d18a5a94b47a5cd97ca83d34ce2e7fcc17bcfd50
[hcoop/domtool2.git] / src / env.sml
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 (* Domtool type-checking and reduction environments *)
20
21 structure Env :> ENV = struct
22
23 open Ast
24
25 structure SS = StringSet
26 structure SM = StringMap
27
28 val typeRules : (exp -> bool) SM.map ref = ref SM.empty
29 fun registerType (name, rule) = typeRules := SM.insert (!typeRules, name, rule)
30 fun typeRule name = SM.find (!typeRules, name)
31
32 type env = SS.set * (typ * exp option) SM.map
33 val empty : env = (SS.add (SS.singleton "int", "string"),
34 SM.empty)
35
36 fun lookupType (ts, _) name = SS.member (ts, name)
37 fun lookupVal (_, vs) name =
38 case SM.find (vs, name) of
39 NONE => NONE
40 | SOME (t, _) => SOME t
41 fun lookupEquation (_, vs) name =
42 case SM.find (vs, name) of
43 NONE => NONE
44 | SOME (_, eqo) => eqo
45
46 fun bindType (ts, vs) name = (SS.add (ts, name), vs)
47 fun bindVal (ts, vs) (name, t, eqo) = (ts, SM.insert (vs, name, (t, eqo)))
48
49 end