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

// Storing the currents block properties and attributes
// to generate the block afterwards
/*
 * A method for iterating throug a 
 * list/array safely since this language sucks
 * realy bad https://github.com/stylus/stylus/issues/1440
 */
foreach(list, callback)
	for entry in list
		if entry != ()
			callback(entry)

create_list()
	return () ()

_block = {}
reset_block()
	_block.elements = create_list()
	_block.block_modifiers = create_list()
	_block.alias = {
		map: {}
		stash: {
			RV-Element: create_list()
			RV-Element__Modifier: create_list()
			RV-Block__Modifier: create_list()
		}
	}
	_block.modifier_stash = create_list()
	_block.element_stash = create_list()

// Calling the function to initiate the block
// for first use
reset_block()

_bem_mixins = 'RV-Block','RV-Element','RV-Modifier','RV-Element__Modifier','RV-Block__Modifier'

/*
 * Checks if the caller of this funcion is a direct
 * descendant of RV-Block. Checks for BEM-Mixins only.
 * If any other function or mixin is between the last 
 * block and the caller, it will still count as an direct
 * descendant of RV-Block
 */
is_direct_descendant_of_block()
	block_index = index(called-from, 'RV-Block') - 1
	
	if block_index <= 0
		return true
	
	for i in (1..block_index)
		if called-from[i] in _bem_mixins
			return false
	return true

/*
 * Checks if we are called inside a block
 */
is_in_block()
	return 'RV-Block' in called-from

/* 
 * Taking the currently stashed names, mapping
 * them to the given name under the called parent
 * (using called-from) and returning the stashed blocks
 */
generate_aliases(actual_name, level_type=null)
	if level_type == null
		level_type = split(' ', called-from)[0]
	if actual_name == null
		if length(_block.alias.stash[level_type]) > 2
			actual_name = _block.alias.stash[level_type][-1].name
		else
			warn('No name found for '+called-from)

	blocks = ()
	foreach(_block.alias.stash[level_type], @(alias){
		_block.alias.map[level_type+':'+alias.name] = actual_name
		push(blocks, alias.block)
	})
	
	_block.alias.stash[level_type] = create_list()
	return {
		name: actual_name
		blocks: blocks
	}

/*
 * Resolving the alias according to the level type
 * (using called-from). Returning the given name
 * when no alias is found
 */
resolve_alias(name, level_type=null)
	if level_type == null
		level_type = split(' ', called-from)[0]
	
	if level_type+':'+name in _block.alias.map
		return _block.alias.map[level_type+':'+name]
	else
		return name

/*
 * Renders an element modifier
 */
render_element_modifier(modifier)
	&--{resolve_alias(modifier.name, 'RV-Element__Modifier')}
		foreach(modifier.blocks, @(block){
			{block}
		})

/*
 * Renders an element
 */
render_element(element)
	&__{resolve_alias(element.name, 'RV-Element')}
		foreach(element.blocks, @(block){
			{block}
		})
		foreach(element.modifiers, @(modifier){
			render_element_modifier(modifier)
		})

/*
 * Renders an block modifier, 
 */
render_block_modifier(modifier)
	&--{resolve_alias(modifier.name, 'RV-Block__Modifier')}
		foreach(modifier.blocks, @(block){
			{block}
		})
		& ^[-2..-2]{
			foreach(modifier.elements, @(element){
				render_element(element)
			})
		}	


RV-Squash()
	{block}

/*
 * Stashing the given block under the given
 * name to be aliased by a late level
 * (See generate_aliases)
 */
RV-Element--name(name)
	if 'RV-Squash' in called-from
		{block}
	else
		if 'RV-Element' in called-from
			push(_block.alias.stash.RV-Element, {
				name: name
				block: block
			})
		else
			{block}

RV-Element__Modifier--name(name)
	if 'RV-Squash' in called-from
		{block}
	else
		if 'RV-Element__Modifier' in called-from
			push(_block.alias.stash.RV-Element__Modifier, {
				name: name
				block: block
			})
		else
			{block}
	
RV-Block__Modifier--name(name)
	if 'RV-Squash' in called-from
		{block}
	else
		if 'RV-Block__Modifier' in called-from
			push(_block.alias.stash.RV-Block__Modifier, {
				name: name
				block: block
			})
		else
			{block}


RV-Block(block_name)
	& .{block_name}
		{block}
		foreach(_block.block_modifiers, @(modifier){
			render_block_modifier(modifier)
		})
		foreach(_block.elements, @(element){
			render_element(element)
		})
		
	reset_block()


RV-Block__Modifier(modifier_name=null)
	if 'RV-Squash' in called-from
		{block}
	else
		blocks = generate_aliases(modifier_name)
		modifier_name = blocks.name
		blocks = blocks.blocks
		push(blocks, block)
		
		modifier = {
			name: modifier_name
			blocks: blocks
			elements: _block.element_stash
		}
		_block.element_stash = create_list()
		
		push(_block.block_modifiers, modifier)

RV-Element(element_name=null)
	if 'RV-Squash' in called-from
		{block}
	else
		blocks = generate_aliases(element_name)

		element_name = blocks.name
		blocks = blocks.blocks
		push(blocks, block)
		
		element = {
			name: element_name
			blocks: blocks
			modifiers: _block.modifier_stash
		}
		_block.modifier_stash = create_list()
		
		if is_direct_descendant_of_block()
			push(_block.elements, element)
		else
			push(_block.element_stash, element)


RV-Element__Modifier(modifier_name=null)
	if 'RV-Squash' in called-from
		{block}
	else
		blocks = generate_aliases(modifier_name)
		modifier_name = blocks.name
		blocks = blocks.blocks
		push(blocks, block)
		
		modifier = {
			name: modifier_name
			blocks: blocks
		}
		push(_block.modifier_stash, modifier)