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
 */

_css-prefix = 'RV'
_element-modifier = ()
_additional-element-modifier-blocks = ()

/*
 * 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()
	p(_get_parent_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(name)
	.{_css-prefix}-{name}
		{block}
	
/*
 * Generates a CSS class for an block modifier
 * according to BEM. 
 */
RV-Block__Modifier(name)
	if 'RV-Block__Modifier' in called-from
		{block}
	else
		&{_get_block_selector()}--{name}
			{block}

_create_element(name, block)
	{block}
	// Checking for modifiers
	l = length(_element-modifier) - 1
	for i in range(0, l)
		modifier = pop(_element-modifier)
		callback = modifier['callback']
		// Calling the modifiers block,
		// passing the name of the element
		callback(
			element: name,
			name: modifier['name'],
			block_list: modifier['block_list']
		)
		

/*
 * Generates an CSS class for an element
 * according to BEM. Also minds the element modifiers
 * For more see RV-Element___Modifier
 */
RV-Element(name)	
	block-selector = _get_block_selector()
	// Are we in a block?
	if block-selector != '&'
		//Create Selector and output the CSS for the element
		
		//Detect if the selector will be generated
		//by an earlier call of RV-Element
		if 'RV-Element' in called-from
			_create_element(name, block)
		else
			{block-selector}__{name}
				_create_element(name, block)
	else
		warn('No block found. Creating One instead')
		+RV-Block(name)
			{block}
/*
 * 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(name)
	if 'RV-Element__Modifier' in called-from
		//What the actual fuch this language is to utterly buggy
		push(_additional-element-modifier-blocks, @block{block})
	else
		callback = @(element, name, block_list){
			&{_get_block_selector()}__{element}--{name}{
				for current_block in block_list{
					
					{current_block}
				}
			}
		}
		block_list = ()
		push(block_list, @block{block})
		l = length(_additional-element-modifier-blocks)
		for i in range(0, l)
			b = pop(_additional-element-modifier-blocks)
			push(block_list, b)
	
		push(_element-modifier, {
			callback: callback
			name: name 
			block_list: block_list,
		})