Struct Scope 

pub struct Scope { /* private fields */ }

Name bindings available while evaluating expressions: a file’s evaluated lets, later composed with a beam’s own parameter values.

Cloning is a plain HashMap clone. A Beamfile binds a handful of lets and a beam takes a handful of parameters, so this stays cheap in practice; a persistent/structural-sharing map would be premature machinery for that size.

Implementations

impl Scope

pub fn empty() -> Self

An empty scope: no lets, no parameters.

pub fn get(&self, name: &str) -> Option<&Value>

pub fn names(&self) -> impl Iterator<Item = &str>

The names currently bound in this scope, for “did you mean…?” suggestions on an unknown-variable error.

pub fn with_params(&self, params: &[String], args: &[String]) -> Self

Returns a new scope with params[i] bound to args[i] for each i, layered on top of self’s existing bindings (a parameter name that collides with a let shadows it for the new scope). This is the cheap, obvious composition the engine uses to bind a beam’s positional arguments before rendering its run/env templates: beam.scope.with_params(&beam.params, &args).

Mismatched lengths are not validated here: zip simply stops at the shorter of the two, so a missing argument leaves its parameter name unbound (rendering later fails with a plain “unknown variable” error, not an arity message) and an extra argument is silently ignored. The engine checks args.len() == beam.params.len() itself before calling this, so a real argument-count mismatch gets a clear diagnostic instead of surfacing here as a confusing unknown-variable one.

Trait Implementations

impl Clone for Scope

fn clone(&self) -> Self

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for Scope

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

Formats the value using the given formatter.

impl Default for Scope

fn default() -> Self

Returns the “default value” for a type.

impl PartialEq for Scope

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

Equality operator ==.

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

Inequality operator !=.

impl StructuralPartialEq for Scope