test_index = ->
	run_test [

		"A=((A11,A12),(A21,A22))",
		"",

		"A[1,1]",
		"A11",

		"A[1,2]",
		"A12",

		"A[2,1]",
		"A21",

		"A[2,2]",
		"A22",

		"A[1]",
		"(A11,A12)",

		"A[2]",
		"(A21,A22)",

		"A[1]=(B11,B12)",
		"",

		"A",
		"((B11,B12),(A21,A22))",

		"A[2]=(B21,B22)",
		"",

		"A",
		"((B11,B12),(B21,B22))",

		"A=((0,0),(0,0))",
		"",

		"A[1,1]",
		"0",

		# index of scalar ok

		"1[2]",
		"1",
	]