JetFile: Graph.kt
  PACKAGE_DIRECTIVE
    <empty list>
  CLASS
    PsiElement(class)('class')
    PsiWhiteSpace(' ')
    PsiElement(IDENTIFIER)('Vertex')
    TYPE_PARAMETER_LIST
      PsiElement(LT)('<')
      TYPE_PARAMETER
        PsiElement(IDENTIFIER)('V')
      PsiElement(GT)('>')
    VALUE_PARAMETER_LIST
      PsiElement(LPAR)('(')
      VALUE_PARAMETER
        PsiElement(val)('val')
        PsiWhiteSpace(' ')
        PsiElement(IDENTIFIER)('data')
        PsiWhiteSpace(' ')
        PsiElement(COLON)(':')
        PsiWhiteSpace(' ')
        TYPE_REFERENCE
          USER_TYPE
            REFERENCE_EXPRESSION
              PsiElement(IDENTIFIER)('V')
      PsiElement(RPAR)(')')
  PsiWhiteSpace('\n\n')
  CLASS
    PsiElement(class)('class')
    PsiWhiteSpace(' ')
    PsiElement(IDENTIFIER)('Edge')
    TYPE_PARAMETER_LIST
      PsiElement(LT)('<')
      TYPE_PARAMETER
        PsiElement(IDENTIFIER)('V')
      PsiElement(COMMA)(',')
      PsiWhiteSpace(' ')
      TYPE_PARAMETER
        PsiElement(IDENTIFIER)('E')
      PsiElement(GT)('>')
    VALUE_PARAMETER_LIST
      PsiElement(LPAR)('(')
      VALUE_PARAMETER
        PsiElement(val)('val')
        PsiWhiteSpace(' ')
        PsiElement(IDENTIFIER)('from')
        PsiWhiteSpace(' ')
        PsiElement(COLON)(':')
        PsiWhiteSpace(' ')
        TYPE_REFERENCE
          USER_TYPE
            REFERENCE_EXPRESSION
              PsiElement(IDENTIFIER)('V')
      PsiElement(COMMA)(',')
      PsiWhiteSpace(' ')
      VALUE_PARAMETER
        PsiElement(val)('val')
        PsiWhiteSpace(' ')
        PsiElement(IDENTIFIER)('data')
        PsiWhiteSpace(' ')
        PsiElement(COLON)(':')
        PsiWhiteSpace(' ')
        TYPE_REFERENCE
          USER_TYPE
            REFERENCE_EXPRESSION
              PsiElement(IDENTIFIER)('E')
      PsiElement(COMMA)(',')
      PsiWhiteSpace(' ')
      VALUE_PARAMETER
        PsiElement(val)('val')
        PsiWhiteSpace(' ')
        PsiElement(IDENTIFIER)('to')
        PsiWhiteSpace(' ')
        PsiElement(COLON)(':')
        PsiWhiteSpace(' ')
        TYPE_REFERENCE
          USER_TYPE
            REFERENCE_EXPRESSION
              PsiElement(IDENTIFIER)('V')
      PsiElement(RPAR)(')')
  PsiWhiteSpace('\n\n')
  CLASS
    PsiElement(class)('class')
    PsiWhiteSpace(' ')
    PsiElement(IDENTIFIER)('Graph')
    TYPE_PARAMETER_LIST
      PsiElement(LT)('<')
      TYPE_PARAMETER
        PsiElement(IDENTIFIER)('V')
      PsiElement(COMMA)(',')
      PsiWhiteSpace(' ')
      TYPE_PARAMETER
        PsiElement(IDENTIFIER)('E')
      PsiElement(GT)('>')
    PsiWhiteSpace(' ')
    CLASS_BODY
      PsiElement(LBRACE)('{')
      PsiWhiteSpace('\n\n  ')
      PROPERTY
        MODIFIER_LIST
          PsiElement(private)('private')
        PsiWhiteSpace(' ')
        PsiElement(val)('val')
        PsiWhiteSpace(' ')
        PsiElement(IDENTIFIER)('mutableEdges')
        PsiWhiteSpace(' ')
        PsiElement(EQ)('=')
        PsiWhiteSpace(' ')
        CALL_EXPRESSION
          REFERENCE_EXPRESSION
            PsiElement(IDENTIFIER)('ArrayList')
          TYPE_ARGUMENT_LIST
            PsiElement(LT)('<')
            TYPE_PROJECTION
              TYPE_REFERENCE
                USER_TYPE
                  REFERENCE_EXPRESSION
                    PsiElement(IDENTIFIER)('Edge')
                  TYPE_ARGUMENT_LIST
                    PsiElement(LT)('<')
                    TYPE_PROJECTION
                      TYPE_REFERENCE
                        USER_TYPE
                          REFERENCE_EXPRESSION
                            PsiElement(IDENTIFIER)('V')
                    PsiElement(COMMA)(',')
                    PsiWhiteSpace(' ')
                    TYPE_PROJECTION
                      TYPE_REFERENCE
                        USER_TYPE
                          REFERENCE_EXPRESSION
                            PsiElement(IDENTIFIER)('E')
                    PsiElement(GT)('>')
            PsiElement(GT)('>')
          VALUE_ARGUMENT_LIST
            PsiElement(LPAR)('(')
