Crate elly 

Elly — a small language layered on Muon (see docs/elly-spec.md).

This crate implements the first, deliberately small subset: references, application, & abstraction, symbols, and positional lists with projection. It reads the syntax with the muon crate, parses that notation tree into an Expr, and evaluates it with a naive tree-walking evaluator.

let expr = elly::parse("(&x x) .foo").unwrap();
assert_eq!(elly::eval(&expr).unwrap().to_display(), ".foo");

Enums

Builtin

A native builtin operation in the reserved __ namespace. All are curried; see the integers section of docs/elly-spec.md.

EnvNode

One link of the environment list. A binding is a source name (patterns only ever bind names — Discard binds nothing, so there is no synthetic key).

Error

A failure at the syntax or parse stage.

Expr

An Elly expression in the first subset. Strings and records are deferred (see the spec), so there is no variant for them yet.

ParseError

A parse failure: the input is a valid Muon tree but not a well-formed Elly program in this subset.

Raised

A value unwinding through the single error channel (see the errors section of docs/elly-spec.md). Evaluation returns Result<Value, Raised>; a raise unwinds the ? chain up to the nearest boundary. Two kinds unwind together, differing only in what catches them:

Value

A runtime value.

Functions

eval

Evaluate an expression in the empty environment.

parse

Parse Elly source into an Expr: read the Muon syntax, then parse that notation tree into the AST.

parse_program

Parse a whole parsed program (one top-level chain) to an expression.

Type Aliases

Env

A shared, persistent environment.