#[derive(AST)] for CST Enums

[atahanyorganci]

Current AST implementation in Alloy includes enums such as Expression that is discriminated union of BinaryExpression, UnaryExpression etc.

// src/ast/expression/mod.rs:21
pub enum Expression {
    Value(Value),
    Binary(BinaryExpression),
    Unary(UnaryExpression),
    Identifier(IdentifierExpression),
}

This AST enum has to be derived from CST one candidate CST that can be used to generate Expression AST is provided below.

#[derive(AST)]
pub enum ExpressionCST {
    Value(Spanned<Value>),
    Binary(BinaryExpressionCST),
    Unary(UnaryExpressionCST),
    Identifier(IdentifierExpressionCST),
}

Originally posted by @atahanyorganci in #24 (comment)