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.

FormatOutput exposes this style of usage:

auto print = new FormatOutput(...);

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:

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

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

class FormatOutput : OutputFilter {

alias flush = OutputFilter.flush;

alias nl = newline;

protected static immutable

auto Eol;

this(OutputStream output, cstring eol);

typeof(this) format(cstring fmt, Args args);

typeof(this) formatln(cstring fmt, Args args);

FormatOutput newline();

FormatOutput flush(bool yes);

OutputStream stream();

FormatOutput stream(OutputStream output);

void emit(cstring s);

}

Constructors

this this(OutputStream output, cstring eol): Construct a FormatOutput instance, tying the provided stream to a layout formatter.

Members

Aliases

flush alias flush = OutputFilter.flush: Undocumented in source.
nl alias nl = newline: Undocumented in source.

Functions

emit void emit(cstring s): Sink for passing to the formatter.
flush FormatOutput flush(bool yes): Control implicit flushing of newline(), where true enables flushing. An explicit flush() will always flush the output.
format typeof(this) format(cstring fmt, Args args): Format the provided arguments to the stream according to the format string
formatln typeof(this) formatln(cstring fmt, Args args): Format the provided arguments to the stream according to the format string, and append a newline to the output.
newline FormatOutput newline(): Output a newline and optionally flush.
stream OutputStream stream(): Return the associated output stream.
stream FormatOutput stream(OutputStream output): Set the associated output stream.

Static variables

Eol auto Eol;: Undocumented in source.

Inherited Members

From OutputFilter

sink OutputStream sink;: Undocumented in source.
conduit IConduit conduit(): Return the hosting conduit.
write size_t write(const(void)[] src): Write to conduit from a source array. The provided src content will be written to the conduit.
copy OutputStream copy(InputStream src, size_t max): Transfer the content of another conduit to this one. Returns a reference to this class, or throws IOException on failure.
flush IOStream flush(): Emit/purge buffered content.
seek long seek(long offset, Anchor anchor): Seek on this stream. Target conduits that don't support seeking will throw an IOException.
output OutputStream output(): Return the upstream host of this filter.
close void close(): Close the output.