Operators

Notes:

• + on two numbers adds them; if either side is a string or ton.html, it concatenates (converting the other side to text first) — the result is ton.html if either operand was.
• <, <=, >, >= compare two numbers numerically, or two strings/ton.html values lexicographically; comparing any other combination (or an array, a dict, a bool) is a runtime error rather than a silently meaningless result.
• ==/!= use structural equality: numbers/bools/nil compare by value, a string and an html value with the same text are equal, and arrays/dicts compare element-by-element (recursively) rather than by reference — [1, 2] == [1, 2] is true.
• / and % both raise "Division by zero" for a zero right-hand side, rather than producing inf/NaN silently.
• and/or are exact synonyms for &&/|| — use whichever reads better.
• ?? ("nil-coalescing") evaluates its left side and returns it as-is unless it's nil, in which case it evaluates and returns the right side instead — the right side is never evaluated otherwise, so it's safe to put a fallback that has side effects. Handy with dict lookups: dict["missing"] ?? "default".
• in tests membership: value in array checks the array's elements (using the same equality rules as ==), value in dict checks the dict's keys, and value in string checks for a substring. The right-hand side must be an array, dict, or string/ton.html — anything else is a runtime error.
• &, |, ^, ~, <<, >> treat both sides as integers (truncating any fractional part), operate on a 64-bit two's-complement representation, then convert the result back to TON618's usual number type — there's no separate integer type, so 6 & 3 is just a number like any other (2). Both operands must be numbers; anything else is a runtime error. &/|/^ all share one precedence level (looser than ==, tighter than &&) — use parentheses when mixing them for clarity.

Added in beta-2.0.0:

• -2 ** 2 is -4: ** binds tighter than the unary minus, as in maths and Python.
• + also concatenates two arrays ([1, 2] + [3] is [1, 2, 3], a new array); * repeats a string ("ab" * 3 is "ababab").
• a..b evaluates to an array of the integers from a up to b - 1 (a..=b includes b); in a for loop it counts lazily, so for i in 0..1000000 never builds an array.
• ?. works on property access, indexing and calls: obj?.name, list?.[0], callback?.(). Use it at each step that may be nil.

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