# A VSM index to store strings
class StringIndex
	super VSMIndex

	# Index a new Document from `title`, `uri` and string `string`.
	#
	# Return the Document created.
	#
	# See `index_document`.
	fun index_string(title, uri, string: String, auto_update: nullable Bool): DOC do
		var vector = parse_string(string)
		var doc = new Document(title, uri, vector)
		index_document(doc, auto_update)
		return doc
	end

	# Match the `query` string against all indexed documents
	#
	# See `match_vector`.
	fun match_string(query: String): Array[IndexMatch[DOC]] do
		var vector = parse_string(query)
		var doc = new Document("", "", vector)
		return match_vector(doc.terms_frequency)
	end

	# Parse the `string` as a Vector
	#
	# Returns a vector containing the terms of `string`.
	fun parse_string(string: String): Vector do
		var reader = new StringReader(string)
		var vector = new Vector
		loop
			var token = reader.read_word
			if token == "" then break
			vector.inc(token)
		end
		return vector
	end
end