Type Annotations

lil supports gradual type annotations using the typed keyword. Variables can be annotated with a type, and the runtime will automatically coerce values or error on incompatible types.

Variable Annotations

typed int x = 42
typed str name = "hello"
typed float pi = 3.14
typed bool flag = 1

Automatic Coercion

The runtime converts values when possible:

typed int x = "100"    : x is 100 (number)
typed str y = 99       : y is "99" (string)
typed float z = "3.14" : z is 3.14

Type Errors

Incompatible conversions fail at runtime:

try {
    typed int x = "hello"
} catch e {
    write("error: ", e.msg)
}

Output: error: cannot convert 'hello' to number

Function Annotations

Functions can annotate parameter types and return type:

#add(a typed int, b typed int) typed int {
    a + b
}

The runtime checks parameter types at call time and coerces the return value:

typed str s = "42"
typed int n = add(s, 1)  : n is 43

Why typed instead of x: int?

lil uses : for single-line comments (: this is a comment). Using x: int syntax would conflict. The typed keyword follows the same pattern as force/unforce:

• force x - mark variable as immutable
• typed int x - mark variable as typed

Standalone Conversion

The intify, stringify, and toggle forms still work for in-place conversion without annotations:

x = "hello"
intify x
: x is now 0 (conversion failed, defaults to 0)

y = 99
stringify y
: y is now "99"