[phobos] Transcoded text stdio

[Shin Fujishiro]

Hello,

I'm trying to integrate codeset conversion facility to std.stdio.
But how can it be done?

Mixing transcoded and non-transcoded (UTF-8) I/O in the same File
structure will mess up the source.  I think separating UTF-8 based I/O
and transcoded I/O is necessary.

I could think of the following four ways.

1.  Integrate everything in the File anyway.

2.  Make the File to always perform conversion.

3.  Create a distinct type for transcoded I/O.
----------
    shared TranscodedFile stdout;
    stdout.writeln("Hallå, Värld!");
----------
# http://github.com/sinfu/misc/blob/master/stdio/test01.d

4.  Simplify the File and define upper layer structures.
----------
    // File itself doesn't provide byLine etc.
    shared File stdout;

    // these 'ports' perform actual I/O for specific purposes
    shared UTF8TextIOPort stdoutUTF8;
    shared NativeTextIOPort stdoutText;
    shared BinaryIOPort stdoutBin;

    // wrap stdout with various 'I/O ports'
    stdoutUTF8 = UTF8TextIOPort(stdout);
    stdoutText = NativeTextIOPort(stdout);
    stdoutBin = BinaryIOPort(stdout);

    // write text in UTF-8
    stdoutUTF8.writeln("Hallå, Värld!");

    // write text in console encoding
    stdoutText.writeln("Hallå, Värld!");

    // free functions use stdoutText
    writeln("Hallå, Värld!");
----------
# http://github.com/sinfu/misc/blob/master/stdio/test02.d

...

I'm uncertain of which is the best.  Perhaps there are more reasonable
ways.  What do you think?  Any ideas?


Thanks,
Shin