# Look for an escape mark optionally associated with a label.
	# If a label is given, the escapemark of this label is returned.
	# If there is no label, the nearest escapemark that is `for loop` is returned.
	# If there is no valid escapemark, then an error is displayed ans null is returned.
	# Return null if no such a label is found.
	fun get_escapemark(node: ANode, nlabel: nullable ALabel): nullable EscapeMark
	do
		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: invalid anonymous label.")
					node.is_broken = true
					return null
				end
				return res
			end
			var name = nid.text
			var res = search_label(name)
			if res == null then
				self.error(nlabel, "Syntax Error: invalid label `{name}`.")
				node.is_broken = true
				return null
			end
			return res
		else
			for scope in scopes do
				var res = scope.escapemark
				if res != null then
					return res
				end
			end
			self.error(node, "Syntax Error: `break` statement outside block.")
			return null
		end
	end