Enum Value 

pub enum Value {
    Nil,
    Bool(bool),
    Integer(i64),
    Real(f64),
    Char(char),
    String(Gc<String>),
    Symbol(Rc<str>),
    Keyword(Rc<str>),
    Pair(Gc<GcCell<PairData>>),
    Vector(Gc<GcCell<Vec<Value>>>),
    Procedure(Gc<Procedure>),
    Node(Rc<Box<dyn Node>>),
    NodeList(Rc<Box<dyn NodeList>>),
    Sosofo,
    Unspecified,
    Error,
}

A Scheme value

Corresponds to OpenJade’s ELObj base class.

Memory management: Uses Gc<T> for heap-allocated values. The gc crate provides conservative garbage collection similar to OpenJade’s Collector.

Note: We manually implement Trace/Finalize because Node and NodeList variants use Rc (not Gc) and contain trait objects.

Variants

Nil

The empty list ()

OpenJade: NilObj

Bool(bool)

Boolean: #t or #f

OpenJade: TrueObj / FalseObj

Integer(i64)

Exact integer

OpenJade: IntegerObj (long n_)

Real(f64)

Inexact real number

OpenJade: RealObj (double n_)

Char(char)

Unicode character

OpenJade: CharObj (Char ch_)

String(Gc<String>)

Immutable string

OpenJade: StringObj (extends StringC)

Using Gc<String> for garbage collection.

Symbol(Rc<str>)

Interned symbol

OpenJade: SymbolObj (StringObj* name_)

Symbols are interned (shared) for efficiency. Using Rc<str> since symbols are immutable and shared.

Keyword(Rc<str>)

Keyword (DSSSL extension)

OpenJade: KeywordObj

Keywords are like symbols but in a separate namespace.

Pair(Gc<GcCell<PairData>>)

Cons cell (pair)

OpenJade: PairObj (ELObj* car_, ELObj* cdr_)

Using Gc<PairData> for garbage-collected pairs. GcCell allows mutation (for set-car!/set-cdr!).

Vector(Gc<GcCell<Vec<Value>>>)

Vector (array)

OpenJade: VectorObj (Vector<ELObj*>)

Using Gc<GcCell<Vec<Value>>> for mutable vectors.

Procedure(Gc<Procedure>)

Procedure (function)

OpenJade: FunctionObj (various subclasses)

Can be:

• Built-in primitive (Rust function)
• User-defined lambda (compiled bytecode or AST)

Node(Rc<Box<dyn Node>>)

A node in the document grove

Represents a node from the XML document tree. Corresponds to OpenJade’s node objects in the grove.

Phase 3: Now fully implemented with libxml2 grove.

Uses Rc<Box<dyn Node>> instead of Gc because:

• Nodes are owned by the grove, not the Scheme GC
• Grove lifetime is managed separately
• Trait objects can’t derive Trace automatically

NOTE: Managed by Rc, not GC - see manual Trace impl below

NodeList(Rc<Box<dyn NodeList>>)

Node list (grove query result)

Represents a collection of nodes from grove queries. Corresponds to DSSSL node-list objects.

Phase 3: Now fully implemented with libxml2 grove.

Uses Rc<Box<dyn NodeList>> for same reasons as Node.

NOTE: Managed by Rc, not GC - see manual Trace impl below

Sosofo

Sosofo (flow object sequence)

Placeholder - will be properly implemented in Phase 4.

Unspecified

Unspecified value

Returned by expressions with unspecified results (like set!).

OpenJade: UnspecifiedObj

Error

Error marker

Used internally for error propagation.

OpenJade: ErrorObj

Implementations

impl Value

pub fn bool(b: bool) -> Self

Create a boolean value

pub fn integer(n: i64) -> Self

Create an integer value

pub fn real(n: f64) -> Self

Create a real value

pub fn char(ch: char) -> Self

Create a character value

pub fn string(s: String) -> Self

Create a string value

pub fn symbol(s: &str) -> Self

Create a symbol value

pub fn keyword(s: &str) -> Self

Create a keyword value

pub fn cons(car: Value, cdr: Value) -> Self

Create a cons cell (pair)

pub fn cons_with_pos(car: Value, cdr: Value, pos: Position) -> Self

Create a cons cell with source position

pub fn vector(elements: Vec<Value>) -> Self

Create a vector

pub fn primitive( name: &'static str, func: fn(&[Value]) -> Result<Value, String>, ) -> Self

Create a built-in primitive procedure

pub fn lambda(params: Vec<String>, body: Value, env: Gc<Environment>) -> Self

Create a user-defined lambda procedure

pub fn lambda_with_source( params: Vec<String>, body: Value, env: Gc<Environment>, source: Option<SourceInfo>, name: Option<String>, ) -> Self

Create a user-defined lambda procedure with source location

pub fn node(node: Box<dyn Node>) -> Self

Create a node value

pub fn node_list(node_list: Box<dyn NodeList>) -> Self

Create a node list value

impl Value

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

Scheme equal? - Deep structural equality

Corresponds to OpenJade’s ELObj::equal()

Recursively compares:

• Lists and vectors: Element-wise comparison
• Strings: Content comparison
• Numbers: Numeric equality
• Everything else: Same as eqv?

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

Scheme eqv? - Equivalence (same value, not necessarily same object)

Corresponds to OpenJade’s ELObj::eqv()

Returns true if:

• Both are the same boolean value
• Both are the same number (integer or real)
• Both are the same character
• Both are the same symbol (symbols are interned)
• Both are the same keyword
• Both refer to the same pair/vector/procedure object
• Both are nil

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

Scheme eq? - Object identity (same object in memory)

For most types, same as eqv?. Symbols and keywords are interned, so eq? and eqv? are equivalent for them.

impl Value

pub fn is_nil(&self) -> bool

Is this the nil value?

pub fn is_bool(&self) -> bool

Is this a boolean?

pub fn is_true(&self) -> bool

Is this true? (for conditionals)

In Scheme, only #f is false; everything else (including nil) is true.

pub fn is_integer(&self) -> bool

Is this an integer?

pub fn is_real(&self) -> bool

Is this a real number?

pub fn is_number(&self) -> bool

Is this a number (integer or real)?

pub fn is_char(&self) -> bool

Is this a character?

pub fn is_string(&self) -> bool

Is this a string?

pub fn is_symbol(&self) -> bool

Is this a symbol?

pub fn is_pair(&self) -> bool

Is this a pair?

pub fn is_list(&self) -> bool

Is this a list? (nil or pair)

pub fn is_vector(&self) -> bool

Is this a vector?

pub fn is_procedure(&self) -> bool

Is this a procedure?

pub fn is_node(&self) -> bool

Is this a node?

pub fn is_node_list(&self) -> bool

Is this a node list?

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 Finalize for Value

Manual implementation of Finalize for Value

No finalization needed - all cleanup is handled by Drop impls

fn finalize(&self)

impl Trace for Value

Manual implementation of Trace for Value

We implement this manually because:

• Node and NodeList use Rc<Box>, which doesn’t implement Trace
• These are managed by Rc, not the GC
• All other variants use Gc and need proper tracing

unsafe fn trace(&self)

Marks all contained Gcs.

unsafe fn root(&self)

Increments the root-count of all contained Gcs.

unsafe fn unroot(&self)

Decrements the root-count of all contained Gcs.

fn finalize_glue(&self)

Runs Finalize::finalize() on this object and all contained subobjects