Chapters — 6. Keywords

06 — Keywords

Every reserved word in Cajeta. The authoritative list is the lexer, antlr4/CajetaLexer.g4; this table matches it exactly. A reserved word cannot name a variable, method, or type, except where a note says it is contextual.

Two familiar words are missing on purpose:

There is no new. Construction names a storage class instead — heap Circle(2.0) or stack Circle(2.0). See chapter 10.
true, false, and null are literals, not keywords.

Primitive type names

Keywords
`boolean`	truth value
`char`	32-bit Unicode codepoint
`int8` `int16` `int32` `int64` `int128`	signed integers
`uint8` `uint16` `uint32` `uint64` `uint128`	unsigned integers
`float16` `float32` `float64` `float128`	IEEE-754 binary floats
`float4e2m1` `float6e2m3` `float6e3m2` `float8e4m3` `float8e5m2` `float8e4m3fnuz` `float8e5m2fnuz`	OCP microscaling floats, storage-only

Chapter 08 covers all of these. bfloat16 and pointer are also native types, but they are type names resolved like any other, not reserved words.

Declarations

Keywords
`class` `interface` `enum` `record` `annotation` `view`	type kinds (chapter 09)
`package` `import`	namespacing
`extends` `implements`	inheritance
`sealed` `non-sealed` `permits`	sealed hierarchies
`void`	no return value
`var`	reserved for local type inference; parses but does not resolve yet
`mut`	contextual: record field mutation opt-in (chapter 09); an ordinary identifier everywhere else
`structure`	reserved; no declaration syntax yet — using it is a parse error

Control flow

Keywords
`if` `else`	branching
`switch` `case` `default` `yield`	selection and switch expressions
`for` `do` `while` `break` `continue`	loops
`return`	method exit
`try` `catch` `finally` `throw` `throws`	error handling
`assert`	assertions
`goto`	reserved, unused — no grammar rule accepts it

Objects and expressions

Keywords
`this` `super`	receiver and parent
`instanceof`	runtime type test
`operator`	operator-overload declarations

Memory and ownership

Keywords
`heap`	heap construction: `heap Foo(...)`
`stack`	stack construction: `stack Foo(...)`
`shared`	contextual: workgroup-shared placement inside `@Kernel` bodies only; an ordinary identifier everywhere else

Structured concurrency

Keywords
`async`	method modifier
`await` `spawn` `detach`	task expressions
`scope`	block that joins all child tasks before exiting. Also accepted as an annotation attribute name, as in `@Component(scope = "Request")`

Modules (reserved)

pModule open requires exports opens to uses provides with transitive — reserved by the lexer for a future module system. The parser accepts every one of them as an ordinary identifier today, so methods named open or requires keep parsing. Note the placeholder spelling pModule.

Modifiers

Keywords
`public` `protected` `private`	visibility
`static`	type-level member
`final`	no override / no reassignment
`abstract`	a method with no body that descendants must implement, or a class that cannot be allocated
`native`	implemented by the runtime
`const`	reserved; the grammar accepts it as a modifier
`strictfp` `transient` `volatile`	grammar-level modifiers, Java-familiar

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Source: docs/guide/06-keywords.md · 3 min · 572 words