diff --git a/src/passes/1-parser/cameligo/.unlexer.tag b/src/passes/1-parser/cameligo/.unlexer.tag
new file mode 100644
index 000000000..e69de29bb
diff --git a/src/passes/1-parser/cameligo/dune b/src/passes/1-parser/cameligo/dune
index 0c9e80bf0..d882434df 100644
--- a/src/passes/1-parser/cameligo/dune
+++ b/src/passes/1-parser/cameligo/dune
@@ -2,15 +2,13 @@
 
 (menhir
  (merge_into Parser)
- (modules
-    ParToken Parser)
+ (modules ParToken Parser)
  (flags -la 1 --table --strict --explain --external-tokens LexToken))
 
 (library
  (name parser_cameligo)
  (public_name ligo.parser.cameligo)
- (modules
-    AST cameligo Parser ParserLog LexToken)
+ (modules AST cameligo Parser ParserLog LexToken)
  (libraries
    menhirLib
    parser_shared
@@ -22,18 +20,18 @@
 
 (executable
   (name LexerMain)
-  (libraries
-     parser_cameligo)
-  (modules
-     LexerMain)
+  (libraries parser_cameligo)
+  (modules LexerMain)
   (flags (:standard -open Parser_shared -open Parser_cameligo)))
 
 (executable
   (name ParserMain)
-  (libraries
-     parser_cameligo)
+  (libraries parser_cameligo)
   (modules
-     ParErr
-     ParserAPI
-     ParserMain)
+     ParErr ParserAPI ParserMain)
   (flags (:standard -open Simple_utils -open Parser_shared -open Parser_cameligo)))
+
+(executable
+  (name Unlexer)
+  (libraries str)
+  (modules Unlexer))
diff --git a/src/passes/1-parser/cameligo/unlexer.ml b/src/passes/1-parser/cameligo/unlexer.ml
new file mode 100644
index 000000000..1d4ac5fef
--- /dev/null
+++ b/src/passes/1-parser/cameligo/unlexer.ml
@@ -0,0 +1,109 @@
+(** Converting the textual representation of tokens produced by Menhir
+    into concrete syntax *)
+
+(* See [ParToken.mly] *)
+
+let gen_sym prefix =
+  let count = ref 0 in
+  fun () -> incr count;
+         prefix ^ string_of_int !count
+
+let id_sym   = gen_sym "id"
+and ctor_sym = gen_sym "C"
+
+let concrete = function
+  (* Keywords *)
+
+| "Begin" -> "begin"
+| "Else"  -> "else"
+| "End"   -> "end"
+| "False" -> "false"
+| "Fun"   -> "fun"
+| "If"    -> "if"
+| "In"    -> "in"
+| "Let"   -> "let"
+| "Match" -> "match"
+| "Mod"   -> "mod"
+| "Not"   -> "not"
+| "Of"    -> "of"
+| "Or"    -> "or"
+| "Then"  -> "then"
+| "True"  -> "true"
+| "Type"  -> "type"
+| "With"  -> "with"
+
+  (* Data constructors *)
+
+| "C_None"   -> "None"
+| "C_Some"   -> "Some"
+
+  (* Symbols *)
+
+| "MINUS"    -> "-"
+| "PLUS"     -> "+"
+| "SLASH"    -> "/"
+| "TIMES"    -> "*"
+
+| "LPAR"     -> "("
+| "RPAR"     -> ")"
+| "LBRACKET" -> "["
+| "RBRACKET" -> "]"
+| "LBRACE"   -> "{"
+| "RBRACE"   -> "}"
+
+| "ARROW"    -> "->"
+| "CONS"     -> "::"
+| "CAT"      -> "^"
+| "DOT"      -> "."
+
+| "COMMA"    -> ","
+| "SEMI"     -> ";"
+| "COLON"    -> ":"
+| "VBAR"     -> "|"
+
+| "WILD"     -> "_"
+
+| "EQ"       -> "="
+| "NE"       -> "<>"
+| "LT"       -> "<"
+| "GT"       -> ">"
+| "LE"       -> "<="
+| "GE"       -> ">="
+
+| "BOOL_OR"  -> "||"
+| "BOOL_AND" -> "&&"
+
+  (* Literals *)
+
+| "String"   -> "\"a string\""
+| "Bytes"    -> "0xAA"
+| "Int"      -> "1"
+| "Nat"      -> "1n"
+| "Mutez"    -> "1mutez"
+| "Ident"    -> id_sym ()
+| "Constr"   -> ctor_sym ()
+
+  (* Virtual tokens *)
+
+| "EOF"      -> ""
+
+  (* For completeness of open sum types *)
+
+| _          -> "<Unknown>"
+
+(* Unlexing a sentence *)
+
+let unlex (sentence: string) : Buffer.t =
+  let tokens  = Str.split (Str.regexp " ") sentence in
+  let lexemes = List.map concrete tokens in
+  let buffer  = Buffer.create 31 in
+  let rec trans = function
+      [] -> ()
+  |  [s] -> Buffer.add_string buffer s
+  | s::l -> Buffer.add_string buffer (s ^ " "); trans l
+  in trans lexemes; buffer
+
+(* Reading one line from the standard input channel and unlex it. *)
+
+let out = unlex (input_line stdin) |> Buffer.contents
+let ()  = Printf.printf "%s\n" out
diff --git a/vendors/ligo-utils/simple-utils/cover.sh b/vendors/ligo-utils/simple-utils/cover.sh
index 01281ef6d..b7331dd37 100755
--- a/vendors/ligo-utils/simple-utils/cover.sh
+++ b/vendors/ligo-utils/simple-utils/cover.sh
@@ -111,8 +111,8 @@ done
 usage () {
   cat <<EOF
 Usage: $(basename $0) [-h|--help]
-                --par-tokens=<par_tolens>.mly
-                --lex-tokens=<par_tokens>.mli
+                --par-tokens=<par_tokens>.mly
+                --lex-tokens=<lex_tokens>.mli
                 --unlexer=<binary>
                 --ext=<extension>
                 --dir=<path>
@@ -121,7 +121,7 @@ Usage: $(basename $0) [-h|--help]
 Generates in directory <path> a set of LIGO source files with
 extension <extension> covering all erroneous states of the LR
 automaton produced by Menhir from <parser>.mly, <par_tokens>.mly,
-<lex_tokens>.mli and <parser>.msg (see script `messages.sh` for
+<lex_tokens>.mli and <parser>.msg (see script messages.sh for
 generating the latter). The LIGO files will be numbered with their
 corresponding state number in the automaton. The executable <binary>
 reads a line on stdin of tokens and produces a line of corresponding