Convert attributes to HTML tags

attrs2html.py

class Element():
	closable = True
	mergeable = True

class Italic(Element):
	tag = 'i'

class Bold(Element):
	tag = 'b'

class Underlined(Element):
	tag = 'u'

class Anchor(Element):
	tag = 'a'
	mergeable = False
	
class Color(Element):
	tag = 'color'
	mergeable = False

class Br(Element):
	tag = 'br'
	closable = False

class Converter:

	def __init__(self):
		self.output = []
		self.opened_elems = []

	def _open(self, elem):
		self.output.append('<' + elem.tag + '>')
		self.opened_elems.append(elem)
		if not elem.closable:
			self._remove(elem)

	def _close(self, elem):
		for opened_elem in reversed(self.opened_elems):
			if opened_elem.closable:
				self.output.append('</' + opened_elem.tag + '>')
			self._remove(opened_elem)
			if opened_elem == elem:
				break
		
	def _remove(self, elem):
		# Remove last (most recently added) occurence
		self.opened_elems.reverse()
		self.opened_elems.remove(elem)
		self.opened_elems.reverse()

	def convert(self, input):
		self.output = []
		self.opened_elems = []

		for elems in input:
			# Close elements from previous iteration
			for opened_elem in reversed(self.opened_elems):
				if not opened_elem.mergeable or opened_elem not in elems:
					self._close(opened_elem)

			# Open new elements
			for elem in elems:
				if not elem.mergeable or not elem in self.opened_elems:
					self._open(elem)

		# Close remaining elements
		for opened_elem in reversed(self.opened_elems):
			self._close(opened_elem)

		return self.output

def main():
	inputs = [
		[[Bold, Anchor, Underlined], [Bold, Underlined]],
		# ['<b>', '<a>', '<u>', '</u>', '</a>', '<u>', '</u>', '</b>']

		[[Anchor, Bold, Color, Color], [Bold, Color]],
		# ['<a>', '<b>', '<color>', '<color>', '</color>', '</color>', '</b>', '</a>', '<b>', '<color>', '</color>', '</b>']
	]

	for input in inputs:
		output = Converter().convert(input)
		print(output)

if __name__ == '__main__':
	main()