diff --git a/src/bin/owi.ml b/src/bin/owi.ml
index 68e357a2d..acdf51db4 100644
--- a/src/bin/owi.ml
+++ b/src/bin/owi.ml
@@ -376,6 +376,9 @@ let exit_code =
       | `Contract_unknown_func _id -> 71
       | `Empty_annotation_id -> 72
       | `Empty_identifier -> 73
+      | `Unclosed_annotation -> 74
+      | `Unclosed_comment -> 75
+      | `Unclosed_string -> 76
     end
   end
   | Error e -> (
diff --git a/src/parser/parse.ml b/src/parser/parse.ml
index 860c29860..ffcf92da6 100644
--- a/src/parser/parse.ml
+++ b/src/parser/parse.ml
@@ -340,6 +340,9 @@ struct
       | Text_lexer.Empty_identifier -> Error `Empty_identifier
       | Text_lexer.Illegal_escape msg -> Error (`Illegal_escape msg)
       | Text_lexer.Illegal_character msg -> Error (`Lexer_illegal_character msg)
+      | Text_lexer.Unclosed_annotation -> Error `Unclosed_annotation
+      | Text_lexer.Unclosed_comment -> Error `Unclosed_comment
+      | Text_lexer.Unclosed_string -> Error `Unclosed_string
       | Text_lexer.Unknown_operator msg -> Error (`Lexer_unknown_operator msg)
       | Text_parser.Error ->
         let tok = Text_lexer.token buf |> token_to_string in
diff --git a/src/parser/text_lexer.ml b/src/parser/text_lexer.ml
index 5c7ec4caa..8d5d280f5 100644
--- a/src/parser/text_lexer.ml
+++ b/src/parser/text_lexer.ml
@@ -13,6 +13,12 @@ exception Illegal_character of string
 
 exception Illegal_escape of string
 
+exception Unclosed_annotation
+
+exception Unclosed_comment
+
+exception Unclosed_string
+
 exception Unknown_operator of string
 
 let illegal_character buf =
@@ -111,10 +117,12 @@ let id_char =
     | '!' | '#' | '$' | '%' | '&' | '\'' | '*' | '+' | '-' | '.' | '/' | ':'
     | '<' | '=' | '>' | '?' | '@' | '\\' | '^' | '_' | '`' | '|' | '~' )]
 
-let name = [%sedlex.regexp? "\"", Star (Sub (any, "\"") | "\\\""), "\""]
+let string_elem = [%sedlex.regexp? Sub (any, "\"") | "\\\""]
+
+let name = [%sedlex.regexp? "\"", Star string_elem, "\""]
 
 let operator =
-  [%sedlex.regexp? Plus ('0' .. '9' | 'a' .. 'z' | '.' | '_' | ':'), Star name]
+  [%sedlex.regexp? 'a' .. 'z', Plus ('0' .. '9' | 'a' .. 'z' | '.' | '_' | ':')]
 
 let id = [%sedlex.regexp? "$", Plus id_char]
 
@@ -126,7 +134,7 @@ let bad_num = [%sedlex.regexp? num, Plus id]
 
 let annot_atom =
   [%sedlex.regexp?
-    num | Plus (id_char | name) | ',' | ';' | '[' | ']' | '{' | '}']
+    Plus id_char | num | name | ',' | ';' | '[' | ']' | '{' | '}']
 
 let keywords =
   let tbl = Hashtbl.create 512 in
@@ -481,6 +489,7 @@ let rec token buf =
     let name = String.sub name 1 (String.length name - 2) in
     let name = mk_string buf name in
     NAME name
+  | "\"", Star string_elem -> raise Unclosed_string
   | eof -> EOF
   (* | "" -> EOF *)
   | any -> unknown_operator buf
@@ -492,14 +501,14 @@ and comment buf =
   | "(;" ->
     comment buf;
     comment buf
-  | eof -> Log.err "eof in comment"
+  | eof -> raise Unclosed_comment
   | any -> comment buf
   | _ -> assert false
 
 and single_comment buf =
   match%sedlex buf with
   | newline -> ()
-  | eof -> Log.err "eof in single line comment"
+  | eof -> raise Unclosed_comment
   | any -> single_comment buf
   | _ -> assert false
 
@@ -519,7 +528,8 @@ and annot buf =
   | annot_atom ->
     let annot_atom = Utf8.lexeme buf in
     Sexp.Atom annot_atom :: annot buf
-  | eof -> Log.err "eof in annotation"
+  | "\"", Star string_elem -> raise Unclosed_string
+  | eof -> raise Unclosed_annotation
   | any -> illegal_character buf
   | _ -> illegal_character buf
 
diff --git a/src/parser/text_lexer.mli b/src/parser/text_lexer.mli
index 9a6f6aef0..ead822180 100644
--- a/src/parser/text_lexer.mli
+++ b/src/parser/text_lexer.mli
@@ -9,11 +9,17 @@ exception Empty_annotation_id
 
 exception Empty_identifier
 
+exception Illegal_character of string
+
 exception Illegal_escape of string
 
-exception Unknown_operator of string
+exception Unclosed_annotation
 
-exception Illegal_character of string
+exception Unclosed_comment
+
+exception Unclosed_string
+
+exception Unknown_operator of string
 
 (** tokenizer *)
 val token : Sedlexing.lexbuf -> Text_parser.token
diff --git a/src/utils/result.ml b/src/utils/result.ml
index a81d7c832..ab2d57024 100644
--- a/src/utils/result.ml
+++ b/src/utils/result.ml
@@ -78,6 +78,9 @@ type err =
   | `Contract_unknown_func of Types.text Types.indice
   | `Empty_annotation_id
   | `Empty_identifier
+  | `Unclosed_annotation
+  | `Unclosed_comment
+  | `Unclosed_string
   ]
 
 type 'a t = ('a, err) Prelude.Result.t
@@ -169,3 +172,6 @@ let rec err_to_string = function
     Fmt.str "contract: unknown function %a" Types.pp_indice id
   | `Empty_annotation_id -> Fmt.str "empty annotation id"
   | `Empty_identifier -> Fmt.str "empty identifier"
+  | `Unclosed_annotation -> Fmt.str "unclosed annotation"
+  | `Unclosed_comment -> Fmt.str "unclosed comment"
+  | `Unclosed_string -> Fmt.str "unclosed string"
diff --git a/src/utils/result.mli b/src/utils/result.mli
index b25aaeb5d..90f63cf8c 100644
--- a/src/utils/result.mli
+++ b/src/utils/result.mli
@@ -78,6 +78,9 @@ type err =
   | `Contract_unknown_func of Types.text Types.indice
   | `Empty_annotation_id
   | `Empty_identifier
+  | `Unclosed_annotation
+  | `Unclosed_comment
+  | `Unclosed_string
   ]
 
 type 'a t = ('a, err) Prelude.Result.t