# Create a new escape mark (possibly with a label)
	# Display an error on toolcontext if a label with the same name is masked.
	fun make_escape_mark(nlabel: nullable ALabel, for_loop: Bool): EscapeMark
	do
		var name: nullable String
		if nlabel != null then
			var nid = nlabel.n_id
			if nid == null then
				var res = search_label("")
				if res != null then
					self.error(nlabel, "Syntax Error: anonymous label already defined.")
				end
				name = ""
			else
				name = nid.text
				var found = self.search_label(name)
				if found != null then
					self.error(nlabel, "Syntax Error: label `{name}` already defined.")
				end
			end
		else
			name = null
		end
		var res = new EscapeMark(name)
		if for_loop then res.continue_mark = new EscapeMark(name)
		return res
	end