Add LICENSE
[hcoop/domtool2.git] / src / env.sml
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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.
dac62e84 17 *)
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18
19(* Domtool type-checking and reduction environments *)
20
21structure Env :> ENV = struct
22
23open Ast
24
25structure SS = StringSet
26structure SM = StringMap
27
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28type typeRule = exp -> bool
29val typeRules : typeRule SM.map ref = ref SM.empty
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30fun registerType (name, rule) = typeRules := SM.insert (!typeRules, name, rule)
31fun typeRule name = SM.find (!typeRules, name)
32
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33type env_vars = exp SM.map
34type action = env_vars * Ast.exp list -> env_vars
35val actions : action SM.map ref = ref SM.empty
36fun registerAction (name, action) = actions := SM.insert (!actions, name, action)
37fun action name = SM.find (!actions, name)
38
39val containers : (action * (unit -> unit)) SM.map ref = ref SM.empty
40fun registerContainer (name, befor, after) =
41 containers := SM.insert (!containers, name, (befor, after))
42fun container name = SM.find (!containers, name)
43
44fun badArgs name = raise Fail ("Invalid arguments to " ^ name)
45
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46type env = SS.set * (typ * exp option) SM.map
47val empty : env = (SS.add (SS.singleton "int", "string"),
48 SM.empty)
49
50fun lookupType (ts, _) name = SS.member (ts, name)
51fun lookupVal (_, vs) name =
52 case SM.find (vs, name) of
53 NONE => NONE
54 | SOME (t, _) => SOME t
55fun lookupEquation (_, vs) name =
56 case SM.find (vs, name) of
57 NONE => NONE
58 | SOME (_, eqo) => eqo
59
60fun bindType (ts, vs) name = (SS.add (ts, name), vs)
61fun bindVal (ts, vs) (name, t, eqo) = (ts, SM.insert (vs, name, (t, eqo)))
62
63end