Merge csv-1.0.2 from upstream.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@63364 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

6 files changed, 814 insertions, 0 deletions

diff --git a/lib/csv/core_ext/array.rb b/lib/csv/core_ext/array.rb
new file mode 100644
index 0000000000..94df7d5c35
--- /dev/null
+++ b/lib/csv/core_ext/array.rb
@@ -0,0 +1,9 @@
+class Array # :nodoc:
+  # Equivalent to CSV::generate_line(self, options)
+  #
+  #   ["CSV", "data"].to_csv
+  #     #=> "CSV,data\n"
+  def to_csv(**options)
+    CSV.generate_line(self, options)
+  end
+end
diff --git a/lib/csv/core_ext/string.rb b/lib/csv/core_ext/string.rb
new file mode 100644
index 0000000000..8f2070f3bd
--- /dev/null
+++ b/lib/csv/core_ext/string.rb
@@ -0,0 +1,9 @@
+class String # :nodoc:
+  # Equivalent to CSV::parse_line(self, options)
+  #
+  #   "CSV,data".parse_csv
+  #     #=> ["CSV", "data"]
+  def parse_csv(**options)
+    CSV.parse_line(self, options)
+  end
+end
diff --git a/lib/csv/csv.gemspec b/lib/csv/csv.gemspec
new file mode 100644
index 0000000000..38ead7c81d
--- /dev/null
+++ b/lib/csv/csv.gemspec
@@ -0,0 +1,24 @@
+# frozen_string_literal: true
+
+require_relative "lib/csv/version"
+
+Gem::Specification.new do |spec|
+  spec.name          = "csv"
+  spec.version       = CSV::VERSION
+  spec.authors       = ["James Edward Gray II", "Kouhei Sutou"]
+  spec.email         = [nil, "kou@cozmixng.org"]
+
+  spec.summary       = "CSV Reading and Writing"
+  spec.description   = "The CSV library provides a complete interface to CSV files and data. It offers tools to enable you to read and write to and from Strings or IO objects, as needed."
+  spec.homepage      = "https://github.com/ruby/csv"
+  spec.license       = "BSD-2-Clause"
+
+  spec.files         = Dir.glob("lib/**/*.rb")
+  spec.files         += ["README.md", "LICENSE.txt", "news.md"]
+  spec.require_paths = ["lib"]
+  spec.required_ruby_version = ">= 2.3.0"
+
+  spec.add_development_dependency "bundler"
+  spec.add_development_dependency "rake"
+  spec.add_development_dependency "benchmark-ips"
+end
diff --git a/lib/csv/row.rb b/lib/csv/row.rb
new file mode 100644
index 0000000000..8ff3480ae8
--- /dev/null
+++ b/lib/csv/row.rb
@@ -0,0 +1,388 @@
+# frozen_string_literal: true
+
+require "forwardable"
+
+class CSV
+  #
+  # A CSV::Row is part Array and part Hash.  It retains an order for the fields
+  # and allows duplicates just as an Array would, but also allows you to access
+  # fields by name just as you could if they were in a Hash.
+  #
+  # All rows returned by CSV will be constructed from this class, if header row
+  # processing is activated.
+  #
+  class Row
+    #
+    # Construct a new CSV::Row from +headers+ and +fields+, which are expected
+    # to be Arrays.  If one Array is shorter than the other, it will be padded
+    # with +nil+ objects.
+    #
+    # The optional +header_row+ parameter can be set to +true+ to indicate, via
+    # CSV::Row.header_row?() and CSV::Row.field_row?(), that this is a header
+    # row.  Otherwise, the row is assumes to be a field row.
+    #
+    # A CSV::Row object supports the following Array methods through delegation:
+    #
+    # * empty?()
+    # * length()
+    # * size()
+    #
+    def initialize(headers, fields, header_row = false)
+      @header_row = header_row
+      headers.each { |h| h.freeze if h.is_a? String }
+
+      # handle extra headers or fields
+      @row = if headers.size >= fields.size
+        headers.zip(fields)
+      else
+        fields.zip(headers).each(&:reverse!)
+      end
+    end
+
+    # Internal data format used to compare equality.
+    attr_reader :row
+    protected   :row
+
+    ### Array Delegation ###
+
+    extend Forwardable
+    def_delegators :@row, :empty?, :length, :size
+
+    # Returns +true+ if this is a header row.
+    def header_row?
+      @header_row
+    end
+
+    # Returns +true+ if this is a field row.
+    def field_row?