            PsiElement(RPAR)(')')
      PsiWhiteSpace(' ')
      PsiComment(EOL_COMMENT)('// type is ArrayList, but I want IMutableList')
      PsiWhiteSpace('\n')
      PsiComment(BLOCK_COMMENT)('/* options:\n    private val edges : IMutableList<Edge<V, E>> = ArrayList<Edge<V, E>>()\n    private val edges : IMutableList<Edge<V, E>> = ArrayList() // not an erasure, but a request to infer parameters\n*/')
      PsiWhiteSpace('\n\n  ')
      PROPERTY
        MODIFIER_LIST
          PsiElement(private)('private')
        PsiWhiteSpace(' ')
        PsiElement(val)('val')
        PsiWhiteSpace(' ')
        PsiElement(IDENTIFIER)('mutableVertices')
        PsiWhiteSpace(' ')
        PsiElement(EQ)('=')
        PsiWhiteSpace(' ')
        CALL_EXPRESSION
          REFERENCE_EXPRESSION
            PsiElement(IDENTIFIER)('HashSet')
          TYPE_ARGUMENT_LIST
            PsiElement(LT)('<')
            TYPE_PROJECTION
              TYPE_REFERENCE
                USER_TYPE
                  REFERENCE_EXPRESSION
                    PsiElement(IDENTIFIER)('Vertex')
                  TYPE_ARGUMENT_LIST
                    PsiElement(LT)('<')
                    TYPE_PROJECTION
                      TYPE_REFERENCE
                        USER_TYPE
                          REFERENCE_EXPRESSION
                            PsiElement(IDENTIFIER)('V')
                    PsiElement(GT)('>')
            PsiElement(GT)('>')
          VALUE_ARGUMENT_LIST
            PsiElement(LPAR)('(')
            PsiElement(RPAR)(')')
      PsiWhiteSpace('\n\n  ')
      PROPERTY
        PsiElement(val)('val')
        PsiWhiteSpace(' ')
        PsiElement(IDENTIFIER)('edges')
        PsiWhiteSpace(' ')
        PsiElement(COLON)(':')
        PsiWhiteSpace(' ')
        TYPE_REFERENCE
          USER_TYPE
            REFERENCE_EXPRESSION
              PsiElement(IDENTIFIER)('IList')
            TYPE_ARGUMENT_LIST
              PsiElement(LT)('<')
              TYPE_PROJECTION
                TYPE_REFERENCE
                  USER_TYPE
                    REFERENCE_EXPRESSION
                      PsiElement(IDENTIFIER)('Edge')
                    TYPE_ARGUMENT_LIST
                      PsiElement(LT)('<')
                      TYPE_PROJECTION
                        TYPE_REFERENCE
                          USER_TYPE
                            REFERENCE_EXPRESSION
                              PsiElement(IDENTIFIER)('V')
                      PsiElement(COMMA)(',')
                      PsiWhiteSpace(' ')
                      TYPE_PROJECTION
                        TYPE_REFERENCE
                          USER_TYPE
                            REFERENCE_EXPRESSION
                              PsiElement(IDENTIFIER)('E')
                      PsiElement(GT)('>')
              PsiElement(GT)('>')
        PsiWhiteSpace(' ')
        PsiElement(EQ)('=')
        PsiWhiteSpace(' ')
        REFERENCE_EXPRESSION
          PsiElement(IDENTIFIER)('mutableEdges')
        PsiElement(SEMICOLON)(';')
      PsiWhiteSpace('\n  ')
      PROPERTY
        PsiElement(val)('val')
        PsiWhiteSpace(' ')
        PsiElement(IDENTIFIER)('vertices')
        PsiWhiteSpace(' ')
        PsiElement(COLON)(':')
        PsiWhiteSpace(' ')
        TYPE_REFERENCE
          USER_TYPE
            REFERENCE_EXPRESSION
              PsiElement(IDENTIFIER)('ISet')
            TYPE_ARGUMENT_LIST
              PsiElement(LT)('<')
              TYPE_PROJECTION
                TYPE_REFERENCE
                  USER_TYPE
                    REFERENCE_EXPRESSION
                      PsiElement(IDENTIFIER)('Edge')
                    TYPE_ARGUMENT_LIST
                      PsiElement(LT)('<')
                      TYPE_PROJECTION
                        TYPE_REFERENCE
                          USER_TYPE
                            REFERENCE_EXPRESSION
                              PsiElement(IDENTIFIER)('V')
                      PsiElement(COMMA)(',')
                      PsiWhiteSpace(' ')
                      TYPE_PROJECTION
