scss-library/components/00_Global/_bemGenerator.styl

/*
 * This is set of mixins to help generating
 * CSS classes according to the Block__Element--Modifier pattern.
 * It also helps nesting those classes in any fashion imaganible
 * and still produces clean BEM CSS
 */
@import './_laneHandling'

_css-prefix = 'RV'
_global_scope = {
	_selector_blocks_to_generate: {}
	_element-modifier: ()
	_additional-element-modifier-blocks: ()
	_last_element_name: null
	_blocks_to_generate: ()
	_element_modifier_block_stack: ()
	_element_block_stack: ()
	_element_modifier_stack: {}
}

_block_building_lane = ()
_element_building_lange = ()

_work_lane(lane, callback)
	l = length(lane)
	for _ in (0..l)
		piece =  pop(lane)
		callback(piece)

/*
 * Gets the selector of the parent class
 */
_get_parent_selector()
	return split(' ', selector())[-1]


/*
 * Gets the selector of the current block
 */
_get_block_selector()
	return unquote(split('__', _get_parent_selector())[0])


_get_element_selector()
	element--modifier = split('__', _get_parent_selector())[1]
	return unquote(split('--', element--modifier)[0])


/*
 * Generates a CSS class for an
 * Block according to BEM
 */
RV-Block(block_name)
	b = @block{
		{block}
		& .{block_name}{
			for element_block in _pop_stack('elements_to_generate'){
				{element_block}
			}
		}
		
		&.{block_name}{
			for modifier_block in _pop_stack('block_modifiers_to_generate'){
				{modifier_block}
			}
		}
			
		for modifier_block in _pop_stack('after_element_modifiers_to_generate'){
			{modifier_block}
		}
		_reset_last_name('RV-Element')
		_reset_last_name('RV-Element__Modifier')
		_reset_last_name('RV-Block_Modifier')
	}
	
	if 'RV-Block' in called-from
		{b}
	else
		.{block_name}
			{b}

/*
 * Generates a CSS class for an block modifier
 * according to BEM. 
 */
RV-Block__Modifier(block_modifier_name)
	_push_onto_stack(block)
	
	//Detect if the selector will be generated
	//by an earlier call of RV-Block__Modifier
	if not 'RV-Block__Modifier' in called-from
		// Saving accumulated modifiers and blocks
		if 'RV-Block' in called-from
			elements = _pop_stack('block_modifier_elements_to_generate')
			modifier_block = @block{
				&--{block_modifier_name}{
					for sub_block in _pop_stack(){
						{sub_block}
					}
					& ^[-2..-2]{
						for	element in elements{
							{element}
						}
					}
					
				}
			}
			_push_onto_stack(modifier_block, 'block_modifiers_to_generate')


/*
 * Generates an CSS class for an element
 * according to BEM. Also minds the element modifiers
 * For more see RV-Element___Modifier
 */
RV-Element(element_name)
	_push_onto_stack(block)
	
	//Detect if the selector will be generated
	//by an earlier call of RV-Element
	if not 'RV-Element' in called-from
		// Saving accumulated modifiers and blocks
		stack_name = 'elements_to_generate'
		if 'RV-Block__Modifier' in called-from
			stack_name = 'block_modifier_elements_to_generate'

		element_block = @block{
			&__{element_name}{
				for sub_block in _pop_stack(){
					{sub_block}
				}
				
				&^[-3..-3]__{element_name}{
					for modifier_block in _pop_stack('element_modifiers_to_generate'){
						{modifier_block}
					}
				}
			}
		}
		
		_push_onto_stack(element_block, stack_name)
		_set_last_name(element_name)


/*
 * Generates a CSS class for an element modifier
 * according to BEM. These are ment to be part of the 
 * content block of an element and since child-mixins
 * are called first there is no way of knowing what the
 * current element is named. To solve this, we store
 * a callback for the modifier and add the element name
 * from RV-Element
 */
RV-Element__Modifier(element_modifier_name)
	_push_onto_stack(block)
	//Is this modifier beeing included by another modifier
	if not 'RV-Element__Modifier' in called-from
		//No, store all blocks under the give name
		//Is this modifier beeing called in in- or postfix
		if 'RV-Element' in called-from
			//Infix, store for handling by element
			modifier_block = @block{
				&--{element_modifier_name}{
					for current_block in _pop_stack(){
						{current_block}
					}
				}
			}
			
			_push_onto_stack(modifier_block, 'element_modifiers_to_generate')
		else
			//Postfix, append to existing element
			last_element_name = _get_last_name('RV-Element')
			modifier_block = @block {
				& .{block_name}__{last_element_name}.{block_name}__{last_element_name}--{element_modifier_name}{
					for current_block in _pop_stack(){
						{current_block}
					}
				}
			}
			_push_onto_stack(modifier_block, 'after_element_modifiers_to_generate')