+      not header_row?
+    end
+
+    # Returns the headers of this row.
+    def headers
+      @row.map(&:first)
+    end
+
+    #
+    # :call-seq:
+    #   field( header )
+    #   field( header, offset )
+    #   field( index )
+    #
+    # This method will return the field value by +header+ or +index+.  If a field
+    # is not found, +nil+ is returned.
+    #
+    # When provided, +offset+ ensures that a header match occurs on or later
+    # than the +offset+ index.  You can use this to find duplicate headers,
+    # without resorting to hard-coding exact indices.
+    #
+    def field(header_or_index, minimum_index = 0)
+      # locate the pair
+      finder = (header_or_index.is_a?(Integer) || header_or_index.is_a?(Range)) ? :[] : :assoc
+      pair   = @row[minimum_index..-1].send(finder, header_or_index)
+
+      # return the field if we have a pair
+      if pair.nil?
+        nil
+      else
+        header_or_index.is_a?(Range) ? pair.map(&:last) : pair.last
+      end
+    end
+    alias_method :[], :field
+
+    #
+    # :call-seq:
+    #   fetch( header )
+    #   fetch( header ) { |row| ... }
+    #   fetch( header, default )
+    #
+    # This method will fetch the field value by +header+. It has the same
+    # behavior as Hash#fetch: if there is a field with the given +header+, its
+    # value is returned. Otherwise, if a block is given, it is yielded the
+    # +header+ and its result is returned; if a +default+ is given as the
+    # second argument, it is returned; otherwise a KeyError is raised.
+    #
+    def fetch(header, *varargs)
+      raise ArgumentError, "Too many arguments" if varargs.length > 1
+      pair = @row.assoc(header)
+      if pair
+        pair.last
+      else
+        if block_given?
+          yield header
+        elsif varargs.empty?
+          raise KeyError, "key not found: #{header}"
+        else
+          varargs.first
+        end
+      end
+    end
+
+    # Returns +true+ if there is a field with the given +header+.
+    def has_key?(header)
+      !!@row.assoc(header)
+    end
+    alias_method :include?, :has_key?
+    alias_method :key?,     :has_key?
+    alias_method :member?,  :has_key?
+
+    #
+    # :call-seq:
+    #   []=( header, value )
+    #   []=( header, offset, value )
+    #   []=( index, value )
+    #
+    # Looks up the field by the semantics described in CSV::Row.field() and
+    # assigns the +value+.
+    #
+    # Assigning past the end of the row with an index will set all pairs between
+    # to <tt>[nil, nil]</tt>.  Assigning to an unused header appends the new
+    # pair.
+    #
+    def []=(*args)
+      value = args.pop
+
+      if args.first.is_a? Integer
+        if @row[args.first].nil?  # extending past the end with index
+          @row[args.first] = [nil, value]
+          @row.map! { |pair| pair.nil? ? [nil, nil] : pair }
+        else                      # normal index assignment
+          @row[args.first][1] = value
+        end
+      else
+        index = index(*args)
+        if index.nil?             # appending a field
+          self << [args.first, value]
+        else                      # normal header assignment
+          @row[index][1] = value
+        end
+      end
+    end
+
+    #
+    # :call-seq:
+    #   <<( field )
+    #   <<( header_and_field_array )
+    #   <<( header_and_field_hash )
+    #
+    # If a two-element Array is provided, it is assumed to be a header and field
+    # and the pair is appended.  A Hash works the same way with the key being
+    # the header and the value being the field.  Anything else is assumed to be
+    # a lone field which is appended with a +nil+ header.
+    #
+    # This method returns the row for chaining.
+    #
+    def <<(arg)
+      if arg.is_a?(Array) and arg.size == 2  # appending a header and name
+        @row << arg
+      elsif arg.is_a?(Hash)                  # append header and name pairs
+        arg.each { |pair| @row << pair }
+      else                                   # append field value
+        @row << [nil, arg]
+      end
+
+      self  # for chaining
+    end
+
+    #
+    # A shortcut for appending multiple fields.  Equivalent to:
+    #
+    #   args.each { |arg| csv_row << arg }
+    #
+    # This method returns the row for chaining.
+    #
+    def push(*args)
+      args.each { |arg| self << arg }
+
+      self  # for chaining
+    end
+
+    #
+    # :call-seq:
+    #   delete( header )
+    #   delete( header, offset )
+    #   delete( index )
+    #
+    # Used to remove a pair from the row by +header+ or +index+.  The pair is
+    # located as described in CSV::Row.field().  The deleted pair is returned,
+    # or +nil+ if a pair could not be found.