                        TYPE_REFERENCE
                          USER_TYPE
                            REFERENCE_EXPRESSION
                              PsiElement(IDENTIFIER)('E')
                      PsiElement(GT)('>')
              PsiElement(GT)('>')
        PsiWhiteSpace(' ')
        PsiElement(EQ)('=')
        PsiWhiteSpace(' ')
        REFERENCE_EXPRESSION
          PsiElement(IDENTIFIER)('mutableVertices')
        PsiElement(SEMICOLON)(';')
      PsiWhiteSpace('\n\n  ')
      FUN
        PsiElement(fun)('fun')
        PsiWhiteSpace(' ')
        PsiElement(IDENTIFIER)('addEdge')
        VALUE_PARAMETER_LIST
          PsiElement(LPAR)('(')
          VALUE_PARAMETER
            PsiElement(IDENTIFIER)('from')
            PsiWhiteSpace(' ')
            PsiElement(COLON)(':')
            PsiWhiteSpace(' ')
            TYPE_REFERENCE
              USER_TYPE
                REFERENCE_EXPRESSION
                  PsiElement(IDENTIFIER)('V')
          PsiElement(COMMA)(',')
          PsiWhiteSpace(' ')
          VALUE_PARAMETER
            PsiElement(IDENTIFIER)('data')
            PsiWhiteSpace(' ')
            PsiElement(COLON)(':')
            PsiWhiteSpace(' ')
            TYPE_REFERENCE
              USER_TYPE
                REFERENCE_EXPRESSION
                  PsiElement(IDENTIFIER)('E')
          PsiElement(COMMA)(',')
          PsiWhiteSpace(' ')
          VALUE_PARAMETER
            PsiElement(IDENTIFIER)('to')
            PsiWhiteSpace(' ')
            PsiElement(COLON)(':')
            PsiWhiteSpace(' ')
            TYPE_REFERENCE
              USER_TYPE
                REFERENCE_EXPRESSION
                  PsiElement(IDENTIFIER)('V')
          PsiElement(RPAR)(')')
        PsiWhiteSpace(' ')
        BLOCK
          PsiElement(LBRACE)('{')
          PsiWhiteSpace('\n    ')
          DOT_QUALIFIED_EXPRESSION
            REFERENCE_EXPRESSION
              PsiElement(IDENTIFIER)('mutableEdges')
            PsiElement(DOT)('.')
            CALL_EXPRESSION
              REFERENCE_EXPRESSION
                PsiElement(IDENTIFIER)('add')
              VALUE_ARGUMENT_LIST
                PsiElement(LPAR)('(')
                VALUE_ARGUMENT
                  CALL_EXPRESSION
                    REFERENCE_EXPRESSION
                      PsiElement(IDENTIFIER)('Edge')
                    VALUE_ARGUMENT_LIST
                      PsiElement(LPAR)('(')
                      VALUE_ARGUMENT
                        REFERENCE_EXPRESSION
                          PsiElement(IDENTIFIER)('from')
                      PsiElement(COMMA)(',')
                      PsiWhiteSpace(' ')
                      VALUE_ARGUMENT
                        REFERENCE_EXPRESSION
                          PsiElement(IDENTIFIER)('data')
                      PsiElement(COMMA)(',')
                      PsiWhiteSpace(' ')
                      VALUE_ARGUMENT
                        REFERENCE_EXPRESSION
                          PsiElement(IDENTIFIER)('to')
                      PsiElement(RPAR)(')')
                PsiElement(RPAR)(')')
          PsiWhiteSpace(' ')
          PsiComment(EOL_COMMENT)('// constructor parameters are inferred')
          PsiWhiteSpace('\n  ')
          PsiElement(RBRACE)('}')
      PsiWhiteSpace('\n  ')
      FUN
        PsiElement(fun)('fun')
        PsiWhiteSpace(' ')
        PsiElement(IDENTIFIER)('addVertex')
        VALUE_PARAMETER_LIST
          PsiElement(LPAR)('(')
          VALUE_PARAMETER
            PsiElement(IDENTIFIER)('v')
            PsiWhiteSpace(' ')
            PsiElement(COLON)(':')
            PsiWhiteSpace(' ')
            TYPE_REFERENCE
              USER_TYPE
                REFERENCE_EXPRESSION
                  PsiElement(IDENTIFIER)('V')
          PsiElement(RPAR)(')')
        PsiWhiteSpace(' ')
        BLOCK
          PsiElement(LBRACE)('{')
          PsiWhiteSpace('\n    ')
          DOT_QUALIFIED_EXPRESSION
            REFERENCE_EXPRESSION
              PsiElement(IDENTIFIER)('mutableEdges')
            PsiElement(DOT)('.')
