--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/lab4/optree.mli	Thu Oct 05 08:04:15 2017 +0100
@@ -0,0 +1,84 @@
+(* lab4/keiko.mli *)
+(* Copyright (c) 2017 J. M. Spivey *)
+
+(* |op| -- type of picoPascal operators *)
+type op = Plus | Minus | Times | Div | Mod | Eq 
+  | Uminus | Lt | Gt | Leq | Geq | Neq 
+  | And | Or | Not | Lsl | Lsr | Asr | BitAnd | BitOr | BitNot
+
+val fOp : op -> Print.arg
+
+(* |symbol| -- global symbols *)
+type symbol = string
+
+val nosym : symbol
+
+val gensym : unit -> symbol
+
+(* |codelab| -- type of code labels *)
+type codelab
+
+val nolab : codelab
+
+(* |label| -- generate a code label *)
+val label : unit -> codelab
+
+val fLab : codelab -> Print.arg
+
+(* |inst| -- type of intermediate instructions *)
+type inst =
+    CONST of int                (* Constant (value) *)
+  | GLOBAL of symbol            (* Global address (symbol) *)
+  | LOCAL of int                (* Local address (offset) *)
+  | REGVAR of int               (* Register (index) *)
+  | LOADC                       (* Load char *)
+  | LOADW                       (* Load word *)
+  | STOREC                      (* Store char *)
+  | STOREW                      (* Store word *)
+  | ARG of int                  (* Pass argument (index) *)
+  | SLINK                       (* Pass static link *)
+  | PCALL of int                (* Call procedure (nparams) *)
+  | RESULTW                     (* Procedure result *)
+  | MONOP of op                 (* Perform unary operation (op) *)
+  | BINOP of op                 (* Perform binary operation (op) *)
+  | OFFSET                      (* Add address and offset *)
+  | BOUND                       (* Array bound check *)
+  | NCHECK                      (* Null pointer check *)
+  | LABEL of codelab            (* Set code label *)
+  | JUMP of codelab             (* Unconditional branch (dest) *)
+  | JUMPC of op * codelab       (* Conditional branch (cond, dest) *)
+  | JCASE of codelab list * codelab (* Jump table *)
+
+  (* Extra instructions *)
+  | LINE of int                 (* Line number *)
+  | NOP
+  | SEQ
+  | AFTER                       (* Expression with side effect *)
+  | DEFTMP of int
+  | TEMP of int                 (* Temporary *)
+
+(* |Inst| -- printf format for instructions *)
+val fInst : inst -> Print.arg
+
+(* |do_monop| -- evaluate unary operation *)
+val do_monop : op -> int -> int
+
+(* |do_binop| -- evaluate binary operation *)
+val do_binop : op -> int -> int -> int
+
+(* |negate| -- find opposite for comparison op *)
+val negate : op -> op
+
+(* Operator trees *)
+
+(* |optree| -- type of operator trees *)
+type optree = Node of inst * optree list
+
+(* |canon| -- eliminate SEQ, NOP, AFTER nodes *)
+val canon : optree -> optree list
+
+(* |flatten| -- move args before calls *)
+val flatten : optree list -> optree list
+
+(* |print_optree| -- output operator tree on stdout with line breaking *)
+val print_optree : string -> optree -> unit