+    #
+    def delete(header_or_index, minimum_index = 0)
+      if header_or_index.is_a? Integer                 # by index
+        @row.delete_at(header_or_index)
+      elsif i = index(header_or_index, minimum_index)  # by header
+        @row.delete_at(i)
+      else
+        [ ]
+      end
+    end
+
+    #
+    # The provided +block+ is passed a header and field for each pair in the row
+    # and expected to return +true+ or +false+, depending on whether the pair
+    # should be deleted.
+    #
+    # This method returns the row for chaining.
+    #
+    # If no block is given, an Enumerator is returned.
+    #
+    def delete_if(&block)
+      return enum_for(__method__) { size } unless block_given?
+
+      @row.delete_if(&block)
+
+      self  # for chaining
+    end
+
+    #
+    # This method accepts any number of arguments which can be headers, indices,
+    # Ranges of either, or two-element Arrays containing a header and offset.
+    # Each argument will be replaced with a field lookup as described in
+    # CSV::Row.field().
+    #
+    # If called with no arguments, all fields are returned.
+    #
+    def fields(*headers_and_or_indices)
+      if headers_and_or_indices.empty?  # return all fields--no arguments
+        @row.map(&:last)
+      else                              # or work like values_at()
+        all = []
+        headers_and_or_indices.each do |h_or_i|
+          if h_or_i.is_a? Range
+            index_begin = h_or_i.begin.is_a?(Integer) ? h_or_i.begin :
+                                                        index(h_or_i.begin)
+            index_end   = h_or_i.end.is_a?(Integer)   ? h_or_i.end :
+                                                        index(h_or_i.end)
+            new_range   = h_or_i.exclude_end? ? (index_begin...index_end) :
+                                                (index_begin..index_end)
+            all.concat(fields.values_at(new_range))
+          else
+            all << field(*Array(h_or_i))
+          end
+        end
+        return all
+      end
+    end
+    alias_method :values_at, :fields
+
+    #
+    # :call-seq:
+    #   index( header )
+    #   index( header, offset )
+    #
+    # This method will return the index of a field with the provided +header+.
+    # The +offset+ can be used to locate duplicate header names, as described in
+    # CSV::Row.field().
+    #
+    def index(header, minimum_index = 0)
+      # find the pair
+      index = headers[minimum_index..-1].index(header)
+      # return the index at the right offset, if we found one
+      index.nil? ? nil : index + minimum_index
+    end
+
+    # Returns +true+ if +name+ is a header for this row, and +false+ otherwise.
+    def header?(name)
+      headers.include? name
+    end
+    alias_method :include?, :header?
+
+    #
+    # Returns +true+ if +data+ matches a field in this row, and +false+
+    # otherwise.
+    #
+    def field?(data)
+      fields.include? data
+    end
+
+    include Enumerable
+
+    #
+    # Yields each pair of the row as header and field tuples (much like
+    # iterating over a Hash). This method returns the row for chaining.
+    #
+    # If no block is given, an Enumerator is returned.
+    #
+    # Support for Enumerable.
+    #
+    def each(&block)
+      return enum_for(__method__) { size } unless block_given?
+
+      @row.each(&block)
+
+      self  # for chaining
+    end
+
+    alias_method :each_pair, :each
+
+    #
+    # Returns +true+ if this row contains the same headers and fields in the
+    # same order as +other+.
+    #
+    def ==(other)
+      return @row == other.row if other.is_a? CSV::Row
+      @row == other
+    end
+
+    #
+    # Collapses the row into a simple Hash.  Be warned that this discards field
+    # order and clobbers duplicate fields.
+    #
+    def to_h
+      hash = {}
+      each do |key, _value|
+        hash[key] = self[key] unless hash.key?(key)
+      end
+      hash
+    end
+    alias_method :to_hash, :to_h
+
+    alias_method :to_ary, :to_a
+
+    #
+    # Returns the row as a CSV String.  Headers are not used.  Equivalent to:
+    #
+    #   csv_row.fields.to_csv( options )
+    #
+    def to_csv(**options)
+      fields.to_csv(options)
+    end
+    alias_method :to_s, :to_csv
+
+    #
+    # Extracts the nested value specified by the sequence of +index+ or +header+ objects by calling dig at each step,
+    # returning nil if any intermediate step is nil.
+    #
+    def dig(index_or_header, *indexes)
+      value = field(index_or_header)
+      if value.nil?
