Unclear API for `Emitter` constructor

[Geod24]

D-YAML/source/dyaml/emitter.d

Lines 158 to 180 in 57c725a

	/**
	* Construct an emitter.
	*
	* Params: stream = Output range to write to.
	* canonical = Write scalars in canonical form?
	* indent = Indentation width.
	* lineBreak = Line break character/s.
	*/
	this(Range stream, const bool canonical, const int indent, const int width,
	const LineBreak lineBreak) @safe
	{
	states_.reserve(32);
	indents_.reserve(32);
	stream_ = stream;
	canonical_ = canonical;
	nextExpected!"expectStreamStart"();
	if(indent > 1 && indent < 10){bestIndent_ = indent;}
	if(width > bestIndent_ * 2) {bestWidth_ = width;}
	bestLineBreak_ = lineBreak;
	analysis_.flags.isNull = true;
	}

@WebFreaK remarked that (on L176):

why are the given in values ignored in other cases? shouldn't this rather be using contracts?

The parameters in question are not documented either.

[Herringway]

I have absolutely no idea... but I believe this library was either a pyyaml port or inspired by it, so the answer might be found there.