Need more examples with anonymous sequences

[singalen]

Hi, I'm trying pest-ast for my project. So far, it's been super-helpful.

Now, I have a few cases for which I cannot find a type mapping. i have looked in issues, in the examples of pest-ast and the examples of derive.

A repetition of an anonymous sequence

comparison = { arith_expr ~ (comp_op ~ arith_expr)* }

In #8, I see an example:

struct assigns<'pest>(
  #[pest_ast(outer)] Span<'pest>,
  Vec<struct _1(assign<'pest>)>,
  assign<'pest>,
);

But Vec<struct _1(assign<'pest>)> is not a valid Rust, there are no anonymous structs.

I can try to extract a named struct, but there is no grammar rule to put into pest_ast, and pest_ast is required:

    #[derive(Debug, FromPest)]
    // FIXME: This probably shouldn't work!
    #[pest_ast(rule(Rule::comparison))]
    pub struct ComparisonPart2 {
        pub op: CompOr,
        pub expr: ArithExpr
    }

    #[derive(Debug, FromPest)]
    #[pest_ast(rule(Rule::comparison))]
    // comparison = { arith_expr ~ (comp_op ~ arith_expr)* }
    pub struct Comparison {
        pub expr: ArithExpr,
        pub continuation: Vec<ComparisonPart2>,
        // pub continuation: Vec<(CompOr, ArithExpr)>,
    }

I'm not sure it will work (I haven't finished a mapping for my grammar yet).

A nested choice

arith_expr = { term ~ ((plus|minus) ~ term)* } How do I map the (plus|minus) part? To an enum like this?

    #[derive(Debug, FromPest)]
    #[pest_ast(rule(Rule::plus))]
    pub struct Plus {
    }

    #[derive(Debug, FromPest)]
    #[pest_ast(rule(Rule::minus))]
    pub struct Minus {
    }

    #[derive(Debug, FromPest)]
    #[pest_ast(rule(Rule::arith_expr))]
    pub enum PlusMinus {
        Plus{ plus: Plus },
        Minus{ minus: Minus },
    }

    #[derive(Debug, FromPest)]
    #[pest_ast(rule(Rule::arith_expr))]
    pub struct ArithExprPart2 {
        pub op: PlusMinus,
        pub term: Term,
    }

    #[derive(Debug, FromPest)]
    #[pest_ast(rule(Rule::arith_expr))]
    // arith_expr = { term ~ ((plus|minus) ~ term)* }
    pub struct ArithExpr {
        pub term: Term,
        pub tail: Vec<ArithExprPart2>
    }

It would be great to have a such example. It would be a bit less great to know it's impossible as of now.

Thank you!