FormatOutput

A bridge between a Layout instance and a stream. This is used for the Stdout & Stderr globals, but can be used for general purpose buffer-formatting as desired. The Template type 'T' dictates the text arrangement within the target buffer ~ one of char, wchar or dchar (UTF8, UTF16, or UTF32).

FormatOutput exposes this style of usage:

auto print = new FormatOutput!(char) (...);

print ("hello");                    // => hello
print (1);                          // => 1
print (3.14);                       // => 3.14
print ('b');                        // => b
print (1, 2, 3);                    // => 1, 2, 3
print ("abc", 1, 2, 3);             // => abc, 1, 2, 3
print ("abc", 1, 2) ("foo");        // => abc, 1, 2foo
print ("abc") ("def") (3.14);       // => abcdef3.14

print.format ("abc {}", 1);         // => abc 1
print.format ("abc {}:{}", 1, 2);   // => abc 1:2
print.format ("abc {1}:{0}", 1, 2); // => abc 2:1
print.format ("abc ", 1);           // => abc

Note that the last example does not throw an exception. There are several use-cases where dropping an argument is legitimate, so we're currently not enforcing any particular trap mechanism.

Flushing the output is achieved through the flush() method, or via an empty pair of parens:

print ("hello world") ();
print ("hello world").flush;

print.format ("hello {}", "world") ();
print.format ("hello {}", "world").flush;

Special character sequences, such as "\n", are written directly to the output without any translation (though an output-filter could be inserted to perform translation as required). Platform-specific newlines are generated instead via the newline() method, which also flushes the output when configured to do so:

print ("hello ") ("world").newline;
print.format ("hello {}", "world").newline;
print.formatln ("hello {}", "world");

The format() method supports the range of formatting options exposed by tango.text.convert.Layout and extensions thereof; including the full I18N extensions where configured in that manner. To create a French instance of FormatOutput:

import tango.text.locale.Locale;

auto locale = new Locale (Culture.getCulture ("fr-FR"));
auto print = new FormatOutput!(char) (locale, ...);

Note that FormatOutput is *not* intended to be thread-safe.