+        nil
+      elsif indexes.empty?
+        value
+      else
+        unless value.respond_to?(:dig)
+          raise TypeError, "#{value.class} does not have \#dig method"
+        end
+        value.dig(*indexes)
+      end
+    end
+
+    # A summary of fields, by header, in an ASCII compatible String.
+    def inspect
+      str = ["#<", self.class.to_s]
+      each do |header, field|
+        str << " " << (header.is_a?(Symbol) ? header.to_s : header.inspect) <<
+               ":" << field.inspect
+      end
+      str << ">"
+      begin
+        str.join('')
+      rescue  # any encoding error
+        str.map do |s|
+          e = Encoding::Converter.asciicompat_encoding(s.encoding)
+          e ? s.encode(e) : s.force_encoding("ASCII-8BIT")
+        end.join('')
+      end
+    end
+  end
+end
diff --git a/lib/csv/table.rb b/lib/csv/table.rb
new file mode 100644
index 0000000000..e9f3366a4a
--- /dev/null
+++ b/lib/csv/table.rb
@@ -0,0 +1,378 @@
+# frozen_string_literal: true
+
+require "forwardable"
+
+class CSV
+  #
+  # A CSV::Table is a two-dimensional data structure for representing CSV
+  # documents.  Tables allow you to work with the data by row or column,
+  # manipulate the data, and even convert the results back to CSV, if needed.
+  #
+  # All tables returned by CSV will be constructed from this class, if header
+  # row processing is activated.
+  #
+  class Table
+    #
+    # Construct a new CSV::Table from +array_of_rows+, which are expected
+    # to be CSV::Row objects.  All rows are assumed to have the same headers.
+    #
+    # A CSV::Table object supports the following Array methods through
+    # delegation:
+    #
+    # * empty?()
+    # * length()
+    # * size()
+    #
+    def initialize(array_of_rows)
+      @table = array_of_rows
+      @mode  = :col_or_row
+    end
+
+    # The current access mode for indexing and iteration.
+    attr_reader :mode
+
+    # Internal data format used to compare equality.
+    attr_reader :table
+    protected   :table
+
+    ### Array Delegation ###
+
+    extend Forwardable
+    def_delegators :@table, :empty?, :length, :size
+
+    #
+    # Returns a duplicate table object, in column mode.  This is handy for
+    # chaining in a single call without changing the table mode, but be aware
+    # that this method can consume a fair amount of memory for bigger data sets.
+    #
+    # This method returns the duplicate table for chaining.  Don't chain
+    # destructive methods (like []=()) this way though, since you are working
+    # with a duplicate.
+    #
+    def by_col
+      self.class.new(@table.dup).by_col!
+    end
+
+    #
+    # Switches the mode of this table to column mode.  All calls to indexing and
+    # iteration methods will work with columns until the mode is changed again.
+    #
+    # This method returns the table and is safe to chain.
+    #
+    def by_col!
+      @mode = :col
+
+      self
+    end
+
+    #
+    # Returns a duplicate table object, in mixed mode.  This is handy for
+    # chaining in a single call without changing the table mode, but be aware
+    # that this method can consume a fair amount of memory for bigger data sets.
+    #
+    # This method returns the duplicate table for chaining.  Don't chain
+    # destructive methods (like []=()) this way though, since you are working
+    # with a duplicate.
+    #
+    def by_col_or_row
+      self.class.new(@table.dup).by_col_or_row!
+    end
+
+    #
+    # Switches the mode of this table to mixed mode.  All calls to indexing and
+    # iteration methods will use the default intelligent indexing system until
+    # the mode is changed again.  In mixed mode an index is assumed to be a row
+    # reference while anything else is assumed to be column access by headers.
+    #
+    # This method returns the table and is safe to chain.
+    #
+    def by_col_or_row!
+      @mode = :col_or_row
+
+      self
+    end
+
+    #
+    # Returns a duplicate table object, in row mode.  This is handy for chaining
+    # in a single call without changing the table mode, but be aware that this
+    # method can consume a fair amount of memory for bigger data sets.
+    #
+    # This method returns the duplicate table for chaining.  Don't chain
+    # destructive methods (like []=()) this way though, since you are working
+    # with a duplicate.
+    #
+    def by_row
+      self.class.new(@table.dup).by_row!
+    end
+
+    #
+    # Switches the mode of this table to row mode.  All calls to indexing and
+    # iteration methods will work with rows until the mode is changed again.
+    #
+    # This method returns the table and is safe to chain.
