Solr Configuration File Schema

I'm starting to like Solr. There's just one thing I can't stand. That's when there is no schema for editing configuration files.

This is what the Wiki page says:

:TODO: we should try to make a DTD for the schema

Now, no matter how much I like Solr and miss a schema: creating a DTD for it is just so 90s. There's gotta be something better. Why not a RelaxNG schema instead? This is my first stab at it:

datatypes d = "http://www.w3.org/2001/XMLSchema"

start =
  element schema {
    attribute name { text }?,
    attribute version { text },
    types,
    fields,
    element uniqueKey { text },
    element defaultSearchField { text },
    element solrQueryParser {
      attribute defaultOperator { "AND" | "OR" }
    },
    copyField*,
    similarity?
  }
types = element types { fieldtype* }
fieldType =
  element fieldType {
    attribute name { text },
    attribute class { text },
    attribute sortMissingLast { d:boolean },
    attribute omitNorms { d:boolean },
    attribute indexed { d:boolean }?,
    (empty | analyzer)
  }
analyzer =
  element analyzer {
    attribute class { text }?,
    tokenizer?,
    filter*
  }
tokenizer =
  element tokenizer {
    attribute class { text }
  }
filter =
  element filter {
    attribute class { text },
    attribute ignoreCase { d:boolean }?,
    attribute words { text }?,
    attribute enablePositionIncrements { d:boolean }?,
    attribute generateWordParts { d:int }?,
    attribute generateNumberParts { d:int }?,
    attribute catenateWords { d:int }?,
    attribute catenateNumbers { d:int }?,
    attribute catenateAll { d:int }?,
    attribute splitOnCaseChange { d:int }?,
    attribute protected { text }?
  }
fields = element fields { field*, dynamicField* }
field =
  element field {
    attribute name { text },
    attribute type { text },
    attribute indexed { d:boolean }?,
    attribute compressed { d:boolean }?,
    attribute stored { d:boolean }?,
    attribute required { d:boolean }?,
    attribute multiValued { d:boolean }?,
    attribute omitNorms { d:boolean }?,
    attribute termVectors { d:boolean }?
  }
dynamicField =
  element dynamicField {
    attribute name { text },
    attribute type { text },
    attribute indexed { d:boolean },
    attribute stored { d:boolean }
  }
copyField =
  element copyField {
    attribute source { text },
    attribute sku { text }
  }
similarity =
  element similarity {
    attribute class { text },
    element str {
      attribute name { text }
    }*
  }