Story

When I refactor LanguageConverter I want to avoid overriding constructors by children, so I can easily add/remove new arguments without changing code for all classes in the hierarchy.

Context

At the moment LanguageConverter:: __construct takes too many arguments:

public function __construct( $langobj, $maincode, $variants = [],
							$variantfallbacks = [], $flags = [],
							$manualLevel = [] ) {
...

Most of them (except $langobj) are constant and injected by inheritors:

class EnConverter extends LanguageConverter {

	public function __construct( $langobj ) {
		parent::__construct( $langobj, 'en', [ 'en', 'en-x-piglatin' ] );
	}
...

As a possible solution, the idea is to turn such variables into protected getters overridden by inheritors. This will move a significant part of the logic to that constructors and make it possible not to override it.

Expected Result

1. Turn $maincode, $variants, $variantfallbacks, $flags, $manualLevel into getters
2. Override getters in inheritors of LanguageConverter
3. Avoid overriding the constructor of inheritors when add/remove new argument.