# Appendix A: Keywords and operators > Appendix A: every Alice keyword, modifier and operator, with a one-line meaning and the chapter that explains it. Canonical: https://alice-lang.org/documentation/learn/keywords/ [Documentation index](https://alice-lang.org/documentation/llms.txt) ยท [Complete book](https://alice-lang.org/llms-full.txt) This appendix lists the words and symbols with a fixed meaning in Alice. The [syntax reference](https://alice-lang.org/documentation/reference/syntax.md) has the full grammar. ## Keywords | Keyword | Meaning | Chapter | | ---------------------------------------------------------- | ------------------------------------------------------------- | ---------------------------------------------------------------------------------------------------------------------------------- | | `def` ... `end` | define a method; `def name = expr` is the one-line form | [3](https://alice-lang.org/documentation/learn/common-concepts.md) | | `return`, `yield` | leave a method with a value; call the method's block | [3](https://alice-lang.org/documentation/learn/common-concepts.md), [4](https://alice-lang.org/documentation/learn/collections.md) | | `if`, `elsif`, `else`, `unless` | choose a branch; `unless` is "if not"; postfix forms `x if c` | [3](https://alice-lang.org/documentation/learn/common-concepts.md) | | `case`, `when`, `in`, `then` | compare with `when`, match patterns with `in` | [3](https://alice-lang.org/documentation/learn/common-concepts.md), [7](https://alice-lang.org/documentation/learn/sum-types.md) | | `while`, `until`, `for` ... `in`, `loop`, `do` | loops; `do ... end` is a block | [3](https://alice-lang.org/documentation/learn/common-concepts.md) | | `break`, `next` | leave a loop; skip to its next round | [2](https://alice-lang.org/documentation/learn/guessing-game.md) | | `begin`, `rescue`, `else`, `ensure`, `raise`, `retry` | exceptions | [8](https://alice-lang.org/documentation/learn/errors.md) | | `val` | a binding that cannot be reassigned | [3](https://alice-lang.org/documentation/learn/common-concepts.md) | | `nil`, `true`, `false`, `self`, `super` | literal values, the current object, the parent's method | [3](https://alice-lang.org/documentation/learn/common-concepts.md), [6](https://alice-lang.org/documentation/learn/types.md) | | `class`, `struct`, `record`, `enum`, `module`, `interface` | define types and modules | [6](https://alice-lang.org/documentation/learn/types.md), [7](https://alice-lang.org/documentation/learn/sum-types.md) | | `abstract`, `private`, `protected`, `public` | abstract members; visibility | [6](https://alice-lang.org/documentation/learn/types.md) | | `getter`, `setter`, `property` | field accessors | [6](https://alice-lang.org/documentation/learn/types.md) | | `include`, `extend`, `using`, `require`, `namespace` | mixins; imports; loading files; .NET namespaces | [6](https://alice-lang.org/documentation/learn/types.md), [14](https://alice-lang.org/documentation/learn/dotnet.md) | | `own`, `borrow`, `scope` | ownership contracts and lifetime regions | [9](https://alice-lang.org/documentation/learn/ownership.md) | | `pure`, `safe`, `inline` | method modifiers: no effects; no ambient authority; inline | [10](https://alice-lang.org/documentation/learn/safety.md), [12](https://alice-lang.org/documentation/learn/performance.md) | | `par`, `par for` | fork two pure calls; require a parallel loop | [11](https://alice-lang.org/documentation/learn/parallelism.md) | | `spawn`, `async`, `await`, `for await` | threads and asynchronous code | [15](https://alice-lang.org/documentation/learn/async.md) | | `gpu for`, `gpu` ... `end` | GPU loops and device regions | [16](https://alice-lang.org/documentation/learn/gpu.md) | | `lib`, `fun`, `unsafe` | C libraries and raw pointers | [17](https://alice-lang.org/documentation/learn/native.md) | | `unchecked` ... `end` | integer arithmetic that wraps | [3](https://alice-lang.org/documentation/learn/common-concepts.md) | | `rule` | a provable property | [13](https://alice-lang.org/documentation/learn/proofs.md) | | `it`, `_1` ... `_9` | implicit block parameters | [4](https://alice-lang.org/documentation/learn/collections.md) | ## Operators | Operator | Meaning | | ------------------------- | ---------------------------------------------------------------- | | `+ - * / % **` | arithmetic; integer `/` and `%` round down; overflow raises | | `&+ &- &*` | wrapping integer arithmetic | | `== != < <= > >=` | comparison | | `<=>` | three-way comparison: -1, 0 or 1 | | `&& \|\| !`, `and or not` | logic; `x \|\| default` also supplies a value for `nil` | | `= += -= *= /=` | assignment and compound assignment | | `c ? a : b` | conditional expression | | `..`, `...` | inclusive and exclusive ranges | | `<<` | append to a `List`, a `StringBuilder` or a `String.build` buffer | | `=~`, `!~` | regular-expression match position, and its negation | | `%` on a string | format: `"%05d" % [42]` | | `&:name` | a block that calls `name` on its argument | | `->(x : T) { ... }` | a lambda | | `::` | a constant or variant inside a type or module: `Light::Red` | | `@field`, `@@class_field` | instance and class fields | | `x?` in a type | nilable: `String?` | | `@[Attribute]` | an attribute, Alice or .NET | Classes can define most operators as methods: `def +(other : T)`, `def <=>(other : T)`, `def [](i : Int32)`. See [chapter 6](https://alice-lang.org/documentation/learn/types.md). ## Attributes used in this book | Attribute | Effect | | ---------------------------- | ----------------------------------------------------------- | | `@[Stack]` | a struct that may only live on the stack | | `@[SoA]` | a record struct stored as columns in `SoA(T)` | | `@[Hot]` | optimize fully from the first call | | `@[Native]` | compile the method to C with clang | | `@[Link("lib")]`, `@[Fast]` | the shared library of a `lib`; a call without GC transition | | `@[JSExport]`, `@[JSImport]` | WebAssembly interop with JavaScript | | `@[Test]`, `@[Cases(...)]` | xUnit-style tests | ## Continue reading - Previous: [22. Alice for AI agents](https://alice-lang.org/documentation/learn/agents.md) - Next: [Appendix B: Error codes](https://alice-lang.org/documentation/learn/error-codes.md)