Left Recursion or Left Associative Recursion

[decipher3114]

Winnow misses the support for recursion. The problem of left recursion causes the stack to overflow.

enum Expr {
    Reference(Reference),
    Index(Index)
    // Other types
}

// Current Implementation
struct Index {
    reference: Reference,
    indexes: Vec<Expr> // index brackets can have any expression inside
}

// Expected implementation
struct Index {
    expr: Box<Expression>,
    index: Box<Expression>
}

For instance take the case of $x[0][1][3], $x is reference followed by indexing values.
Instead of Ref (x); Vec ( [0], [1], [3] ), it should be

Expr( 
    Expr( 
        Expr(Ref(x));
        Index(0)
    );
    Index(1)
);
Index(3)

Current implementation restricts this behaviour because it involves Left Recursion.

Expr::parse internally calls the parse function for all the types.
If Expr::parse is used as the first parser inside Index::parse, it recurses indefinitely (for invalid cases).

I check #131 but I'm not sure if that is going to help here. there is no separator whatsoever.
I also thought about using the separated_foldl but the same thing.

Any guidance on how to handle this would be helpful.

[epage]

If you were looking at separated_foldl but not having a separator, then have you considered repeat().fold?

As for #131, there is no need for separators. If you look at the examples in #804, you'll see a full C expression parser which includes indexing.

[decipher3114]

Ahh, I see. I can use Postfix for indexing. Well, when can I expect the PR to be merged?

[epage]

The contributors are wrapping up some documentation