Enum Value 

#[repr(C)]
pub enum Value {
    Int(i64),
    Float(f64),
    Bool(bool),
    String(SeqString),
    Symbol(SeqString),
    Variant(Arc<VariantData>),
    Map(Box<HashMap<MapKey, Value>>),
    Quotation {
        wrapper: usize,
        impl_: usize,
    },
    Closure {
        fn_ptr: usize,
        env: Arc<[Value]>,
    },
    Channel(Arc<ChannelData>),
    WeaveCtx {
        yield_chan: Arc<WeaveChannelData>,
        resume_chan: Arc<WeaveChannelData>,
    },
}

Value: What the language talks about

This is pure data with no pointers to other values. Values can be pushed on the stack, stored in variants, etc. The key insight: Value is independent of Stack structure.

Memory Layout

Using #[repr(C)] ensures a predictable C-compatible layout:

• Discriminant (tag) at offset 0
• Payload data follows at a fixed offset

This allows compiled code to write Values directly without FFI calls, enabling inline integer/boolean operations for better performance.

Variants

Int(i64)

Integer value

Float(f64)

Floating-point value (IEEE 754 double precision)

Bool(bool)

Boolean value

String(SeqString)

String (arena or globally allocated via SeqString)

Symbol(SeqString)

Symbol (identifier for dynamic variant construction) Like Ruby/Clojure symbols - lightweight identifiers used for tags. Note: Currently NOT interned (each symbol allocates). Interning may be added in the future for O(1) equality comparison.

Variant(Arc<VariantData>)

Variant (sum type with tagged fields) Uses Arc for O(1) cloning - essential for recursive data structures

Map(Box<HashMap<MapKey, Value>>)

Map (key-value dictionary with O(1) lookup) Keys must be hashable types (Int, String, Bool)

Quotation

Quotation (stateless function with two entry points for calling convention compatibility)

• wrapper: C-convention entry point for calls from the runtime
• impl_: tailcc entry point for tail calls from compiled code (enables TCO)

Fields

wrapper: usize

C-convention wrapper function pointer (for runtime calls via patch_seq_call)

impl_: usize

tailcc implementation function pointer (for musttail from compiled code)

Closure

Closure (quotation with captured environment) Contains function pointer and Arc-shared array of captured values. Arc enables TCO: no cleanup needed after tail call, ref-count handles it.

Fields

fn_ptr: usize

Function pointer (transmuted to function taking Stack + environment)

env: Arc<[Value]>

Captured values from creation site (Arc for TCO support) Ordered top-down: env[0] is top of stack at creation

Channel(Arc<ChannelData>)

Channel (MPMC sender/receiver pair for CSP-style concurrency) Uses Arc for O(1) cloning - duplicating a channel shares the underlying handles. Send/receive operations use the handles directly with zero mutex overhead.

WeaveCtx

Weave context (generator/coroutine communication channels) Contains both yield and resume channels for bidirectional communication. Travels on the stack - no global registry needed. Uses WeaveChannelData with WeaveMessage for type-safe control flow.

Fields

yield_chan: Arc<WeaveChannelData>

resume_chan: Arc<WeaveChannelData>

Trait Implementations

impl Clone for Value

fn clone(&self) -> Value

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for Value

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Display for Value

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl PartialEq for Value

fn eq(&self, other: &Value) -> bool

Tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl Send for Value

impl StructuralPartialEq for Value

impl Sync for Value