Re: [Caml-list] Escaped string in sexplib

[Hugo Ferreira <hmf@inescporto.pt>]

Török Edwin wrote:
> On 06/08/2010 09:52 PM, Hugo Ferreira wrote:
>> Hello,
>>
>> Markus Mottl wrote:
>>> On Tue, Jun 8, 2010 at 11:44, Hugo Ferreira <hmf@inescporto.pt> wrote:
>>>> I am trying to us the Sexplib library to process data.
>>>> However I am having some trouble with strings.
>>>> Specifically I need to save and restore strings to a file
>>>> so that the escaping done during saving is "undone"
>>>> when data is read back in.
>>>>
>>>> How can I do this? Appreciate any pointers.
>>> The I/O and parsing routines in the S-expression library should take
>>> care of escaped strings just fine.  
>> My apologies but I did not explain myself correctly. The problem here is
>> that I am trying to automate the conversion to string of the data
>> structure read from the s-expressions. I have the following:
>>
>> let string_of_experiment_data data =
>>   let data = sexp_of_experiment_data data in
>>   Sexplib.Sexp.to_string_hum data
>>
>> The problem here is that the "to_string_hum" escapes certain characters,
>> but I need to have the strings "not escaped". So my question is: is
>> their any way I can tell sexplib to output a string but not escape
>> it? Otherwise I will have to hand encode this stuff 8-(
>>
>>> Btw., the escaping conventions are
>>> absolutely identical to the ones used by OCaml.
>>>
>> I am aware of this as it is indicated in your documentation and
>> the ocaml tutorial site. I also searched for a means to "unescape"
>> the result from "to_string_hum", which would also work. However
>> I cannot find a String.unescape. This issue has already been pointed
>> out. A possible solution would be to use the old.
>>
>>  Token.eval_string
>>
>> and I cannot seem to use the equivalent of the new camlp4. The
>> equivalent:
>>
>> open Camlp4.PreCast
>> open Syntax
>> let eval_string s = Camlp4.Struct.Token.Eval.string ~strict:() s
>>
>> does not compile (Error: Unbound module Camlp4.PreCast).
> 
> It compiles for me if I add -I +camlp4:
> ocamlc -I +camlp4 -c x.ml
> or:
> ocamlfind ocamlc -package camlp4.lib -c x.ml
> 
> It also links if you add -linkpkg.
> 

Correct. I had forgotten to add the relevant
tags to the ocamlbuild file. The following works
for me:

<src/ilp/experiment.*>: use_camlp4, use_dynlink

Thanks,
Hugo F.


> Best regards,
> --Edwin
> 
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