diff --git a/src/passes/1-parser/cameligo.ml b/src/passes/1-parser/cameligo.ml
index ed0830312..8a4eb33f9 100644
--- a/src/passes/1-parser/cameligo.ml
+++ b/src/passes/1-parser/cameligo.ml
@@ -6,107 +6,93 @@ module ParserLog = Parser_cameligo.ParserLog
 module LexToken = Parser_cameligo.LexToken
 module Lexer = Lexer.Make(LexToken)
 
+module Errors = struct 
+
+  let lexer_error (e: Lexer.error AST.reg) =
+    let title () = "lexer error" in
+    let message () = Lexer.error_to_string e.value in
+    let data = [
+      ("parser_loc",
+       fun () -> Format.asprintf "%a" Location.pp_lift @@ e.region
+      )
+    ] in
+    error ~data title message
+
+  let parser_error start end_ = 
+    let title () = "parser error" in
+    let message () = "" in    
+    let loc = Region.make 
+      ~start:(Pos.from_byte start) 
+      ~stop:(Pos.from_byte end_) 
+    in
+    let data = [
+      ("parser_loc", 
+        fun () -> Format.asprintf "%a" Location.pp_lift @@ loc
+      )      
+    ] in
+    error ~data title message
+  
+  let unrecognized_error start end_ = 
+    let title () = "unrecognized error" in
+    let message () = "" in
+    let loc = Region.make 
+      ~start:(Pos.from_byte start) 
+      ~stop:(Pos.from_byte end_) 
+    in
+    let data = [
+      ("unrecognized_loc", 
+        fun () -> Format.asprintf "%a" Location.pp_lift @@ loc
+      )      
+    ] in
+    error ~data title message
+
+end
+
+open Errors
+
+type 'a parser = (Lexing.lexbuf -> LexToken.token) -> Lexing.lexbuf -> 'a
+
+let parse (parser: 'a parser) lexbuf = 
+  let Lexer.{read ; close ; _} = Lexer.open_token_stream None in
+  let result = 
+    try
+      ok (parser read lexbuf)
+    with
+      | Parser.Error ->
+        let start = Lexing.lexeme_start_p lexbuf in
+        let end_ = Lexing.lexeme_end_p lexbuf in
+        fail @@ (parser_error start end_)
+      | Lexer.Error e ->
+        fail @@ (lexer_error e)
+      | _ ->
+        let _ = Printexc.print_backtrace Pervasives.stdout in
+        let start = Lexing.lexeme_start_p lexbuf in
+        let end_ = Lexing.lexeme_end_p lexbuf in
+        fail @@ (unrecognized_error start end_)
+  in
+  close ();
+  result
+
 let parse_file (source: string) : AST.t result =
   let pp_input =
-      let prefix = Filename.(source |> basename |> remove_extension)
-      and suffix = ".pp.mligo"
-      in prefix ^ suffix in
+    let prefix = Filename.(source |> basename |> remove_extension)
+    and suffix = ".pp.mligo"
+    in prefix ^ suffix in
 
   let cpp_cmd = Printf.sprintf "cpp -traditional-cpp %s > %s"
-                                 source pp_input in
-   let%bind () = sys_command cpp_cmd in
+                               source pp_input in
+  let%bind () = sys_command cpp_cmd in
 
   let%bind channel =
     generic_try (simple_error "error opening file") @@
     (fun () -> open_in pp_input) in
   let lexbuf = Lexing.from_channel channel in
-  let Lexer.{read ; close ; _} =
-    Lexer.open_token_stream None in
-  specific_try (function
-      | Parser.Error -> (
-          let start = Lexing.lexeme_start_p lexbuf in
-          let end_ = Lexing.lexeme_end_p lexbuf in
-          let str = Format.sprintf
-              "Parse error at \"%s\" from (%d, %d) to (%d, %d). In file \"%s|%s\"\n"
-              (Lexing.lexeme lexbuf)
-              start.pos_lnum (start.pos_cnum - start.pos_bol)
-              end_.pos_lnum (end_.pos_cnum - end_.pos_bol)
-              start.pos_fname source
-          in
-          simple_error str
-        )
-      | exn ->
-          let start = Lexing.lexeme_start_p lexbuf in
-          let end_ = Lexing.lexeme_end_p lexbuf in
-          let str = Format.sprintf
-              "Unrecognized error (%s) at \"%s\" from (%d, %d) to (%d, %d). In file \"%s|%s\"\n"
-              (Printexc.to_string exn)
-              (Lexing.lexeme lexbuf)
-              start.pos_lnum (start.pos_cnum - start.pos_bol)
-              end_.pos_lnum (end_.pos_cnum - end_.pos_bol)
-              start.pos_fname source
-          in
-          simple_error str
-    ) @@ (fun () ->
-      let raw = Parser.contract read lexbuf in
-      close () ;
-      raw
-    ) >>? fun raw ->
-  ok raw
+  parse (Parser.contract) lexbuf
 
