default namespace this = "http://thaiopensource.com/ns/locating-rules/1.0"
namespace local = ""

start = locatingRules

locatingRules =  element locatingRules { common, rule* }

rule =
  \include
  # | group
  | applyFollowingRules
  | documentElement
  # | doctypePublicId
  | \namespace
  | uri
  | transformURI
  # | typeIdProcessingInstruction
  | \default
  | typeId
  # | typeIdBase
  | extensionRule
 
## Group of rules. Useful with xml:base.
group = element group { common, rule* }

\include =
  element include {
    common,
    attribute rules { xsd:anyURI }
  }

applyFollowingRules =
  element applyFollowingRules {
    common,
    attribute ruleType {
      "documentElement"
      | "doctypePublicId"
      | "namespace"
      | "uri"
      | "transformURI"
      | "typeIdProcessingInstruction"
      | "default"
    }
  }

documentElement =
  ## Matches if the prefix and/or local name of document element
  ## match the values of the prefix and localName attributes.
  element documentElement {
    common,
    nameAtts,
    targetAtt
  }

## If there's no prefix attribute, then only the local name must match.
## If there's no local name attribute, then only the prefix must match.
nameAtts = (prefixAtt, localNameAtt?) | localNameAtt

## prefix="" matches if the document element has no prefix.
prefixAtt = attribute prefix { (xsd:NCName - "xmlns") | "" }
localNameAtt = attribute localName { xsd:NCName - "xmlns" }

doctypePublicId =
  ## Matches if the document has a DOCTYPE declaration with a public
  ## identifier that, after normalization, matches the value of the
  ## publicId attribute.
  element doctypePublicId {
    common,
    attribute publicId { publicIdValue },
    targetAtt
  }

publicIdValue =
  xsd:token {
    ## Newline and tab are excluded, because pattern applies to
    ## the post-normalization value.
    pattern = "[\-'()+,./:=?;!*#@$_%a-zA-Z0-9 ]*"
  }

# This is separate from documentElement so it can be distinguished
# by applyFollowingRules.
\namespace =
  ## Matches if the document element has a namespace URI equal to the value
  ## of the ns attribute.  A document element with no namespace matches if
  ## the value of the ns attribute is the empty string.
  element namespace {
    common,
    attribute ns { xsd:string },
    targetAtt
  }

uri =
  ## Matches based on the URI of the document.
  element uri {
    common,
    (resourceAtt | patternAtt),
    targetAtt
  }

## Matches if it can be determined that the document resource is
## the same resource as that identified by the value of the resource
## attribute.  In determining this, the implementation should apply
## the semantics of the URI scheme used by the URI.
resourceAtt = attribute resource { xsd:anyURI }

## Matches if the document's URI matches the pattern specified
## by the pattern attribute.  A * in the path component matches
## zero or more characters other than / (after resolving escapes).
## If the pattern is a relative URI, it means that there must
## be some URI such that when the pattern is resolved relative
## to that URI, it matches the document's URI. Thus an empty
## pattern will always match.
patternAtt = attribute pattern { uriPattern }

## A pattern for a URI. Same syntax as a URI, except that a * in
## the path component has a special meaning.
uriPattern = xsd:anyURI

transformURI =
  ## Generates a URI for the related resource by transforming
  ## the URI of the document. Matches if the transformation
  ## yields a valid URI that identifies an existing resource.
  element transformURI {
    common,
    ## Semantics are the same as the pattern attribute of the uri element.
    attribute fromPattern { uriPattern },
    ## The result of the transformation is produced from the toPattern
    ## by replacing each * by the string that matched the corresponding
    ## * in the toPattern.  The toPattern is appended to the initial
    ## part of the document's URI that was not explicitly matched
    ## by fromPattern.
    attribute toPattern { uriPattern }
  }

\default =
  ## Always matches.
  element default {
    common,
    targetAtt
  }

## A document can be mapped onto a URI either indirectly via a typeId
## or directly.
targetAtt = uriAtt | typeIdAtt

## Specifies the URI of the related resource.
## xml:base is used if it's relative.
uriAtt = attribute uri { xsd:anyURI }

## Specifies an identifier of the type of document. typeId and
## typeIdBase rules will be used to map this to a URI.
typeIdAtt = attribute typeId { typeIdValue }

## A type identifier can be anything convenient (e.g. a public identifier,
## a URL or just a string with no formal structure).  Whitespace is
## normalized like a public identifier before comparing type identifiers
## for equality.
typeIdValue = xsd:token

typeIdProcessingInstruction =
  ## Matches if there's a processing instruction in the prolog
  ## before any DOCTYPE declaration whose target is the value of
  ## the target attribute.  The value of the processing instruction
  ## is interpreted as a typeId, which will be mapped to a
  ## URI as normal.
  element typeIdProcessingInstruction {
    common,
    attribute target { xsd:NCName }
  }

typeId =
  ## Maps a typeId onto a URI.
  element typeId {
    common,
    attribute id { typeIdValue },
    targetAtt
  }

typeIdBase =
  ## Used to map a typeId onto a URI. First, any URI reserved characters
  ## are URI encoded. If the append attribute is specified, it is appended.
  ## This is then treated as a URI. If relative, it is resolved using
  ## the applicable base URI as usual.  If the resulting URI identifies
  ## an existing resource, then the typeId is mapped to this resource.
  ## This is intended to be useful with file URIs.
  element typeIdBase {
    common,
    attribute append { xsd:string }?
  }

extensionRule =
  element * - this:* {
    attribute * { text }*, (text|anyElement)*
  }

anyElement = element * { attribute * { text }*, (text|anyElement)* }

common = 
  # attribute xml:base { xsd:anyURI }?,
  attribute * - (xml:base|this:*|local:*) { text }*
