Enum Expression

examples/parametrized_function.rs:70–97

#[derive(Clone, Debug)]
enum Expression {
    /// Conditional expression.
    /// Requirement: `cond` more concrete than bool, `cons` and `alt` compatible.
    /// Returns: meet of `cons` and `alt`.
    Conditional {
        cond: Box<Expression>,
        cons: Box<Expression>,
        alt: Box<Expression>,
    },
    /// Polymorphic function f<T_1: C_1, ..., T_n: C_n>(p_1: C_{n+1}, ..., p_m: C_{n+m}) -> T
    /// Arguments:
    ///     `name` for illustration,
    ///     `param_constraints`: vector of parameters and their constraints if any, in this example vec![C_1, ..., C_n].
    ///     `arg_types`: vector of type constraints on the arguments, in this example vec![C_{n+1}, ..., C_{n+m}]. May refer to parameters.
    ///     `args`: vector containing all argument expressions.
    ///     `returns`: return type. May refer to a parameter.
    /// Requirement: each argument needs to comply with its constraint. If several arguments refer to the same parametric type, they need to be compliant.
    /// Returns: `returns`.
    PolyFn {
        name: &'static str,
        param_constraints: Vec<Option<Variant>>,
        args: Vec<(ParamType, Expression)>,
        returns: ParamType,
    },
    ConstInt(i128),
    ConstBool(bool),
    ConstFixed(i64, u64),
}

impl Constructable for Variant {
    type Type = Type;