            CALL_EXPRESSION
              REFERENCE_EXPRESSION
                PsiElement(IDENTIFIER)('add')
              VALUE_ARGUMENT_LIST
                PsiElement(LPAR)('(')
                VALUE_ARGUMENT
                  CALL_EXPRESSION
                    REFERENCE_EXPRESSION
                      PsiElement(IDENTIFIER)('Edge')
                    VALUE_ARGUMENT_LIST
                      PsiElement(LPAR)('(')
                      VALUE_ARGUMENT
                        REFERENCE_EXPRESSION
                          PsiElement(IDENTIFIER)('from')
                      PsiElement(COMMA)(',')
                      PsiWhiteSpace(' ')
                      VALUE_ARGUMENT
                        REFERENCE_EXPRESSION
                          PsiElement(IDENTIFIER)('data')
                      PsiElement(COMMA)(',')
                      PsiWhiteSpace(' ')
                      VALUE_ARGUMENT
                        REFERENCE_EXPRESSION
                          PsiElement(IDENTIFIER)('to')
                      PsiElement(RPAR)(')')
                PsiElement(RPAR)(')')
          PsiWhiteSpace(' ')
          PsiComment(EOL_COMMENT)('// constructor parameters are inferred')
          PsiWhiteSpace('\n  ')
          PsiElement(RBRACE)('}')
      PsiWhiteSpace('\n\n  ')
      FUN
        PsiElement(fun)('fun')
        PsiWhiteSpace(' ')
        PsiElement(IDENTIFIER)('neighbours')
        VALUE_PARAMETER_LIST
          PsiElement(LPAR)('(')
          VALUE_PARAMETER
            PsiElement(IDENTIFIER)('v')
            PsiWhiteSpace(' ')
            PsiElement(COLON)(':')
            PsiWhiteSpace(' ')
            TYPE_REFERENCE
              USER_TYPE
                REFERENCE_EXPRESSION
                  PsiElement(IDENTIFIER)('Vertex')
                TYPE_ARGUMENT_LIST
                  PsiElement(LT)('<')
                  TYPE_PROJECTION
                    TYPE_REFERENCE
                      USER_TYPE
                        REFERENCE_EXPRESSION
                          PsiElement(IDENTIFIER)('V')
                  PsiElement(GT)('>')
          PsiElement(RPAR)(')')
        PsiWhiteSpace(' ')
        PsiElement(EQ)('=')
        PsiWhiteSpace(' ')
        DOT_QUALIFIED_EXPRESSION
          DOT_QUALIFIED_EXPRESSION
            REFERENCE_EXPRESSION
              PsiElement(IDENTIFIER)('edges')
            PsiElement(DOT)('.')
            CALL_EXPRESSION
              REFERENCE_EXPRESSION
                PsiElement(IDENTIFIER)('filter')
              FUNCTION_LITERAL_ARGUMENT
                FUNCTION_LITERAL_EXPRESSION
                  FUNCTION_LITERAL
                    PsiElement(LBRACE)('{')
                    BLOCK
                      BINARY_EXPRESSION
                        DOT_QUALIFIED_EXPRESSION
                          REFERENCE_EXPRESSION
                            PsiElement(IDENTIFIER)('it')
                          PsiElement(DOT)('.')
                          REFERENCE_EXPRESSION
                            PsiElement(IDENTIFIER)('from')
                        PsiWhiteSpace(' ')
                        OPERATION_REFERENCE
                          PsiElement(EQEQ)('==')
                        PsiWhiteSpace(' ')
                        REFERENCE_EXPRESSION
                          PsiElement(IDENTIFIER)('v')
                    PsiElement(RBRACE)('}')
          PsiElement(DOT)('.')
          CALL_EXPRESSION
            REFERENCE_EXPRESSION
              PsiElement(IDENTIFIER)('map')
            FUNCTION_LITERAL_ARGUMENT
              FUNCTION_LITERAL_EXPRESSION
                FUNCTION_LITERAL
                  PsiElement(LBRACE)('{')
                  BLOCK
                    DOT_QUALIFIED_EXPRESSION
                      REFERENCE_EXPRESSION
                        PsiElement(IDENTIFIER)('it')
                      PsiElement(DOT)('.')
                      REFERENCE_EXPRESSION
                        PsiElement(IDENTIFIER)('to')
                  PsiElement(RBRACE)('}')
      PsiWhiteSpace(' ')
      PsiComment(EOL_COMMENT)('// type is IIterable<Vertex<V>>')
      PsiWhiteSpace('\n\n  ')
      FUN
        PsiElement(fun)('fun')
        PsiWhiteSpace(' ')
        PsiElement(IDENTIFIER)('dfs')
        VALUE_PARAMETER_LIST
          PsiElement(LPAR)('(')
          VALUE_PARAMETER
            PsiElement(IDENTIFIER)('handler')
            PsiWhiteSpace(' ')
            PsiElement(COLON)(':')
            PsiWhiteSpace('  ')
            TYPE_REFERENCE
              FUNCTION_TYPE
                VALUE_PARAMETER_LIST
                  PsiElement(LPAR)('(')
                  VALUE_PARAMETER
                    TYPE_REFERENCE
                      USER_TYPE
                        REFERENCE_EXPRESSION
                          PsiElement(IDENTIFIER)('V')
                  PsiElement(RPAR)(')')
                PsiWhiteSpace(' ')
                PsiElement(ARROW)('->')
                PsiWhiteSpace(' ')
                TYPE_REFERENCE
                  USER_TYPE
                    REFERENCE_EXPRESSION
                      PsiElement(IDENTIFIER)('Unit')
          PsiElement(RPAR)(')')
        PsiWhiteSpace(' ')
        BLOCK
          PsiElement(LBRACE)('{')
          PsiWhiteSpace('\n    ')
          PROPERTY
            PsiElement(val)('val')
            PsiWhiteSpace(' ')
            PsiElement(IDENTIFIER)('visited')
            PsiWhiteSpace(' ')
            PsiElement(EQ)('=')
            PsiWhiteSpace(' ')
            CALL_EXPRESSION
              REFERENCE_EXPRESSION
                PsiElement(IDENTIFIER)('HashSet')
              TYPE_ARGUMENT_LIST
                PsiElement(LT)('<')
                TYPE_PROJECTION
                  TYPE_REFERENCE
                    USER_TYPE
                      REFERENCE_EXPRESSION
                        PsiElement(IDENTIFIER)('Vertex')
                      TYPE_ARGUMENT_LIST
                        PsiElement(LT)('<')
                        TYPE_PROJECTION
                          TYPE_REFERENCE
                            USER_TYPE
                              REFERENCE_EXPRESSION
                                PsiElement(IDENTIFIER)('V')
                        PsiElement(GT)('>')
                PsiElement(GT)('>')
              VALUE_ARGUMENT_LIST
                PsiElement(LPAR)('(')
                PsiElement(RPAR)(')')
          PsiWhiteSpace('\n    ')
          DOT_QUALIFIED_EXPRESSION
            REFERENCE_EXPRESSION
              PsiElement(IDENTIFIER)('vertices')
            PsiElement(DOT)('.')
