TRstNodeKind = enum 
  rnInner, 
  rnHeadline, 
  rnOverline, 
  rnTransition, 
  rnParagraph, 
  rnBulletList, 
  rnBulletItem, 
  rnEnumList, 
  rnEnumItem, 
  rnDefList, 
  rnDefItem, 
  rnDefName, 
  rnDefBody, 
  rnFieldList, 
  rnField, 
  rnFieldName, 
  rnFieldBody, 
  rnOptionList, rnOptionListItem, rnOptionGroup, rnOption, rnOptionString, 
  rnOptionArgument, rnDescription, rnLiteralBlock, rnQuotedLiteralBlock, rnLineBlock, 
  rnLineBlockItem, 
  rnBlockQuote, 
  rnTable, rnGridTable, rnTableRow, rnTableHeaderCell, rnTableDataCell, rnLabel, 
  rnFootnote, 
  rnCitation, 
  rnStandaloneHyperlink, rnHyperlink, rnRef, rnDirective, 
  rnDirArg, rnRaw, rnTitle, rnContents, rnImage, rnFigure, rnCodeBlock, 
  rnRawHtml, rnRawLatex, rnContainer, 
  rnIndex, 
  rnSubstitutionDef, 
  rnGeneralRole, 
  rnSub, rnSup, rnIdx, rnEmphasis, 
  rnStrongEmphasis, 
  rnTripleEmphasis, 
  rnInterpretedText, 
  rnInlineLiteral, 
  rnSubstitutionReferences, 
  rnSmiley, 
  rnLeaf

PRstNode = ref TRstNode

TRstNodeSeq = seq[PRstNode]

TRstNode = object 
  kind*: TRstNodeKind         ## the node's kind
  text*: string               ## valid for leafs in the AST; and the title of
                              ## the document or the section
  level*: int                 ## valid for some node kinds
  sons*: TRstNodeSeq          ## the node's sons
  

proc len(n: PRstNode): int {.raises: [], tags: [].}

proc newRstNode(kind: TRstNodeKind): PRstNode {.raises: [], tags: [].}

proc newRstNode(kind: TRstNodeKind; s: string): PRstNode {.raises: [], tags: [].}

proc lastSon(n: PRstNode): PRstNode {.raises: [], tags: [].}

proc add(father, son: PRstNode) {.raises: [], tags: [].}

proc addIfNotNil(father, son: PRstNode) {.raises: [], tags: [].}

proc renderRstToRst(n: PRstNode; result: var string) {.raises: [E_Base], 
    tags: [TEffect].}