Enum Expr 

pub enum Expr {
    Const(Number),
    Var(usize),
    Binary(BinOp, Box<Expr>, Box<Expr>),
    Unary(UnaryOp, Box<Expr>),
    Sum(Vec<Expr>),
    Cse(Rc<Expr>),
}

Variants

Const(Number)

Numeric constant.

Var(usize)

Variable reference (0-based index into x).

Binary(BinOp, Box<Expr>, Box<Expr>)

Binary op: args = [lhs, rhs].

Unary(UnaryOp, Box<Expr>)

Unary op.

Sum(Vec<Expr>)

n-ary sum (opcode o54 — variadic; we may emit it from o0 folding optimization, but the parser treats o0 as binary).

Cse(Rc<Expr>)

Reference to a common subexpression (.nl V segment). The payload is a shared body; many references to the same CSE share one Rc, so the parsed problem is a DAG. Walking through Cse is mathematically equivalent to inlining the body at each occurrence (every reference is an independent occurrence in the chain rule), so eval/grad/collect_vars just recurse into the inner Expr.

Trait Implementations

impl Clone for Expr

fn clone(&self) -> Expr

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for Expr

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

Formats the value using the given formatter.