            CALL_EXPRESSION
              REFERENCE_EXPRESSION
                PsiElement(IDENTIFIER)('foreach')
              FUNCTION_LITERAL_ARGUMENT
                FUNCTION_LITERAL_EXPRESSION
                  FUNCTION_LITERAL
                    PsiElement(LBRACE)('{')
                    BLOCK
                      CALL_EXPRESSION
                        REFERENCE_EXPRESSION
                          PsiElement(IDENTIFIER)('dfs')
                        VALUE_ARGUMENT_LIST
                          PsiElement(LPAR)('(')
                          VALUE_ARGUMENT
                            REFERENCE_EXPRESSION
                              PsiElement(IDENTIFIER)('it')
                          PsiElement(COMMA)(',')
                          PsiWhiteSpace(' ')
                          VALUE_ARGUMENT
                            REFERENCE_EXPRESSION
                              PsiElement(IDENTIFIER)('visited')
                          PsiElement(COMMA)(',')
                          PsiWhiteSpace(' ')
                          VALUE_ARGUMENT
                            REFERENCE_EXPRESSION
                              PsiElement(IDENTIFIER)('handler')
                          PsiElement(RPAR)(')')
                    PsiElement(RBRACE)('}')
          PsiWhiteSpace('\n\n    ')
          FUN
            PsiElement(fun)('fun')
            PsiWhiteSpace(' ')
            PsiElement(IDENTIFIER)('dfs')
            VALUE_PARAMETER_LIST
              PsiElement(LPAR)('(')
              VALUE_PARAMETER
                PsiElement(IDENTIFIER)('current')
                PsiWhiteSpace(' ')
                PsiElement(COLON)(':')
                PsiWhiteSpace(' ')
                TYPE_REFERENCE
                  USER_TYPE
                    REFERENCE_EXPRESSION
                      PsiElement(IDENTIFIER)('Vertex')
                    TYPE_ARGUMENT_LIST
                      PsiElement(LT)('<')
                      TYPE_PROJECTION
                        TYPE_REFERENCE
                          USER_TYPE
                            REFERENCE_EXPRESSION
                              PsiElement(IDENTIFIER)('V')
                      PsiElement(GT)('>')
              PsiElement(COMMA)(',')
              PsiWhiteSpace(' ')
              VALUE_PARAMETER
                PsiElement(IDENTIFIER)('visited')
                PsiWhiteSpace(' ')
                PsiElement(COLON)(':')
                PsiWhiteSpace(' ')
                TYPE_REFERENCE
                  USER_TYPE
                    REFERENCE_EXPRESSION
                      PsiElement(IDENTIFIER)('ISet')
                    TYPE_ARGUMENT_LIST
                      PsiElement(LT)('<')
                      TYPE_PROJECTION
                        TYPE_REFERENCE
                          USER_TYPE
                            REFERENCE_EXPRESSION
                              PsiElement(IDENTIFIER)('Vertex')
                            TYPE_ARGUMENT_LIST
                              PsiElement(LT)('<')
                              TYPE_PROJECTION
                                TYPE_REFERENCE
                                  USER_TYPE
                                    REFERENCE_EXPRESSION
                                      PsiElement(IDENTIFIER)('V')
                              PsiElement(GT)('>')
                      PsiElement(GT)('>')
              PsiElement(COMMA)(',')
              PsiWhiteSpace(' ')
              VALUE_PARAMETER
                PsiElement(IDENTIFIER)('handler')
                PsiWhiteSpace(' ')
                PsiElement(COLON)(':')
                PsiWhiteSpace('  ')
                TYPE_REFERENCE
                  FUNCTION_TYPE
                    VALUE_PARAMETER_LIST
                      PsiElement(LPAR)('(')
                      VALUE_PARAMETER
                        TYPE_REFERENCE
                          USER_TYPE
                            REFERENCE_EXPRESSION
                              PsiElement(IDENTIFIER)('V')
                      PsiElement(RPAR)(')')
                    PsiWhiteSpace(' ')
                    PsiElement(ARROW)('->')
                    PsiWhiteSpace(' ')
                    TYPE_REFERENCE
                      USER_TYPE
                        REFERENCE_EXPRESSION
                          PsiElement(IDENTIFIER)('Unit')
              PsiElement(RPAR)(')')
            PsiWhiteSpace(' ')
            BLOCK
              PsiElement(LBRACE)('{')
              PsiWhiteSpace('\n      ')
              IF
                PsiElement(if)('if')
                PsiWhiteSpace(' ')
                PsiElement(LPAR)('(')
                CONDITION
                  PREFIX_EXPRESSION
                    OPERATION_REFERENCE
                      PsiElement(EXCL)('!')
