Re: How to read carriage return codes?

Hi Wouter

I understand that the 'hacky option'
...
set_stream(In, newline(posix))
...

should do.

bye Carlo



2013/7/30 Wouter Beek <[email protected]>

> Hi Carlo, Jan,
>
> Reading the stream as binary is indeed a good option, since it gives the
> exact same results as the Hex editor (not surprisingly). This is fine for
> my current use, so thanks a lot!
>
> Jan is right, loosing locale handling is sometimes a big drawback. Are
> newline handling and locate handling intertwined? I mean, would it be hard
> to have an option `newline(as_is)` and locate handling at the same time?
>
> ---
> Cheers!,
> Wouter.
>
> E-mail: [email protected]
> WWW: www.wouterbeek.com
> Tel.: 0647674624
>
>
> On Tue, Jul 30, 2013 at 1:54 PM, Jan Wielemaker <[email protected]>wrote:
>
>> On 07/30/2013 12:59 PM, Carlo Capelli wrote:
>>
>>> Hi Wouter
>>>
>>> I have this old code I used to transfer files with arbitrary encodings...
>>>
>>> copy_file(Source, Target) :- open(Source, read, S, [type(binary)]),
>>> open(Target, write, T, [type(binary)]), copy_stream_data(S, T), close(S),
>>> close(T).
>>>
>>
>> Not sure this is what Wouter is after.  Yes, one way to get the cr is
>> to open the file as binary.  That also stops interpreting character
>> locale handling (e.g., UTF-8 --> Unicode).  To accommodate handling
>> crlf files on POSIX platforms, there is a property called `newline'
>> attached to a stream.  You can do
>>
>>         open(File, read, In),
>>         set_stream(In, newline(posix)),
>>
>> which will stop newline translation.  Very hacky.  I can't really
>> imagine a scenario where you would like to do that.  Somewhat more
>> realistically might be
>>
>>         open(File, write, Out),
>>         set_stream(Out, newline(dos)),
>>
>> which will write \r\n at the end of each line regardless of the
>> operating system.
>>
>> The names posix and dos are a bit misleading.  Probably frustration
>> trying to make programs behave consistently in mixed Windows/Unix
>> environments :-(
>>
>>         Cheers --- Jan
>>
>>
>>  bye Carlo
>>>
>>>
>>>
>>> 2013/7/30 Wouter Beek <[email protected]>
>>>
>>>  Hi all,
>>>>
>>>> I want to read a file with CRLF line endings to a list of codes.
>>>> When I use open/3 and read_stream_to_codes/2 to do this the code list
>>>> only
>>>> has linefeeds (no carriage return).
>>>>
>>>> I'm probably overlooking something simple here... Is there a
>>>> setting/flag
>>>> to get the CR codes as well? I'm using 64bit Windows.
>>>>
>>>> The file as viewed in a Hex editor:
>>>> ~~~{.hex}
>>>> 0D 0A 0D 0A 0D 0A 0D 0A 0D 0A
>>>> ~~~
>>>>
>>>> The Prolog code:
>>>> ~~~
>>>> :- module(crlf, []).
>>>>
>>>> :- use_module(library(apply)).
>>>> :- use_module(library(readutil)).
>>>>
>>>> :- initialization(crlf).
>>>>
>>>> crlf:-
>>>>    source_file(crlf, ThisFile),
>>>>    file_directory_name(ThisFile, ThisDirectory),
>>>>    absolute_file_name(
>>>>      crlf,
>>>>      File,
>>>>      [access(read), extensions([txt]), relative_to(ThisDirectory)]
>>>>    ),
>>>>    open(File, read, Stream),
>>>>    read_stream_to_codes(Stream, Codes),
>>>>    maplist(writeln, Codes).
>>>> ~~~
>>>>
>>>> The output of the Prolog code:
>>>> ~~~
>>>> 10
>>>> 10
>>>> 10
>>>> 10
>>>> 10
>>>> ~~~
>>>>
>>>> ---
>>>> Cheers!,
>>>> Wouter.
>>>>
>>>> E-mail: [email protected]
>>>> WWW: www.wouterbeek.com
>>>> Tel.: 0647674624
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