Commit | Line | Data |
---|---|---|
a3698041 AC |
1 | (* HCoop Domtool (http://hcoop.sourceforge.net/) |
2 | * Copyright (c) 2006, Adam Chlipala | |
3 | * | |
4 | * This program is free software; you can redistribute it and/or | |
5 | * modify it under the terms of the GNU General Public License | |
6 | * as published by the Free Software Foundation; either version 2 | |
7 | * of the License, or (at your option) any later version. | |
8 | * | |
9 | * This program is distributed in the hope that it will be useful, | |
10 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
11 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
12 | * GNU General Public License for more details. | |
13 | * | |
14 | * You should have received a copy of the GNU General Public License | |
15 | * along with this program; if not, write to the Free Software | |
16 | * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. | |
17 | *) | |
18 | ||
19 | (* Execution of Domtool programs reduced to primitive actions *) | |
20 | ||
21 | structure Eval :> EVAL = struct | |
22 | ||
23 | open Ast | |
24 | ||
25 | structure SM = StringMap | |
26 | ||
27 | fun lookup (evs, ev) = | |
28 | case SM.find (evs, ev) of | |
29 | NONE => raise Fail ("Couldn't find an environment variable " | |
30 | ^ ev ^ " that type-checking has guaranteed") | |
31 | | SOME v => v | |
32 | ||
33 | val conjoin : Env.env_vars * Env.env_vars -> Env.env_vars = | |
34 | SM.unionWith #2 | |
35 | ||
36 | fun findPrimitive e = | |
37 | let | |
38 | fun findPrim (e, _) = | |
39 | case e of | |
40 | EVar name => (name, []) | |
41 | | EApp (e1, e2) => | |
42 | let | |
43 | val (name, args) = findPrim e1 | |
44 | in | |
45 | (name, e2 :: args) | |
46 | end | |
47 | | _ => raise Fail "Non-primitive action left after reduction" | |
48 | ||
49 | val (name, args) = findPrim e | |
50 | in | |
51 | (name, rev args) | |
52 | end | |
53 | ||
54 | fun exec evs e = | |
55 | let | |
56 | fun exec' evs (eAll as (e, _)) = | |
57 | case e of | |
58 | ESkip => SM.empty | |
59 | | ESet (ev, e) => SM.insert (SM.empty, ev, e) | |
60 | | EGet (x, ev, e) => exec' evs (Reduce.subst x (lookup (evs, ev)) e) | |
61 | | ESeq es => | |
62 | let | |
63 | val (new, _) = | |
64 | foldl (fn (e, (new, keep)) => | |
65 | let | |
66 | val new' = exec' keep e | |
67 | in | |
68 | (conjoin (new, new'), | |
69 | conjoin (keep, new')) | |
70 | end) (SM.empty, evs) es | |
71 | in | |
72 | new | |
73 | end | |
74 | | ELocal (e1, e2) => | |
75 | let | |
76 | val evs' = exec' evs e1 | |
77 | val evs'' = exec' (conjoin (evs, evs')) e2 | |
78 | in | |
79 | conjoin (evs, evs'') | |
80 | end | |
81 | | EWith (e1, e2) => | |
82 | let | |
83 | val (prim, args) = findPrimitive e1 | |
84 | in | |
85 | case Env.container prim of | |
86 | NONE => raise Fail "Unbound primitive container" | |
87 | | SOME (action, cleanup) => | |
88 | let | |
89 | val evs' = action (evs, args) | |
90 | val evs'' = exec' evs e2 | |
91 | in | |
92 | cleanup (); | |
93 | conjoin (conjoin (evs, evs'), evs'') | |
94 | end | |
95 | end | |
96 | ||
97 | | _ => | |
98 | let | |
99 | val (prim, args) = findPrimitive eAll | |
100 | in | |
101 | case Env.action prim of | |
102 | NONE => raise Fail "Unbound primitive action" | |
103 | | SOME action => action (evs, args) | |
104 | end | |
105 | ||
106 | val evs' = exec' evs e | |
107 | in | |
108 | () | |
109 | end | |
110 | ||
111 | end |