 let parse_string (s:string) : AST.t result =
   let lexbuf = Lexing.from_string s in
-  let Lexer.{read ; close ; _} =
-    Lexer.open_token_stream None in
-  specific_try (function
-      | Parser.Error -> (
-          let start = Lexing.lexeme_start_p lexbuf in
-          let end_ = Lexing.lexeme_end_p lexbuf in
-          let str = Format.sprintf
-              "Parse error at \"%s\" from (%d, %d) to (%d, %d)\n"
-              (Lexing.lexeme lexbuf)
-              start.pos_lnum (start.pos_cnum - start.pos_bol)
-              end_.pos_lnum (end_.pos_cnum - end_.pos_bol) in
-          simple_error str
-        )
-      | _ -> simple_error "unrecognized parse_ error"
-    ) @@ (fun () ->
-      let raw = Parser.contract read lexbuf in
-      close () ;
-      raw
-    ) >>? fun raw ->
-  ok raw
+  parse (Parser.contract) lexbuf
 
 let parse_expression (s:string) : AST.expr result =
-  let lexbuf = Lexing.from_string s in
-  let Lexer.{read ; close; _} =
-    Lexer.open_token_stream None in
-  specific_try (function
-      | Parser.Error -> (
-          let start = Lexing.lexeme_start_p lexbuf in
-          let end_ = Lexing.lexeme_end_p lexbuf in
-          let str = Format.sprintf
-              "Parse error at \"%s\" from (%d, %d) to (%d, %d)\n"
-              (Lexing.lexeme lexbuf)
-              start.pos_lnum (start.pos_cnum - start.pos_bol)
-              end_.pos_lnum (end_.pos_cnum - end_.pos_bol) in
-          simple_error str
-        )
-      | exn ->
-          let start = Lexing.lexeme_start_p lexbuf in
-          let end_ = Lexing.lexeme_end_p lexbuf in
-          let str = Format.sprintf
-              "Unrecognized error (%s) at \"%s\" from (%d, %d) to (%d, %d). In expression \"%s|%s\"\n"
-              (Printexc.to_string exn)
-              (Lexing.lexeme lexbuf)
-              start.pos_lnum (start.pos_cnum - start.pos_bol)
-              end_.pos_lnum (end_.pos_cnum - end_.pos_bol)
-              start.pos_fname s
-          in
-          simple_error str
-    ) @@ (fun () ->
-      let raw = Parser.interactive_expr read lexbuf in
-      close () ;
-      raw
-    ) >>? fun raw ->
-  ok raw
+  let lexbuf = Lexing.from_string s in  
+  parse (Parser.interactive_expr) lexbuf
\ No newline at end of file
diff --git a/src/passes/1-parser/pascaligo.ml b/src/passes/1-parser/pascaligo.ml
index 62d56ab8b..05c0af4df 100644
--- a/src/passes/1-parser/pascaligo.ml
+++ b/src/passes/1-parser/pascaligo.ml
@@ -6,6 +6,73 @@ module ParserLog = Parser_pascaligo.ParserLog
 module LexToken = Parser_pascaligo.LexToken
 module Lexer = Lexer.Make(LexToken)
 
