SqlLexer = object of BaseLexer
  filename: string

SqlNodeKind = enum
  nkNone, nkIdent, nkQuotedIdent, nkStringLit, nkBitStringLit, nkHexStringLit,
  nkIntegerLit, nkNumericLit, nkPrimaryKey, nkForeignKey, nkNotNull, nkNull,
  nkStmtList, nkDot, nkDotDot, nkPrefix, nkInfix, nkCall, nkPrGroup,
  nkColumnReference, nkReferences, nkDefault, nkCheck, nkConstraint, nkUnique,
  nkIdentity, nkColumnDef,  ## name, datatype, constraints
  nkInsert, nkUpdate, nkDelete, nkSelect, nkSelectDistinct, nkSelectColumns,
  nkSelectPair, nkAsgn, nkFrom, nkFromItemPair, nkGroup, nkLimit, nkHaving,
  nkOrder, nkJoin, nkDesc, nkUnion, nkIntersect, nkExcept, nkColumnList,
  nkValueList, nkWhere, nkCreateTable, nkCreateTableIfNotExists, nkCreateType,
  nkCreateTypeIfNotExists, nkCreateIndex, nkCreateIndexIfNotExists, nkEnumDef

SqlParseError = object of ValueError

SqlNode = ref SqlNodeObj

SqlNodeObj = object
  case kind*: SqlNodeKind    ## kind of syntax tree
  of LiteralNodes:
      strVal*: string        ## AST leaf: the identifier, numeric literal
                             ## string literal, etc.
    
  else:
      sons*: seq[SqlNode]    ## the node's children
    
  

SqlParser = object of SqlLexer
  tok: Token

proc newNode(k: SqlNodeKind): SqlNode {...}{.raises: [], tags: [].}

proc newNode(k: SqlNodeKind; s: string): SqlNode {...}{.raises: [], tags: [].}

proc newNode(k: SqlNodeKind; sons: seq[SqlNode]): SqlNode {...}{.raises: [], tags: [].}

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

proc `[]`(n: SqlNode; i: int): SqlNode {...}{.raises: [], tags: [].}

proc `[]`(n: SqlNode; i: BackwardsIndex): SqlNode {...}{.raises: [], tags: [].}

proc add(father, n: SqlNode) {...}{.raises: [], tags: [].}

proc renderSQL(n: SqlNode; upperCase = false): string {...}{.raises: [Exception],
    tags: [RootEffect].}

proc `$`(n: SqlNode): string {...}{.raises: [Exception], tags: [RootEffect].}

proc treeRepr(s: SqlNode): string {...}{.raises: [], tags: [].}

proc parseSQL(input: Stream; filename: string): SqlNode {...}{.raises: [IOError,
    OSError, IOError, OSError, ValueError, SqlParseError, Exception],
    tags: [ReadIOEffect, RootEffect, WriteIOEffect].}

proc parseSQL(input: string; filename = ""): SqlNode {...}{.
    raises: [IOError, OSError, ValueError, SqlParseError, Exception],
    tags: [ReadIOEffect, RootEffect, WriteIOEffect].}