ZoKrates

Variables can have any name which does not start with a number. Variables are mutable, and always passed by value to functions.

Variables need to be declared to be used. Declaration and definition are always combined, so that undefined variables do not exist.

def main():
    // declare and define `my_variable`
    field my_variable = 2
    // redefine `my_variable`
    my_variable = 3
    return

Shadowing is not allowed.

def main() -> field:
    field a = 2
    // field a = 3 <- not allowed
    for u32 i in 0..5 do
        // field a = 7 <- not allowed
    endfor
    return a

Functions have their own scope

def foo() -> field:
    // return myGlobal <- not allowed
    return 42

def main() -> field:
    field myGlobal = 42
    return foo()

For-loops have their own scope

def main() -> u32:
    u32 a = 0
    for u32 i in 0..5 do
        a = a + i
    endfor
    // return i <- not allowed
    return a