+module Errors = struct 
+
+  let lexer_error (e: Lexer.error AST.reg) =
+    let title () = "lexer error" in
+    let message () = Lexer.error_to_string e.value in
+    let data = [
+      ("parser_loc",
+       fun () -> Format.asprintf "%a" Location.pp_lift @@ e.region
+      )
+    ] in
+    error ~data title message
+
+  let parser_error start end_ = 
+    let title () = "parser error" in
+    let message () = "" in    
+    let loc = Region.make 
+      ~start:(Pos.from_byte start) 
+      ~stop:(Pos.from_byte end_) 
+    in
+    let data = [
+      ("parser_loc", 
+        fun () -> Format.asprintf "%a" Location.pp_lift @@ loc
+      )      
+    ] in
+    error ~data title message
+  
+  let unrecognized_error start end_ = 
+    let title () = "unrecognized error" in
+    let message () = "" in
+    let loc = Region.make 
+      ~start:(Pos.from_byte start) 
+      ~stop:(Pos.from_byte end_) 
+    in
+    let data = [
+      ("unrecognized_loc", 
+        fun () -> Format.asprintf "%a" Location.pp_lift @@ loc
+      )      
+    ] in
+    error ~data title message
+
+end
+
+open Errors
+
+type 'a parser = (Lexing.lexbuf -> LexToken.token) -> Lexing.lexbuf -> 'a
+
+let parse (parser: 'a parser) lexbuf = 
+  let Lexer.{read ; close ; _} = Lexer.open_token_stream None in
+  let result = 
+    try
+      ok (parser read lexbuf)
+    with
+      | Parser.Error ->
+        let start = Lexing.lexeme_start_p lexbuf in
+        let end_ = Lexing.lexeme_end_p lexbuf in
+        fail @@ (parser_error start end_)
+      | Lexer.Error e ->
+        fail @@ (lexer_error e)
+      | _ ->
+        let _ = Printexc.print_backtrace Pervasives.stdout in
+        let start = Lexing.lexeme_start_p lexbuf in
+        let end_ = Lexing.lexeme_end_p lexbuf in
+        fail @@ (unrecognized_error start end_)
+  in
+  close ();
+  result
+
 let parse_file (source: string) : AST.t result =
   let pp_input =
     let prefix = Filename.(source |> basename |> remove_extension)
@@ -20,93 +87,12 @@ let parse_file (source: string) : AST.t result =
     generic_try (simple_error "error opening file") @@
     (fun () -> open_in pp_input) in
   let lexbuf = Lexing.from_channel channel in
-  let Lexer.{read ; close ; _} =
-    Lexer.open_token_stream None in
-  specific_try (function
-      | Parser.Error -> (
-          let start = Lexing.lexeme_start_p lexbuf in
-          let end_ = Lexing.lexeme_end_p lexbuf in
-          let str = Format.sprintf
-              "Parse error at \"%s\" from (%d, %d) to (%d, %d). In file \"%s|%s\"\n"
-              (Lexing.lexeme lexbuf)
-              start.pos_lnum (start.pos_cnum - start.pos_bol)
-              end_.pos_lnum (end_.pos_cnum - end_.pos_bol)
-              start.pos_fname source
-          in
-          simple_error str
-        )
-      | exn ->
-          let start = Lexing.lexeme_start_p lexbuf in
-          let end_ = Lexing.lexeme_end_p lexbuf in
-          let str = Format.sprintf
-              "Unrecognized error (%s) at \"%s\" from (%d, %d) to (%d, %d). In file \"%s|%s\"\n"
-              (Printexc.to_string exn)
-              (Lexing.lexeme lexbuf)
-              start.pos_lnum (start.pos_cnum - start.pos_bol)
-              end_.pos_lnum (end_.pos_cnum - end_.pos_bol)
-              start.pos_fname source
-          in
-          simple_error str
-    ) @@ (fun () ->
-      let raw = Parser.contract read lexbuf in
-      close () ;
-      raw
-    ) >>? fun raw ->
-  ok raw
+  parse (Parser.contract) lexbuf
 
 let parse_string (s:string) : AST.t result =
   let lexbuf = Lexing.from_string s in
-  let Lexer.{read ; close ; _} =
-    Lexer.open_token_stream None in
-  specific_try (function
-      | Parser.Error -> (
-          let start = Lexing.lexeme_start_p lexbuf in
-          let end_ = Lexing.lexeme_end_p lexbuf in
-          let str = Format.sprintf
-              "Parse error at \"%s\" from (%d, %d) to (%d, %d)\n"
-              (Lexing.lexeme lexbuf)
-              start.pos_lnum (start.pos_cnum - start.pos_bol)
-              end_.pos_lnum (end_.pos_cnum - end_.pos_bol) in
-          simple_error str
-        )
-      | _ -> simple_error "unrecognized parse_ error"
-    ) @@ (fun () ->
-      let raw = Parser.contract read lexbuf in
-      close () ;
-      raw
-    ) >>? fun raw ->
-  ok raw
+  parse (Parser.contract) lexbuf
 
 let parse_expression (s:string) : AST.expr result =
-  let lexbuf = Lexing.from_string s in
-  let Lexer.{read ; close; _} =
-    Lexer.open_token_stream None in
-  specific_try (function
-      | Parser.Error -> (
-          let start = Lexing.lexeme_start_p lexbuf in
-          let end_ = Lexing.lexeme_end_p lexbuf in
-          let str = Format.sprintf
-              "Parse error at \"%s\" from (%d, %d) to (%d, %d)\n"
-              (Lexing.lexeme lexbuf)
-              start.pos_lnum (start.pos_cnum - start.pos_bol)
-              end_.pos_lnum (end_.pos_cnum - end_.pos_bol) in
-          simple_error str
-        )
-      | exn ->
-          let start = Lexing.lexeme_start_p lexbuf in
-          let end_ = Lexing.lexeme_end_p lexbuf in
-          let str = Format.sprintf
-              "Unrecognized error (%s) at \"%s\" from (%d, %d) to (%d, %d). In expression \"%s|%s\"\n"
-              (Printexc.to_string exn)
-              (Lexing.lexeme lexbuf)
-              start.pos_lnum (start.pos_cnum - start.pos_bol)
-              end_.pos_lnum (end_.pos_cnum - end_.pos_bol)
-              start.pos_fname s
-          in
-          simple_error str
-    ) @@ (fun () ->
-      let raw = Parser.interactive_expr read lexbuf in
-      close () ;
-      raw
-    ) >>? fun raw ->
-  ok raw
+  let lexbuf = Lexing.from_string s in  
+  parse (Parser.interactive_expr) lexbuf