Type alias Expr

Expr: {
    kind: "expr.literal";
    unit?: Unit;
    value: number;
} | {
    id: ID;
    kind: "expr.param";
} | {
    kind: "expr.binary";
    left: Expr;
    op: "+" | "-" | "*" | "/";
    right: Expr;
} | {
    kind: "expr.neg";
    value: Expr;
}