src/defaults.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 (* Default record field database *)
  20
  21 structure Defaults :> DEFAULTS = struct
  22
  23 open Ast Print
  24
  25 structure SM = StringMap
  26
  27 val dmy = ErrorMsg.dummyLoc
  28
  29 val defaultT : record ref = ref SM.empty
  30 val defaultV : (unit -> exp) SM.map ref = ref SM.empty
  31
  32 fun registerDefault (name, t, v) =
  33     case SM.find (!defaultT, name) of
  34         NONE => (defaultT := SM.insert (!defaultT, name, t);
  35                  defaultV := SM.insert (!defaultV, name, v))
  36       | SOME _ => raise Fail "Duplicate default environment variable"
  37
  38 fun tInit () = (TAction ((CRoot, dmy),
  39                          !defaultT,
  40                          StringMap.empty),
  41                 dmy)
  42
  43 fun eInit () = SM.map (fn f => f ()) (!defaultV)
  44
  45
  46 end