Variables & Types

RuneLang is a statically-annotated, dynamically-typed language. You declare the type when creating a variable, and the runtime enforces it.

Declaring variables

Every variable declaration follows the pattern:

Type name is value;

Variables are immutable by default. This is a deliberate design choice — immutability prevents an entire class of bugs.

Countstone max_hp is 100;
max_hp is written as 200;  // ERROR: cannot reassign immutable variable

To make a variable mutable, use the Mutable keyword:

Mutable Countstone current_hp is 100;
current_hp is written as current_hp - 25;  // works

The Enchanted keyword is an alias for declaring immutable variables explicitly:

Enchanted Countstone GRAVITY is 10;  // same as without Enchanted

Primitive types

Countstone (integer)

64-bit signed integers.

Countstone age is 25;
Countstone damage is -10;
Countstone hex_val is 0xFF;        // 255
Countstone bin_val is 0b1010;      // 10
Countstone big_num is 1_000_000;   // underscores for readability

Potion (float)

64-bit floating point numbers.

Potion pi is 3.14159;
Potion crit_chance is 0.25;
Potion temperature is -40.0;

Runestone (string)

UTF-8 strings with escape sequences.

Runestone name is "Gandalf the Grey";
Runestone quote is "He said \"you shall not pass!\"";
Runestone multiline is "line one\nline two";

Supported escape sequences: \n (newline), \t (tab), \r (carriage return), \\ (backslash), \" (quote), \0 (null byte).

Flagstone (boolean)

Two values: Truth and Falsehood.

Flagstone is_alive is Truth;
Flagstone game_over is Falsehood;

Void

The absence of a value. Returned by functions that don’t return anything.

Void nothing is Void;

Collection types

Scroll (array)

Ordered, indexable collections. See Scrolls & Tomes for full details.

Scroll heroes is ["Gandalf", "Frodo", "Aragorn"];
Scroll numbers is [1, 2, 3, 4, 5];
Scroll mixed is [42, "hello", Truth];

Tome (map)

Key-value dictionaries. Keys can be strings, integers, or booleans.

Tome stats is {"str": 18, "dex": 14, "con": 16};
Tome config is {"host": "localhost", "port": 8080};

Special types

Familiar

Used for Guild instances (objects). When a function takes an object, annotate it as Familiar:

Ritual heal(Familiar target, Countstone amount) begins
    target.health is written as target.health + amount;
end of Ritual

Coffer (byte)

A single byte value (0-255). Useful for binary data.

Coffer byte_val is 0xFF;

Hex

A type for raw hexadecimal data.

Assignment

RuneLang supports two assignment syntaxes:

// full form
x is written as x + 1;

// short form
x is x + 1;

Both are equivalent. The full form reads more naturally in verbose code; the short form is concise.

Type casting

Use Transmute to convert between types:

Runestone age_str is Transmute(25, "Runestone");     // "25"
Countstone num is Transmute("42", "Countstone");     // 42
Countstone truncated is Transmute(3.99, "Countstone"); // 3

Type checking

Use TypeOf to inspect a value’s type at runtime:

Chant(TypeOf(42));        // "Countstone"
Chant(TypeOf("hello"));   // "Runestone"
Chant(TypeOf(3.14));      // "Potion"
Chant(TypeOf(Truth));     // "Flagstone"
Chant(TypeOf([1, 2]));    // "Scroll"