extends PrimValue
add dict and list
update
add test
support list[idx] and dict[key]
support a = {k:v, ...}
support b = [1, 2, 3, "xxx"]
index: int/str/float eg:a[index]
support +a, +3, -2, -a eg: -3 to 0 - 3 ...
list add append method
calc float op int
fix bug: readFile return ""
add toString
builtin Zero
add void null
add keyword： null type:null
add stmt end
update test
Update README.md
Update README.md
Update README.md
Update README.md