Wikipedia: Type systemtype_name returns any value's type as a string. is_error, is_undefined, and is_callable are dedicated predicates for the three types that need special handling.
fmt := import("fmt")fmt.println(type_name(42))
fmt.println(type_name(3.14))
fmt.println(type_name("hello"))
fmt.println(type_name(true))
fmt.println(type_name(bytes("x")))
fmt.println(type_name([1, 2]))
fmt.println(type_name({a: 1}))double := func(x) { return x * 2 }
fmt.println(type_name(double))
fmt.println(is_callable(double))
fmt.println(is_callable(42))fmt.println(is_error(error("oops")))
fmt.println(is_undefined(func() {}()))describe := func(v) {
t := type_name(v)
if t == "int" || t == "float" {
return fmt.sprintf("number: %v", v)
} else if t == "string" {
return "string: " + v
} else if t == "array" {
return fmt.sprintf("array of %d", len(v))
}
return "other: " + t
}
fmt.println(describe(42))
fmt.println(describe("hi"))
fmt.println(describe([1, 2, 3]))
fmt.println(describe(true))try it
int float string bool bytes array map compiled-function true false true true number: 42 string: hi array of 3 other: bool