                    DOT_QUALIFIED_EXPRESSION
                      REFERENCE_EXPRESSION
                        PsiElement(IDENTIFIER)('visited')
                      PsiElement(DOT)('.')
                      CALL_EXPRESSION
                        REFERENCE_EXPRESSION
                          PsiElement(IDENTIFIER)('add')
                        VALUE_ARGUMENT_LIST
                          PsiElement(LPAR)('(')
                          VALUE_ARGUMENT
                            REFERENCE_EXPRESSION
                              PsiElement(IDENTIFIER)('current')
                          PsiElement(RPAR)(')')
                PsiElement(RPAR)(')')
                PsiWhiteSpace('\n        ')
                THEN
                  RETURN
                    PsiElement(return)('return')
              PsiWhiteSpace('\n      ')
              CALL_EXPRESSION
                REFERENCE_EXPRESSION
                  PsiElement(IDENTIFIER)('handler')
                VALUE_ARGUMENT_LIST
                  PsiElement(LPAR)('(')
                  VALUE_ARGUMENT
                    REFERENCE_EXPRESSION
                      PsiElement(IDENTIFIER)('current')
                  PsiElement(RPAR)(')')
              PsiWhiteSpace('\n      ')
              DOT_QUALIFIED_EXPRESSION
                CALL_EXPRESSION
                  REFERENCE_EXPRESSION
                    PsiElement(IDENTIFIER)('neighbours')
                  VALUE_ARGUMENT_LIST
                    PsiElement(LPAR)('(')
                    VALUE_ARGUMENT
                      REFERENCE_EXPRESSION
                        PsiElement(IDENTIFIER)('current')
                    PsiElement(RPAR)(')')
                PsiElement(DOT)('.')
                CALL_EXPRESSION
                  REFERENCE_EXPRESSION
                    PsiElement(IDENTIFIER)('foreach')
                  FUNCTION_LITERAL_ARGUMENT
                    FUNCTION_LITERAL_EXPRESSION
                      FUNCTION_LITERAL
                        PsiElement(LBRACE)('{')
                        BLOCK
                          CALL_EXPRESSION
                            REFERENCE_EXPRESSION
                              PsiElement(IDENTIFIER)('dfs')
                            VALUE_ARGUMENT_LIST
                              PsiElement(LPAR)('(')
                              VALUE_ARGUMENT
                                REFERENCE_EXPRESSION
                                  PsiElement(IDENTIFIER)('it')
                              PsiElement(COMMA)(',')
                              PsiWhiteSpace(' ')
                              VALUE_ARGUMENT
                                REFERENCE_EXPRESSION
                                  PsiElement(IDENTIFIER)('visited')
                              PsiElement(COMMA)(',')
                              PsiWhiteSpace(' ')
                              VALUE_ARGUMENT
                                REFERENCE_EXPRESSION
                                  PsiElement(IDENTIFIER)('handler')
                              PsiElement(RPAR)(')')
                        PsiElement(RBRACE)('}')
              PsiWhiteSpace('\n    ')
              PsiElement(RBRACE)('}')
          PsiWhiteSpace('\n  ')
          PsiElement(RBRACE)('}')
      PsiWhiteSpace('\n\n  ')
      FUN
        MODIFIER_LIST
          PsiElement(public)('public')
        PsiWhiteSpace(' ')
        PsiElement(fun)('fun')
        PsiWhiteSpace(' ')
        PsiElement(IDENTIFIER)('traverse')
        VALUE_PARAMETER_LIST
          PsiElement(LPAR)('(')
          VALUE_PARAMETER
            PsiElement(IDENTIFIER)('pending')
            PsiWhiteSpace(' ')
            PsiElement(COLON)(':')
            PsiWhiteSpace(' ')
            TYPE_REFERENCE
              USER_TYPE
                REFERENCE_EXPRESSION
                  PsiElement(IDENTIFIER)('IPushPop')
                TYPE_ARGUMENT_LIST
                  PsiElement(LT)('<')
                  TYPE_PROJECTION
                    TYPE_REFERENCE
                      USER_TYPE
                        REFERENCE_EXPRESSION
                          PsiElement(IDENTIFIER)('Vertex')
                        TYPE_ARGUMENT_LIST
                          PsiElement(LT)('<')
                          TYPE_PROJECTION
                            TYPE_REFERENCE
                              USER_TYPE
                                REFERENCE_EXPRESSION
                                  PsiElement(IDENTIFIER)('V')
                          PsiElement(GT)('>')
                  PsiElement(GT)('>')
          PsiElement(COMMA)(',')
          PsiWhiteSpace(' ')
          VALUE_PARAMETER
            PsiElement(IDENTIFIER)('visited')
            PsiWhiteSpace(' ')
            PsiElement(COLON)(':')
            PsiWhiteSpace(' ')
            TYPE_REFERENCE
              USER_TYPE
                REFERENCE_EXPRESSION
