1 files changed, 75 insertions, 0 deletions
diff --git a/frontend/ast_util.ml b/frontend/ast_util.ml
new file mode 100644
index 0000000..a7953ad
--- /dev/null
+++ b/frontend/ast_util.ml
@@ -0,0 +1,75 @@
+open Ast
+open Util
+
+(* Some errors *)
+
+let combinatorial_cycle v = error ("Combinatorial cycle with variable: " ^ v)
+let no_variable e = error ("No such variable: " ^ e)
+let type_error e = error ("Type error: " ^ e)
+let not_implemented e = error ("Not implemented: " ^ e)
+let invalid_arity e = error ("Invalid arity (" ^ e ^ ")")
+
+(* Utility : find declaration of a const / a node *)
+
+let find_const_decl p id =
+  match List.find (function
+                   | AST_const_decl (c, _) when c.c_name = id -> true
+                   | _ -> false) 
+                  p with
+  | AST_const_decl d -> d
+  | _ -> assert false
+
+let find_node_decl p id =
+  match List.find (function
+                   | AST_node_decl (c, _) when c.n_name = id -> true
+                   | _ -> false) 
+                  p with
+  | AST_node_decl d -> d
+  | _ -> assert false
+
+let extract_const_decls =
+  List.fold_left
+    (fun l d -> match d with
+      | AST_const_decl d -> d::l
+      | _ -> l)
+    []
+
+
+
+(* Utility : find instances declared in an expression *)
+
+(* extract_instances :
+      prog -> expr ext -> (id * id * eqs * (var_def * expr ext) list) list
+*)
+let rec extract_instances p e = match fst e with
+  | AST_idconst _ | AST_identifier _
+  | AST_int_const _ | AST_real_const _ | AST_bool_const _ -> []
+  | AST_unary (_, e') | AST_pre (e', _) | AST_not e' -> extract_instances p e'
+  | AST_binary(_, e1, e2) | AST_binary_rel (_, e1, e2) | AST_binary_bool (_, e1, e2)
+  | AST_arrow(e1, e2) ->
+    extract_instances p e1 @ extract_instances p e2
+  | AST_if(e1, e2, e3) ->
+    extract_instances p e1 @ extract_instances p e2 @ extract_instances p e3
+  | AST_instance((f, _), args, id) ->
+    let more = List.flatten (List.map (extract_instances p) args) in
+    let (node, _) = find_node_decl p f in
+    let args_x = List.map2 (fun id arg -> id, arg) node.args args in
+    (f, id, node.body, args_x)::more
+
+(* Utility : find pre declarations in an expression *)
+
+(* extract_pre : expr ext -> (id * expr ext) list *)
+let rec extract_pre e = match fst e with
+  | AST_identifier _ | AST_idconst _
+  | AST_int_const _ | AST_real_const _ | AST_bool_const _ -> []
+  | AST_unary (_, e') | AST_not e' -> extract_pre e'
+  | AST_binary(_, e1, e2) | AST_binary_rel (_, e1, e2) | AST_binary_bool (_, e1, e2)
+  | AST_arrow(e1, e2) ->
+    extract_pre e1 @ extract_pre e2
+  | AST_if(e1, e2, e3) ->
+    extract_pre e1 @ extract_pre e2 @ extract_pre e3
+  | AST_instance((f, _), args, id) ->
+    List.flatten (List.map extract_pre args)
+  | AST_pre(e', n) ->
+    (n, e')::(extract_pre e')
+