token UNDERSCORE

src/lexer.mll

@@ -146,6 +146,8 @@ rule token = parse
       { newline lexbuf; token lexbuf }
   | space+  
       { token lexbuf }
+  | '_'
+      { UNDERSCORE }
   | lident as id  
       { try Hashtbl.find keywords id with Not_found -> LIDENT id }
   | uident as id  

src/parser.mly

@@ -101,7 +101,8 @@
 %token QUOTE RAISE RAISES READS REAL REC REF RETURNS RIGHTB RIGHTBRIGHTB
 %token RIGHTPAR RIGHTSQ 
 %token SEMICOLON SLASH 
-%token THEN THEORY TIMES TRUE TRY TYPE UNIT USES VARIANT VOID WHILE WITH WRITES
+%token THEN THEORY TIMES TRUE TRY TYPE UNDERSCORE
+%token UNIT USES VARIANT VOID WHILE WITH WRITES
 
 /* Precedences */