transConfig(cfg, env))
60 :			| I.when(cfg, i1, i2) =>
61 :			M.when(transConfig(cfg, env), trans(i1, env), trans(i2, env))
62 :			| I.trapWith(cfg, i1, i2) =>
63 :			M.trapWith(transConfig(cfg, env), trans(i1, env), trans(i2, env))
64 :			(* end case *))
65 :			and transConfig (cfg, env) = let
66 :			fun transCfg (I.posConfig s) = I.posConfig(bindSig(env, s))
67 :			| transCfg (I.negConfig s) = I.negConfig(bindSig(env, s))
68 :			| transCfg (I.orConfig(cfg1, cfg2)) =
69 :			I.orConfig(transCfg cfg1, transCfg cfg2)
70 :			| transCfg (I.andConfig(cfg1, cfg2)) =
71 :			I.andConfig(transCfg cfg1, transCfg cfg2)
72 :			in
73 :			transCfg cfg
74 :			end
75 :			val inputs' = List.map newSignal inputs
76 :			val outputs' = List.map newSignal outputs
77 :			fun ins (s as M.SIG{name, ...}, env) = AMap.insert(env, name, s)
78 :			val initialEnv =
79 :			List.foldl ins (List.foldl ins AMap.empty inputs') outputs'
80 :			val body' = trans (body, initialEnv)
81 :			in
82 :			M.M{
83 :			now = ref 0,
84 :			moveFlg = ref false,
85 :			endOfInstant = ref false,
86 :			prog = body',
87 :			signals = !sigList,
88 :			inputs = inputs',
89 :			outputs = outputs'
90 :			}
91 :			end
92 :
93 :			val run = M.runMachine
94 :			val reset = M.resetMachine
95 :			val inputsOf = M.inputsOf
96 :			val outputsOf = M.outputsOf
97 :			val inputSignal = M.inputSignal
98 :			val outputSignal = M.outputSignal
99 :			val setInSignal = M.setInSignal
100 :			val getInSignal = M.getInSignal
101 :			val getOutSignal = M.getOutSignal
102 :
103 :			val posConfig = I.posConfig
104 :			val negConfig = I.negConfig
105 :			val orConfig = I.orConfig
106 :			val andConfig = I.andConfig
107 :
108 :			val || = I.||
109 :			val & = I.&
110 :			val nothing = I.nothing
111 :			val stop = I.stop
112 :			val suspend = I.suspend
113 :			val action = I.action
114 :			val exec = I.exec
115 :			val ifThenElse = I.ifThenElse
116 :			val repeat = I.repeat
117 :			val loop = I.loop
118 :			val close = I.close
119 :			val signal = I.signal
120 :			val rebind = I.rebind
121 :			val when = I.when
122 :			val trapWith = I.trapWith
123 :			fun trap (c, i) = I.trapWith(c, i, I.nothing)
124 :			val emit = I.emit
125 :			val await = I.await
126 :
127 :			end

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