# Appends CSV records to a file.
#
# By default, uses the format recommended by RFC 4180 (see `rfc4180`).
#
# Note: If a record contains only an empty cell, its representation is
# undistinguishable from an empty line. This is because the empty values are
# always written unescaped in order to avoid them to be interpreted as escaped
# delimiters by some parsers.
#
# ~~~nit
# var out = new StringWriter
# var writer = new CsvWriter(out)
# writer.write_elements(1, 2.0, "foo\nbar")
# writer.write_line([""])
# assert out.to_s == """1,2.0,"foo\nbar"\n\n"""
# ~~~
class CsvWriter
	super CsvStream

	# The output stream.
	var ostream: Writer

	# Write several lines to a stream
	fun write_lines(lines: Array[Array[Object]]) do for i in lines do write_line i

	# Append the elements in `els` as a record.
	#
	# The representation of each cell is determined by `to_s`.
	fun write_elements(els: Object...) do
		var os = ostream
		var esc = delimiter
		var sep = separator
		var eol = eol
		for i in [0 .. els.length - 1[ do
			os.write(els[i].to_s.escape_to_csv(sep, esc, eol))
			os.write_char(sep)
		end
		os.write(els.last.to_s.escape_to_csv(sep, esc, eol))
		os.write(eol)
	end

	# Append the specified record.
	#
	# The representation of each cell is determined by `to_s`.
	fun write_line(line: Array[Object]) do
		var os = ostream
		var esc = delimiter
		var sep = separator
		var eol = eol
		for i in [0 .. line.length - 1[ do
			os.write(line[i].to_s.escape_to_csv(sep, esc, eol))
			os.write_char(sep)
		end
		os.write(line.last.to_s.escape_to_csv(sep, esc, eol))
		os.write(eol)
	end
end