ECHO: undef
ECHO: "string"
ECHO: "stringvar"
ECHO: a = 1, b = 2, true, c = false
ECHO: [1, "vecstr", 2.34, false]
ECHO: [1 : 2 : 10]
ECHO: vec = [1, 2, 3]
ECHO: range = [0 : 1 : 2]
ECHO: "string generated by str()"
ECHO: 0.8
ECHO: u = 2, v = 46
