Module evaltrees::cst

The concrete syntax tree.

Note that Decl and Expr both impl FromStr; hence they can be parsed with a simple .parse() call:

let expr: Expr = "(1 + 2) :: 3 :: []".parse().unwrap();
assert_eq!(expr, Expr::Op(Op::Cons,
    Box::new(Expr::Op(Op::Add,
        Box::new(Expr::Literal(Literal::Int(1))),
        Box::new(Expr::Literal(Literal::Int(2))),
    )),
    Box::new(Expr::Op(Op::Cons,
        Box::new(Expr::Literal(Literal::Int(3))),
        Box::new(Expr::Literal(Literal::Nil)),
    )),
));

let decl: Decl = "id x = x".parse().unwrap();
assert_eq!(decl, Decl {
    name: "id".into(),
    args: vec![
        Pattern::Binding("x".into(), ()),
    ],
    body: Expr::Variable("x".into()),
});

Structs

Decl	A function or value declaration.

Enums

Expr	An expression.

Functions

parse_decls

Parses multiple semicolon-terminated decls.