Fix regeneration of multi-file dependencies

[hcoop/domtool2.git] / src / ast.sml

diff --git a/src/ast.sml b/src/ast.sml
index 3fdc22f..d4c5727 100644 (file)
--- a/src/ast.sml
+++ b/src/ast.sml
@@ -1,5 +1,5 @@
 (* HCoop Domtool (http://hcoop.sourceforge.net/)
- * Copyright (c) 2006, Adam Chlipala
+ * Copyright (c) 2006-2007, Adam Chlipala
  *
  * This program is free software; you can redistribute it and/or
  * modify it under the terms of the GNU General Public License
@@ -14,7 +14,7 @@
  * You should have received a copy of the GNU General Public License
  * along with this program; if not, write to the Free Software
  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
-*)
+ *)
 
 (* Configuration language abstract syntax *)
 
@@ -23,18 +23,18 @@ structure Ast = struct
 open DataStructures
 
 (* A description of a predicate on configuration block stacks *)
-datatype context' =
+datatype pred' =
         CRoot
        (* The stack is empty. *)
        | CConst of string
-       (* The given context name is on top of the stack. *)
-       | CPrefix of context
-       (* Some prefix of the stack matches the context. *)
-       | CNot of context
-       (* The context does not match. *)
-       | CAnd of context * context
-       (* Both contexts match. *)
-withtype context = context' * position
+       (* The given pred name is on top of the stack. *)
+       | CPrefix of pred
+       (* Some prefix of the stack matches the pred. *)
+       | CNot of pred
+       (* The pred does not match. *)
+       | CAnd of pred * pred
+       (* Both preds match. *)
+withtype pred = pred' * position
 
 datatype typ' =
         TBase of string
@@ -43,13 +43,23 @@ datatype typ' =
        (* SML 'a list *)
        | TArrow of typ * typ
        (* SML -> *)
-       | TAction of context * record * record
+       | TAction of pred * record * record
        (* An action that:
-       *  - Is valid in the given context
+       *  - Is valid in the given pred
        *  - Expects an environment compatible with the first record
        *  - Modifies it according to the second record *)
+       | TNested of pred * typ
+       (* Allow nested configuration, in the form of a function from an action
+       * satisfying the first predicate to an action satisfying the second and
+       * with the same environment variable IO behavior. *)
+
+       | TError
+       (* Marker that something already went wrong, so don't generate further
+       * error messages. *)
+       | TUnif of string * typ option ref
+       (* Unification variable to be determined during type-checking *)
 withtype typ = typ' * position
-     and record = typ StringMap.map
+     and record = (typ' * position) StringMap.map
 
 datatype exp' =
         EInt of int
@@ -59,19 +69,55 @@ datatype exp' =
        | EList of exp list
        (* Basic list constructor *)
 
-       | ELam of string * typ * exp
+       | ELam of string * typ option * exp
        (* Function abstraction *)
+       | EVar of string
+       (* Variable bound by a function *)
        | EApp of exp * exp
        (* Function application *)
 
+       | ESkip
+       (* Do-nothing action *)
        | ESet of string * exp
        (* Set an environment variable *)
+       | EGet of string * typ option * string * exp
+       (* Get an environment variable *)
        | ESeq of exp list
        (* Monad sequencer; execute a number of commands in order *)
-       | ELocal of exp
-       (* Local execution; execute the action and then restore the previous
-       * environment. *)
+       | ELocal of exp * exp
+       (* Local execution; like ESeq, but the writes of the first
+       * action are abandoned *)
+       | EWith of exp * exp
+       (* Apply a TNested to an action *)
+       | EALam of string * pred * exp
+       (* Abstraction for building TNested values *)
+       | EIf of exp * exp * exp
+       (* If..then..else *)
 withtype exp = exp' * position
 
+datatype decl' =
+        DExternType of string
+       | DExternVal of string * typ
+       | DVal of string * typ option * exp
+       | DContext of string
+type decl = decl' * string option * position
+
+type file = string option * decl list * exp option
+
+fun multiApp (f, loc, args) =
+    foldl (fn (arg, e) => (EApp (e, arg), loc)) f args
+
+datatype unification_error =
+        UnifyPred of pred * pred
+       | UnifyTyp of typ * typ
+       | UnifyOccurs of string * typ
+
+exception Unify of unification_error
+
+datatype type_error =
+        WrongType of string * exp * typ * typ * unification_error option
+       | WrongForm of string * string * exp * typ * unification_error option
+       | UnboundVariable of string
+       | WrongPred of string * pred * pred
 
 end