default namespace = "http://www.brics.dk/ixwt/recipes"

start =
  element collection {
    element description { text },
    element-recipe*
  }

element-recipe =
  element recipe {
    attribute id { ID }?,
    ((element title { text },
      element date { text },
      element-ingredient*,
      element-preparation,
      element nutrition { attributes-nutrition },
      element-related*) & 
     element comment { text }?)}

element-ingredient =
  element ingredient {
    attribute name { text },
    ((attribute amount { "*" | NUMBER },
      attribute unit { text }?)
     | (element-ingredient*, element-preparation))
  }

element-preparation =
  element preparation {
    element step { text }*
  }

attributes-nutrition =
  attribute calories { NUMBER },
  attribute protein { PERCENTAGE },
  attribute carbohydrates { PERCENTAGE },
  attribute fat { PERCENTAGE },
  attribute alcohol { PERCENTAGE }?

element-related =
  element related {
    attribute ref { IDREF }
  }

PERCENTAGE = xsd:string { pattern = "([0-9]|[1-9][0-9]|100)%" }

NUMBER = xsd:decimal { minInclusive = "0" }