* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*)
-val evaluate : Ast.env -> Ast.expr list -> unit
-(** This drives evaluation of the list of expressions (in parallel)
- until they are complete or we reach an error. *)
+(** Take any expression and simplify it down to a constant.
+ If the expression cannot be simplified then this raises
+ [Failure _]. *)
+val to_constant : Ast.env -> Ast.expr -> Ast.constant
+
+(** Take a substitution list and try to turn it into a simple
+ string by evaluating every variable. If not possible this
+ raises [Failure _]. *)
+val substitute : Ast.env -> Ast.loc -> Ast.substs -> string
+
+(** Run a code section. Returns the exit code.
+ Raises [Failure _] on error. *)
+val run_code : Ast.env -> Ast.loc -> Ast.code -> int
+
+(** Run a code section. Returns the exit code and the full stdout
+ as a string. Raises [Failure _] on error. *)
+val run_code_to_string : Ast.env -> Ast.loc -> Ast.code -> int * string
+
+(** Run a code section. Returns the exit code and the full stdout
+ as a list of strings. Raises [Failure _] on error. *)
+val run_code_to_string_list : Ast.env -> Ast.loc -> Ast.code ->
+ int * string list
+
+(** Evaluate a goal argument. This substitutes any variables found,
+ and recursively calls functions. *)
+val evaluate_goal_arg : Ast.env -> Ast.expr -> Ast.expr
+
+(* Call a function. *)
+val call_function : Ast.env -> Ast.loc -> Ast.id -> Ast.expr list -> Ast.func ->
+ Ast.expr