# language features

## IMPLEMENTED

### source and declarations

- newline-terminated statements and `#` comments
- immutable `::` bindings, mutable function-local `=` bindings, and `_` sinks
- immutable and mutable locals
- package-level globals and functions
- interned identifiers

### types and expressions

- exact-width `i8` through `i64`, `u8` through `u64`, `f32`, `f64`, `isize`, `usize`, `void`, and inferred integer-constrained `int`
- target-dependent atomic C primitives from `c_char` through `c_longdouble`
- C primitives remain semantically distinct from exact-width Brolang primitives until target lowering
- contextual integer literals and constant folding of addition and negation trees
- strict numeric conversions, checked integer addition, and unary negation
- arrays `[N]T`, sentinel arrays `[N;S]T`, single-item pointers `@T`, many-item pointers `*T`, sentinel many-item pointers `[*;S]T`, pointer offsets, slices, and explicit slicing
- immutable UTF-8 string literals typed as pointers to static sentinel arrays: `@[N;0]u8`
- pointer-to-array `.len`, indexing, and slicing without explicit dereference
- arrays expose `.len` but not `.ptr`; slices and pointers-to-arrays expose `.ptr` and preserve sentinel information when available
- information-preserving and information-forgetting pointer-to-array decay and sentinel slice/pointer weakening; array values never implicitly decay
- narrow immutable zero-terminated byte pointer conversion to `*c_char` and `[*;0]c_char`, without general `u8`/`c_char` interchange
- optionals with trapping postfix `?`, `orelse`, and nullable pointer representation
- source-order native structs, keyed literals, and defined or opaque pointer-only `c_struct`
- postfix pointer dereference, general writable locations, function calls, assignments, and returns

### functions and packages

- demand-monomorphized functions
- bodyful `c_func` definitions using the c calling convention
- bodyless `c_func` declarations with exact, globally unique external symbol names
- concrete-only foreign signatures
- Apple Silicon C ABI scalar and pointer lowering, including narrow integer extension attributes
- directory packages with merged declarations
- file-local relative imports, aliases, and qualified member access
- relative `.h` imports as synthetic package namespaces
- transitive external C function prototypes, typedef chains, C scalars, and pointers to opaque C records
- bodyless manual and imported C variadic declarations with target-aware default argument promotions
- reference-time diagnostics for unsupported imported C declarations

### compiler behavior

- error-tolerant compilation with runtime diagnostic traps
- lazy semantic checking of demanded function specializations
- demand-driven LLVM declarations for referenced foreign functions
- ordered linking of additional c sources, objects, and libraries
- replaceable dynamically loaded libclang C-import backend
- per-compilation C-header import caching by canonical path, target, ordered include paths, and ordered defines
- static, eager runtime, and deferred problematic globals

## PLANNED

### foreign functions and linking

- exporting brolang functions to c

### scalar and compound types

- tuples and native variadic functions
- C unions, C enums, and by-value C record ABI lowering

### advanced c imports

- C enums, external variables, function pointers, callbacks, macros, and static inline functions
- target-specific by-value C record and union ABI lowering