Appendix A: Keywords

The following words are reserved by the Kāra language. You cannot use them as identifiers.

Declaration keywords

Keyword	Purpose
`fn`	Declare a function
`struct`	Declare a struct
`enum`	Declare an enum
`trait`	Declare a trait
`impl`	Implement a trait or add methods to a type
`type`	Declare a type alias
`distinct`	Declare a distinct (newtype) alias
`const`	Declare a compile-time constant
`mod`	Declare a module
`use`	Bring a name into scope
`import`	Import an external package
`extern`	Declare a foreign function or type
`shared`	Mark a struct or enum as reference-semantics (RC)
`layout`	Declare a physical memory layout for a struct
`group`	Group fields within a layout block
`effect`	Declare an effect system definition
`resource`	Declare an effect resource
`verb`	Declare an effect verb
`alias`	Declare that two resource names refer to the same underlying resource

Keyword	Purpose
`pub`	Public — visible to external consumers
`private`	Private — visible only within the current directory

(Default visibility — no keyword — is project-internal: visible to all files in the project.)

Keyword	Purpose
`if`	Conditional branch
`else`	Fallthrough branch for `if`
`match`	Pattern-matching switch
`while`	Condition-driven loop
`for`	Iterator-driven loop
`in`	Separator between pattern and iterable in `for`
`loop`	Infinite loop
`return`	Early return from a function
`break`	Exit from a loop
`continue`	Skip to the next loop iteration
`defer`	Run a block when the enclosing scope exits (success path)
`errdefer`	Run a block when the enclosing scope exits via `?`-propagated error
`asm`	Inline assembly block
`global_asm`	Module-level assembly block

Keyword	Purpose
`let`	Declare a local binding
`mut`	Mark a binding or parameter as mutable

Keyword	Purpose
`own`	Explicit owned parameter mode (rarely needed — owned is the default)
`ref`	Borrow a value (read-only reference)
`weak`	Weak reference into an RC type
`lock`	Lock resource

Keyword	Purpose
`reads`	Effect: reads from a resource
`writes`	Effect: writes to a resource
`sends`	Effect: sends to a resource
`receives`	Effect: receives from a resource
`allocates`	Effect: allocates from a resource
`panics`	Effect: may panic
`blocks`	Effect: may block the calling thread
`suspends`	Effect: may yield to the scheduler
`with`	Introduce an effect annotation or effect variable
`transparent`	Mark an effect as transparent (not attributed to callers)
`stable`	Mark an effect annotation as part of the public API contract
`seq`	Sequential block
`par`	Parallel block (branches may execute concurrently)
`yield`	Yield a value from a generator

Keyword	Purpose
`as`	Type cast or trait disambiguation
`where`	Introduce generic bounds or refinement-type predicates
`dyn`	Dynamic dispatch through a trait object
`Self`	The type of the current `impl` block or trait
`self`	The receiver value within a method

Keyword	Purpose
`requires`	Precondition contract on a function
`ensures`	Postcondition contract on a function
`invariant`	Invariant check at the end of every method in an `impl` block

Keyword	Purpose
`unsafe`	Mark a block or function as bypassing safety checks

Keyword	Purpose
`providers`	Introduce a provider scope
`independent`	Declare that two resources are independent for conflict analysis

Keyword	Purpose
`true`	Boolean true
`false`	Boolean false

These words are reserved now; using them as identifiers is a compile error.

Keyword	Planned use
`f16`	Half-precision float (Phase 7+)
`bf16`	Brain-float (Phase 7+)

These are lexer-level keywords, not identifiers. They are always in scope and require no import.

i8, i16, i32, i64, u8, u16, u32, u64, f32, f64, bool, char, ! (the never type)