add void type

ast.ml

@@ -1,4 +1,5 @@
 type type_t =
+  | Void_t
   | Int_t
   | Bool_t
   | Func_t of type_t * type_t list
@@ -7,6 +8,7 @@ module Syntax = struct
   type ident = string
 
   type value =
+    | Void
     | Int of int
     | Bool of bool
 
@@ -48,6 +50,7 @@ module IR = struct
   type ident = string
 
   type value =
+    | Void
     | Int of int
     | Bool of bool
 

compiler.ml

@@ -11,6 +11,7 @@ type info =
   }
 
 let compile_value = function
+  | Void -> [ Li (V0, 0) ]
   | Int n -> [ Li (V0, n) ]
   | Bool b -> [ Li (V0, if b then 1 else 0) ]
 ;;

errors.ml

@@ -15,6 +15,7 @@ let err msg pos =
 
 let errt expected given pos =
   let rec string_of_type_t = function
+    | Void_t -> "void"
     | Int_t -> "int"
     | Bool_t -> "bool"
     | Func_t (r, a) ->

lexer.mll

@@ -14,10 +14,11 @@ rule token = parse
 | [ ' ' '\t' ]  { token lexbuf }
 | '\n'          { Lexing.new_line lexbuf; token lexbuf }
 | num+ as n     { Lint (int_of_string n) }
+| bool as b     { Lbool (bool_of_string b) }
 | "return"      { Lreturn }
 | "int"         { Ltype (Int_t) }
 | "bool"        { Ltype (Bool_t) }
-| bool as b     { Lbool (bool_of_string b) }
+| "void"        { Ltype (Void_t) }
 | '='           { Lassign }
 | ';'           { Lsc }
 | '+'           { Ladd }

semantics.ml

@@ -4,6 +4,7 @@ open Baselib
 open Errors
 
 let analyze_value = function
+  | Syntax.Void -> Void, Void_t
   | Syntax.Int n -> Int n, Int_t
   | Syntax.Bool b -> Bool b, Bool_t
 ;;
@@ -68,6 +69,7 @@ let analyze parsed = analyze_block _types_ [] parsed
 
 let emit oc ast =
   let rec fmt_v = function
+    | Void -> "Void"
     | Int n -> "Int " ^ string_of_int n
     | Bool b -> "Bool " ^ string_of_bool b
   and fmt_e = function