Variables & Values

Lumen is dynamically typed. A variable comes into existence the first time you assign to it — there’s no separate declaration syntax.

number = 42
result = number + 10

println result

Value types

Under the hood, every value carried on the stack or stored in a variable is tagged with one of three types:

You never annotate the type yourself — it’s inferred from the literal or the result of an expression, and it can change across the lifetime of a variable, since Lumen re-tags the value on every assignment.

x = 5        # integer
x = 'five'   # now a string — perfectly legal

Assignment

Assignment is a single =. The right-hand side can be a literal, another variable, or an arithmetic expression:

a = 10
b = a * 2
c = a + b - 1

Negative numbers work as you’d expect:

z = -20