Struct ScopedExpr 

pub struct ScopedExpr { /* private fields */ }

Shape 2 — a polydat expression bound to a parent kernel’s lexical scope. Compiled into a sub-context whose named output is the expression, evaluable many times against injected inputs. The return is whatever Wire type the bound stub was qualified with (ExprStub::returning::<T>), or its natural truthiness (is_true). A general-purpose, scope-bound, callable expression holder.

Implementations

impl ScopedExpr

pub fn bind( parent: &dyn Kernel, output: impl Into<String>, matter: GraphMatter, ) -> Result<Self, String>

Bind matter — which must define the named output (plus any extern wires it reads) — into a sub-context of parent, on parent’s engine. The expression is compiled once; call it repeatedly via eval / is_true after set-ing its inputs.

pub fn set(&mut self, name: &str, value: Value) -> Result<&mut Self, WriteError>

Set a runtime input wire by name before evaluating, converted to the wire’s type by the one conversion rule (crate::convert::to_port).

Refused with the error Kernel::set_input gives: WriteError::UnknownWire for a name the expression has no input for, WriteError::CoordinateSlot for a coordinate, WriteError::TypeMismatch for a value that does not convert to the wire’s type, and WriteError::ConstSlot for a const.

pub fn kernel(&mut self) -> &mut dyn Kernel

The bound sub-context, for callers that write a batch of inputs into it (e.g. a runtime-state snapshot) before evaluating.

pub fn eval(&mut self) -> Value

Evaluate (pull) the bound expression’s output.

pub fn is_true(&mut self) -> bool

Evaluate as a boolean — the default truthiness sense. Polydat comparisons / && / || yield U64 0/1 (not Bool), so truthiness is “non-zero”.