Parsing to dictionaries

[JaapWijnen]

Hi! I've been doing some xml related parsing recently and I run into an issue when parsing attributes such as:
<xmlTag "attr1"="value1" "attr2"="value2" />
When parsing these to a dictionary round tripping wil occasionally fail since dictionaries are unordered so the printed order will be reversed for example.
So I switched to swift-collections' OrderedDictionary which fixed the problem.
A few of swift-collections' types don't conform to collection however due to protocol requirement clashes with subscripts I believe.

Specifically the End() parser requires Input to conform to Collection. Summarising I have two questions:

• Are there better ways to get around my ordered dictionary problem with xml/html attributes?
• Could we loosen the restrictions on the End parser to Sequence?

Something like this seems to work in this case:

struct SequenceEnd<Input: Sequence>: Parser {
    func parse(_ input: inout Input) throws {
        var iterator = input.makeIterator()
        guard iterator.next() == nil else {
            throw SomeError()
        }
    }
}

Let me know what you think!