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Message-Id: <D455E7DE-077E-49B0-8DFD-63468D90BC5D@gmail.com>
From: Joel Reymont <joelr1@gmail.com>
To: O'Caml Mailing List <caml-list@yquem.inria.fr>
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Subject: camlp4 stream parser and reporting error location
Date: Sat, 7 Mar 2009 11:23:47 +0000
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X-Spam: no; 0.00; camlp:01 parser:01 camlp:01 parser:01 ocamllex:01 lexer:01 'int:01 'string:01 bool:01 bool:01 ocaml:01 token:01 token:01 rec:01 int:01 

Assuming a simple Camlp4 parser that uses a ocamllex lexer wrapped in  
a stream,

let rec parse_primary = parser

   | [< 'INT n >] -> Int n
   | [< 'FLOAT n >] -> Float n
   | [< 'STRING n >] -> Str n
   | [< 'TRUE >] -> Bool true
   | [< 'FALSE >] -> Bool false

   | [< >] -> raise (Stream.Error "unknown token when expecting an  
expression.")

How do I report the error location?

Do I need to pass loc in with every token?

Then what happens in the error case where there's no token available?

	Thanks, Joel

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