Appendix C — Operator precedence and associativity
Normative definition: §4.5. From tightest-binding (1) to loosest (8). Binary levels are left-associative; prefix levels are right-associative.
| Precedence | Operators | Kind | Associativity | |
|---|---|---|---|---|
| 1 | [] (index/slice) · . (field / tuple index) · or_return · ... | postfix | left | |
| 2 | - · & (address-of) · ~ | unary prefix | right | |
| 3 | * · / · % · << · >> · & (bitwise) | binary | left | |
| 4 | + · - · `\ | · ^` | binary | left |
| 5 | is | binary, non-associative | — | |
| 6 | == · != · < · > · <= · >= · in | binary | left | |
| 7 | not | unary prefix | right | |
| 8 | and | binary | left | |
| 9 | or | binary | left |
Notes:
- Go-style precedence: shifts (
<<,>>) and bitwise-AND (&) bind at the multiplicative level (3); bitwise-OR/XOR (|,^) bind at the additive level (4). Every bitwise operator therefore binds tighter than any comparison, soa & b == cparses as(a & b) == c. &is overloaded across levels: unary address-of /inoutargument (level 2) and binary bitwise-AND (level 3).- Assignment (
=), declare-and-infer (:=), and compound assignment are not expression operators — they are statement-level and never appear inside an expression (§4.3.1). - The grammar fixes associativity only; the order of side effects among operands and arguments is unspecified (§13.4, Appendix F).