Standard Library · expr

class Node

The base class of every node in the reification tree.

since 0.1.0-alpha.1linuxwindowswasm

Overview

Node carries no data of its own. A walker holds nodes as Node and uses match to find out which concrete kind it has.

Examples

Telling node kinds apart

string kind(expr::Node n) {
    match (n) {
        expr::Field => { return "field"; }
        expr::Lit   => { return "literal"; }
        else        => { return "other"; }
    }
}
console.writeln(kind(expr::Field(["age"])));
console.writeln(kind(expr::Lit(3)));
console.writeln(kind(expr::Node()));

field
literal
other

See also

• Expr — A lambda together with a walkable description of its body.