Enum Expr 

pub enum Expr {
    Lit(ExprLit),
    Ref(String),
    Unary(UnOp, Box<Expr>),
    Binary(BinOp, Box<Expr>, Box<Expr>),
    Call(Builtin, Vec<Expr>),
    Field(Box<Expr>, String),
    Index(Box<Expr>, Box<Expr>),
}

A pure, total expression in AXON’s closed-catalog expression sublanguage (§Fase 70). Evaluates to a value with no side effects, no I/O, no recursion and no unbounded loops — so it is decidable and const-foldable. Mounted as the condition of an if (and, in later sub-fases, let values + where: predicates). Field/index access and the builtin catalog land in §70.c/d.

Variants

Lit(ExprLit)

A typed literal (42, 3.14, true, "hello").

Ref(String)

A reference to a binding or dotted path (x, User.tier).

Unary(UnOp, Box<Expr>)

A unary operation (-x, not x).

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

A binary operation (a + b, a >= b, a and b).

Call(Builtin, Vec<Expr>)

§Fase 70.c — a closed-catalog builtin call. args[0] is the receiver (the value before the .); any further entries are the call arguments. E.g. recent.length → Call(Length, [Ref("recent")]), name.starts_with("Dr") → Call(StartsWith, [Ref("name"), Lit(Str)]).

Field(Box<Expr>, String)

§Fase 70.d — field access on a non-reference base (items[0].name, (expr).field). A plain dotted path stays a Ref (a.b.c) for back-compat; this node is the structured form the JSONB SQL lowering (deferred §73) consumes. The String is the field name.

Index(Box<Expr>, Box<Expr>)

§Fase 70.d — index access base[index] (array element / string char).

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<(), Error>

Formats the value using the given formatter.