Types & literals

Rain is dynamically typed. Values know their type at runtime; you don't declare types on variables.

Numbers are IEEE doubles. Whole numbers print without a trailing .0.

Strings are immutable double-quoted literals. See the Strings page for interpolation, escaping, concatenation, and the str module.

nil is the absence of a value. Only false and nil are falsy in conditions.

Arrays are first-class values created with #[ ... ]. Maps are string-keyed hash tables written { "key": value }. See the Maps page.

Use typeOf(value) to read a value's runtime type as a string, isType(value, name) to test it, and assertType(value, name) to enforce it (raises a runtime error on mismatch).

print 42;
print 3.14;
print "hello";
print true;
print false;
print nil;
print #[1, 2, 3];
print {"name": "Rain", "version": 1};

42
3.14
hello
true
false
nil
[1, 2, 3]
{"name":Rain, "version":1}

print typeOf(42);
print typeOf("hi");
print typeOf(nil);
print typeOf(#[1, 2]);

print isType(42, "number");
print isType(42, "string");

var n = assertType(42, "number");
print n;

number
string
nil
array
true
false
42