JetFile: Graph.jet
  NAMESPACE
    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_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_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
                  PsiElement(fun)('fun')
                  PsiWhiteSpace(' ')
                  VALUE_PARAMETER_LIST
                    PsiElement(LPAR)('(')
                    VALUE_PARAMETER
                      TYPE_REFERENCE
                        USER_TYPE
                          REFERENCE_EXPRESSION
                            PsiElement(IDENTIFIER)('V')
                    PsiElement(RPAR)(')')
                  PsiWhiteSpace(' ')
                  PsiElement(COLON)(':')
                  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_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
                      PsiElement(fun)('fun')
                      PsiWhiteSpace(' ')
                      VALUE_PARAMETER_LIST
                        PsiElement(LPAR)('(')
                        VALUE_PARAMETER
                          TYPE_REFERENCE
                            USER_TYPE
                              REFERENCE_EXPRESSION
                                PsiElement(IDENTIFIER)('V')
                        PsiElement(RPAR)(')')
                      PsiWhiteSpace(' ')
                      PsiElement(COLON)(':')
                      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_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
                  PsiElement(fun)('fun')
                  PsiWhiteSpace(' ')
                  VALUE_PARAMETER_LIST
                    PsiElement(LPAR)('(')
                    VALUE_PARAMETER
                      TYPE_REFERENCE
                        USER_TYPE
                          REFERENCE_EXPRESSION
                            PsiElement(IDENTIFIER)('V')
                    PsiElement(RPAR)(')')
                  PsiWhiteSpace(' ')
                  PsiElement(COLON)(':')
                  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_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_EXPRESSION
                                  FUNCTION_LITERAL
                                    PsiElement(LBRACE)('{')
                                    PsiWhiteSpace(' ')
                                    VALUE_PARAMETER_LIST
                                      VALUE_PARAMETER
                                        PsiElement(IDENTIFIER)('n')
                                    PsiWhiteSpace(' ')
                                    PsiElement(DOUBLE_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)('}')