                  PsiElement(IDENTIFIER)('ISet')
                TYPE_ARGUMENT_LIST
                  PsiElement(LT)('<')
                  TYPE_PROJECTION
                    TYPE_REFERENCE
                      USER_TYPE
                        REFERENCE_EXPRESSION
                          PsiElement(IDENTIFIER)('Vertex')
                        TYPE_ARGUMENT_LIST
                          PsiElement(LT)('<')
                          TYPE_PROJECTION
                            TYPE_REFERENCE
                              USER_TYPE
                                REFERENCE_EXPRESSION
                                  PsiElement(IDENTIFIER)('V')
                          PsiElement(GT)('>')
                  PsiElement(GT)('>')
          PsiElement(COMMA)(',')
          PsiWhiteSpace(' ')
          VALUE_PARAMETER
            PsiElement(IDENTIFIER)('handler')
            PsiWhiteSpace(' ')
            PsiElement(COLON)(':')
            PsiWhiteSpace('  ')
            TYPE_REFERENCE
              FUNCTION_TYPE
                VALUE_PARAMETER_LIST
                  PsiElement(LPAR)('(')
                  VALUE_PARAMETER
                    TYPE_REFERENCE
                      USER_TYPE
                        REFERENCE_EXPRESSION
                          PsiElement(IDENTIFIER)('V')
                  PsiElement(RPAR)(')')
                PsiWhiteSpace(' ')
                PsiElement(ARROW)('->')
                PsiWhiteSpace(' ')
                TYPE_REFERENCE
                  USER_TYPE
                    REFERENCE_EXPRESSION
                      PsiElement(IDENTIFIER)('Unit')
          PsiElement(RPAR)(')')
        PsiWhiteSpace(' ')
        BLOCK
          PsiElement(LBRACE)('{')
          PsiWhiteSpace('\n    ')
          DOT_QUALIFIED_EXPRESSION
            REFERENCE_EXPRESSION
              PsiElement(IDENTIFIER)('vertices')
            PsiElement(DOT)('.')
            CALL_EXPRESSION
              REFERENCE_EXPRESSION
                PsiElement(IDENTIFIER)('foreach')
              PsiWhiteSpace(' ')
              FUNCTION_LITERAL_ARGUMENT
                FUNCTION_LITERAL_EXPRESSION
                  FUNCTION_LITERAL
                    PsiElement(LBRACE)('{')
                    PsiWhiteSpace('\n      ')
                    BLOCK
                      IF
                        PsiElement(if)('if')
                        PsiWhiteSpace(' ')
                        PsiElement(LPAR)('(')
                        CONDITION
                          PREFIX_EXPRESSION
                            OPERATION_REFERENCE
                              PsiElement(EXCL)('!')
                            DOT_QUALIFIED_EXPRESSION
                              REFERENCE_EXPRESSION
                                PsiElement(IDENTIFIER)('visited')
                              PsiElement(DOT)('.')
                              CALL_EXPRESSION
                                REFERENCE_EXPRESSION
                                  PsiElement(IDENTIFIER)('add')
                                VALUE_ARGUMENT_LIST
                                  PsiElement(LPAR)('(')
                                  VALUE_ARGUMENT
                                    REFERENCE_EXPRESSION
                                      PsiElement(IDENTIFIER)('it')
                                  PsiElement(RPAR)(')')
                        PsiElement(RPAR)(')')
                        PsiWhiteSpace('\n        ')
                        THEN
                          CONTINUE
                            PsiElement(continue)('continue')
                      PsiWhiteSpace('\n      ')
                      DOT_QUALIFIED_EXPRESSION
                        REFERENCE_EXPRESSION
                          PsiElement(IDENTIFIER)('pending')
                        PsiElement(DOT)('.')
                        CALL_EXPRESSION
                          REFERENCE_EXPRESSION
                            PsiElement(IDENTIFIER)('push')
                          VALUE_ARGUMENT_LIST
                            PsiElement(LPAR)('(')
                            VALUE_ARGUMENT
                              REFERENCE_EXPRESSION
                                PsiElement(IDENTIFIER)('it')
                            PsiElement(RPAR)(')')
                      PsiWhiteSpace('\n      ')
                      WHILE
                        PsiElement(while)('while')
                        PsiWhiteSpace(' ')
                        PsiElement(LPAR)('(')
                        CONDITION
                          PREFIX_EXPRESSION
                            OPERATION_REFERENCE
                              PsiElement(EXCL)('!')
                            DOT_QUALIFIED_EXPRESSION
                              REFERENCE_EXPRESSION
                                PsiElement(IDENTIFIER)('pending')
                              PsiElement(DOT)('.')
