NimYAML/private/events.nim

#            NimYAML - YAML implementation in Nim
#        (c) Copyright 2015 Felix Krause
#
#    See the file "copying.txt", included in this
#    distribution, for details about the copyright.

proc `==`*(left: YamlStreamEvent, right: YamlStreamEvent): bool =
  if left.kind != right.kind: return false
  case left.kind
  of yamlStartDoc, yamlEndDoc, yamlEndMap, yamlEndSeq: result = true
  of yamlStartMap:
    result = left.mapAnchor == right.mapAnchor and left.mapTag == right.mapTag
  of yamlStartSeq:
    result = left.seqAnchor == right.seqAnchor and left.seqTag == right.seqTag
  of yamlScalar:
    result = left.scalarAnchor == right.scalarAnchor and
             left.scalarTag == right.scalarTag and
             left.scalarContent == right.scalarContent
  of yamlAlias: result = left.aliasTarget == right.aliasTarget

proc `$`*(event: YamlStreamEvent): string =
  result = $event.kind & '('
  case event.kind
  of yamlEndMap, yamlEndSeq, yamlStartDoc, yamlEndDoc: discard
  of yamlStartMap:
    result &= "tag=" & $event.mapTag
    if event.mapAnchor != yAnchorNone: result &= ", anchor=" & $event.mapAnchor
  of yamlStartSeq:
    result &= "tag=" & $event.seqTag
    if event.seqAnchor != yAnchorNone: result &= ", anchor=" & $event.seqAnchor
  of yamlScalar:
    result &= "tag=" & $event.scalarTag
    if event.scalarAnchor != yAnchorNone:
      result &= ", anchor=" & $event.scalarAnchor
    result &= ", content=\"" & event.scalarContent & '\"'
  of yamlAlias:
    result &= "aliasTarget=" & $event.aliasTarget
  result &= ")"

proc tag*(event: YamlStreamEvent): TagId =
  case event.kind
  of yamlStartMap: result = event.mapTag
  of yamlStartSeq: result = event.seqTag
  of yamlScalar: result = event.scalarTag
  else: raise newException(FieldError, "Event " & $event.kind & " has no tag")

proc startDocEvent*(): YamlStreamEvent =
  result = YamlStreamEvent(kind: yamlStartDoc)
    
proc endDocEvent*(): YamlStreamEvent =
  result = YamlStreamEvent(kind: yamlEndDoc)
    
proc startMapEvent*(tag: TagId = yTagQuestionMark,
                    anchor: AnchorId = yAnchorNone): YamlStreamEvent =
  result = YamlStreamEvent(kind: yamlStartMap, mapTag: tag, mapAnchor: anchor)
                             
proc endMapEvent*(): YamlStreamEvent =
  result = YamlStreamEvent(kind: yamlEndMap)
    
proc startSeqEvent*(tag: TagId = yTagQuestionMark,
                    anchor: AnchorId = yAnchorNone): YamlStreamEvent =
  result = YamlStreamEvent(kind: yamlStartSeq, seqTag: tag, seqAnchor: anchor)
                             
proc endSeqEvent*(): YamlStreamEvent =
  result = YamlStreamEvent(kind: yamlEndSeq)
    
proc scalarEvent*(content: string = "", tag: TagId = yTagQuestionMark,
                  anchor: AnchorId = yAnchorNone): YamlStreamEvent =
  result = YamlStreamEvent(kind: yamlScalar, scalarTag: tag,
                           scalarAnchor: anchor, scalarContent: content)

proc aliasEvent*(anchor: AnchorId): YamlStreamEvent =
  result = YamlStreamEvent(kind: yamlAlias, aliasTarget: anchor)