Keywords

q64 reserves the following 54 keywords. This list is generated directly from the compiler’s lexer, so it never drifts from what the parser actually recognizes.

Keyword	Description	Token kind
actor	Declare an actor — an isolated unit of concurrent state with message handlers.	KW_ACTOR
as	Bind an import under a different name (import foo as bar).	KW_AS
break	Exit the innermost loop, optionally yielding a value.	KW_BREAK
catch	Handle an error or a failed task.	KW_CATCH
const	A compile-time constant binding.	KW_CONST
continue	Skip to the next iteration of the innermost loop.	KW_CONTINUE
draw	A screen’s declarative view block; its statements are widget calls.	KW_DRAW
dyn	Dynamic dispatch over a face used as a type (dyn Face).	KW_DYN
effect	Declare an effect or an effect relationship (spec/effects.md).	KW_EFFECT
else	The alternative branch of an if.	KW_ELSE
enum	Declare an enum (sum type) with named variants.	KW_ENUM
face	Declare a face — q64’s interface/trait for polymorphism (spec/faces.md).	KW_FACE
false	The boolean literal false.	KW_FALSE
fit	Implement a face for a type (fit T : Face).	KW_FIT
fn	Declare a function.	KW_FN
for	Iterate over a sequence (for x in xs).	KW_FOR
forall	Universal quantifier used in laws and generic reasoning.	KW_FORALL
from	Source clause of a re-export.	KW_FROM
graph	A stream graph — connected dataflow stages (spec/streams.md).	KW_GRAPH
handle	Declare an actor’s handler for a message.	KW_HANDLE
if	A conditional.	KW_IF
import	Bring a module or selected names into scope.	KW_IMPORT
in	The by-value in parameter mode; also the for x in xs separator.	KW_IN
law	State an algebraic law a fit must satisfy (property-checked).	KW_LAW
let	An immutable local binding.	KW_LET
loop	An unconditional loop (exit with break).	KW_LOOP
match	Pattern-match a value against arms.	KW_MATCH
move	The move parameter mode — transfer ownership.	KW_MOVE
on	An event handler in a screen (on press(…) { … }).	KW_ON
out	The out parameter mode — a write-only output parameter.	KW_OUT
panic	Abort the current computation with an error.	KW_PANIC
pub	Mark an item public — part of the qube’s exported surface.	KW_PUB
ref	A reference type (ref T) or the ref parameter mode.	KW_REF
region	A memory region — the unit of allocation lifetime (spec/memory.md).	KW_REGION
return	Return a value from a function.	KW_RETURN
scope	A structured-concurrency scope that bounds spawned tasks.	KW_SCOPE
screen	The QView frontend DSL: state, a draw block, and on handlers.	KW_SCREEN
select	Wait on multiple channel operations, taking the first ready.	KW_SELECT
self	The receiver value of a method.	KW_SELF
Self	The enclosing / implementing type.	KW_SELF_TYPE
spawn	Start a concurrent task within a scope.	KW_SPAWN
state	A reactive state binding (in a screen or actor).	KW_STATE
struct	Declare a struct (record type).	KW_STRUCT
tell	Send a fire-and-forget message to an actor.	KW_TELL
trap	Raise an unrecoverable trap.	KW_TRAP
true	The boolean literal true.	KW_TRUE
try	Propagate an error from a Result (early-return on failure).	KW_TRY
type	Declare a type alias (type Name = …).	KW_TYPE
use	Re-export names from a module (pub use …).	KW_USE
var	A mutable local binding.	KW_VAR
where	Attach bounds to generic parameters.	KW_WHERE
while	A loop that runs while a condition holds.	KW_WHILE
with_capabilities	Run a block with a narrowed capability set (grant / deny).	KW_WITH_CAPABILITIES
None	The Option None value / pattern.	KW_NONE