                              REFERENCE_EXPRESSION
                                PsiElement(IDENTIFIER)('isEmpty')
                        PsiElement(RPAR)(')')
                        PsiWhiteSpace(' ')
                        BODY
                          BLOCK
                            PsiElement(LBRACE)('{')
                            PsiWhiteSpace('\n        ')
                            PROPERTY
                              PsiElement(val)('val')
                              PsiWhiteSpace(' ')
                              PsiElement(IDENTIFIER)('current')
                              PsiWhiteSpace(' ')
                              PsiElement(EQ)('=')
                              PsiWhiteSpace(' ')
                              DOT_QUALIFIED_EXPRESSION
                                REFERENCE_EXPRESSION
                                  PsiElement(IDENTIFIER)('pending')
                                PsiElement(DOT)('.')
                                CALL_EXPRESSION
                                  REFERENCE_EXPRESSION
                                    PsiElement(IDENTIFIER)('pop')
                                  VALUE_ARGUMENT_LIST
                                    PsiElement(LPAR)('(')
                                    PsiElement(RPAR)(')')
                            PsiWhiteSpace('\n        ')
                            CALL_EXPRESSION
                              REFERENCE_EXPRESSION
                                PsiElement(IDENTIFIER)('handler')
                              VALUE_ARGUMENT_LIST
                                PsiElement(LPAR)('(')
                                VALUE_ARGUMENT
                                  REFERENCE_EXPRESSION
                                    PsiElement(IDENTIFIER)('current')
                                PsiElement(RPAR)(')')
                            PsiElement(SEMICOLON)(';')
                            PsiWhiteSpace('\n        ')
                            DOT_QUALIFIED_EXPRESSION
                              CALL_EXPRESSION
                                REFERENCE_EXPRESSION
                                  PsiElement(IDENTIFIER)('neighbours')
                                VALUE_ARGUMENT_LIST
                                  PsiElement(LPAR)('(')
                                  VALUE_ARGUMENT
                                    REFERENCE_EXPRESSION
                                      PsiElement(IDENTIFIER)('current')
                                  PsiElement(RPAR)(')')
                              PsiElement(DOT)('.')
                              CALL_EXPRESSION
                                REFERENCE_EXPRESSION
                                  PsiElement(IDENTIFIER)('foreach')
                                PsiWhiteSpace(' ')
                                FUNCTION_LITERAL_ARGUMENT
                                  FUNCTION_LITERAL_EXPRESSION
                                    FUNCTION_LITERAL
                                      PsiElement(LBRACE)('{')
                                      PsiWhiteSpace(' ')
                                      VALUE_PARAMETER_LIST
                                        VALUE_PARAMETER
                                          PsiElement(IDENTIFIER)('n')
                                      PsiWhiteSpace(' ')
                                      PsiElement(ARROW)('->')
                                      PsiWhiteSpace('\n          ')
                                      BLOCK
                                        IF
                                          PsiElement(if)('if')
                                          PsiWhiteSpace(' ')
                                          PsiElement(LPAR)('(')
                                          CONDITION
                                            DOT_QUALIFIED_EXPRESSION
                                              REFERENCE_EXPRESSION
                                                PsiElement(IDENTIFIER)('visited')
                                              PsiElement(DOT)('.')
                                              CALL_EXPRESSION
                                                REFERENCE_EXPRESSION
                                                  PsiElement(IDENTIFIER)('add')
                                                VALUE_ARGUMENT_LIST
                                                  PsiElement(LPAR)('(')
                                                  VALUE_ARGUMENT
                                                    REFERENCE_EXPRESSION
                                                      PsiElement(IDENTIFIER)('n')
                                                  PsiElement(RPAR)(')')
                                          PsiElement(RPAR)(')')
                                          PsiWhiteSpace(' ')
                                          THEN
                                            BLOCK
                                              PsiElement(LBRACE)('{')
                                              PsiWhiteSpace('\n            ')
                                              DOT_QUALIFIED_EXPRESSION
                                                REFERENCE_EXPRESSION
                                                  PsiElement(IDENTIFIER)('pending')
                                                PsiElement(DOT)('.')
                                                CALL_EXPRESSION
                                                  REFERENCE_EXPRESSION
                                                    PsiElement(IDENTIFIER)('push')
                                                  VALUE_ARGUMENT_LIST
                                                    PsiElement(LPAR)('(')
                                                    VALUE_ARGUMENT
                                                      REFERENCE_EXPRESSION
                                                        PsiElement(IDENTIFIER)('n')
                                                    PsiElement(RPAR)(')')
                                              PsiWhiteSpace('\n          ')
                                              PsiElement(RBRACE)('}')
                                      PsiWhiteSpace('\n        ')
                                      PsiElement(RBRACE)('}')
                            PsiWhiteSpace('\n    ')
                            PsiComment(BLOCK_COMMENT)('/* alternative\n        pending->push(neighbours(current).filter{n => !visited[n])})\n        // -> means that if push(x : T) and actual parameter y is IIterable<T>, this compiles into\n          y.foreach{ n => push(n) }\n     */')
                            PsiWhiteSpace('\n      ')
                            PsiElement(RBRACE)('}')
                    PsiWhiteSpace('\n    ')
                    PsiElement(RBRACE)('}')
          PsiWhiteSpace('\n  ')
          PsiElement(RBRACE)('}')
      PsiWhiteSpace('\n')
      PsiElement(RBRACE)('}')