+    #
+    def by_row!
+      @mode = :row
+
+      self
+    end
+
+    #
+    # Returns the headers for the first row of this table (assumed to match all
+    # other rows).  An empty Array is returned for empty tables.
+    #
+    def headers
+      if @table.empty?
+        Array.new
+      else
+        @table.first.headers
+      end
+    end
+
+    #
+    # In the default mixed mode, this method returns rows for index access and
+    # columns for header access.  You can force the index association by first
+    # calling by_col!() or by_row!().
+    #
+    # Columns are returned as an Array of values.  Altering that Array has no
+    # effect on the table.
+    #
+    def [](index_or_header)
+      if @mode == :row or  # by index
+         (@mode == :col_or_row and (index_or_header.is_a?(Integer) or index_or_header.is_a?(Range)))
+        @table[index_or_header]
+      else                 # by header
+        @table.map { |row| row[index_or_header] }
+      end
+    end
+
+    #
+    # In the default mixed mode, this method assigns rows for index access and
+    # columns for header access.  You can force the index association by first
+    # calling by_col!() or by_row!().
+    #
+    # Rows may be set to an Array of values (which will inherit the table's
+    # headers()) or a CSV::Row.
+    #
+    # Columns may be set to a single value, which is copied to each row of the
+    # column, or an Array of values.  Arrays of values are assigned to rows top
+    # to bottom in row major order.  Excess values are ignored and if the Array
+    # does not have a value for each row the extra rows will receive a +nil+.
+    #
+    # Assigning to an existing column or row clobbers the data.  Assigning to
+    # new columns creates them at the right end of the table.
+    #
+    def []=(index_or_header, value)
+      if @mode == :row or  # by index
+         (@mode == :col_or_row and index_or_header.is_a? Integer)
+        if value.is_a? Array
+          @table[index_or_header] = Row.new(headers, value)
+        else
+          @table[index_or_header] = value
+        end
+      else                 # set column
+        if value.is_a? Array  # multiple values
+          @table.each_with_index do |row, i|
+            if row.header_row?
+              row[index_or_header] = index_or_header
+            else
+              row[index_or_header] = value[i]
+            end
+          end
+        else                  # repeated value
+          @table.each do |row|
+            if row.header_row?
+              row[index_or_header] = index_or_header
+            else
+              row[index_or_header] = value
+            end
+          end
+        end
+      end
+    end
+
+    #
+    # The mixed mode default is to treat a list of indices as row access,
+    # returning the rows indicated.  Anything else is considered columnar
+    # access.  For columnar access, the return set has an Array for each row
+    # with the values indicated by the headers in each Array.  You can force
+    # column or row mode using by_col!() or by_row!().
+    #
+    # You cannot mix column and row access.
+    #
+    def values_at(*indices_or_headers)
+      if @mode == :row or  # by indices
+         ( @mode == :col_or_row and indices_or_headers.all? do |index|
+                                      index.is_a?(Integer)         or
+                                      ( index.is_a?(Range)         and
+                                        index.first.is_a?(Integer) and
+                                        index.last.is_a?(Integer) )
+                                    end )
+        @table.values_at(*indices_or_headers)
+      else                 # by headers
+        @table.map { |row| row.values_at(*indices_or_headers) }
+      end
+    end
+
+    #
+    # Adds a new row to the bottom end of this table.  You can provide an Array,
+    # which will be converted to a CSV::Row (inheriting the table's headers()),
+    # or a CSV::Row.
+    #
+    # This method returns the table for chaining.
+    #
+    def <<(row_or_array)
+      if row_or_array.is_a? Array  # append Array
+        @table << Row.new(headers, row_or_array)
+      else                         # append Row
+        @table << row_or_array
+      end
+
+      self # for chaining
+    end
+
+    #
+    # A shortcut for appending multiple rows.  Equivalent to:
+    #
+    #   rows.each { |row| self << row }
+    #
+    # This method returns the table for chaining.
+    #
+    def push(*rows)
+      rows.each { |row| self << row }
+
+      self # for chaining
+    end
+
+    #
+    # Removes and returns the indicated columns or rows.  In the default mixed
+    # mode indices refer to rows and everything else is assumed to be a column
+    # headers.  Use by_col!() or by_row!() to force the lookup.
+    #
+    def delete(*indexes_or_headers)
+      if indexes_or_headers.empty?
+        raise ArgumentError, "wrong number of arguments (given 0, expected 1+)"
+      end
+      deleted_values = indexes_or_headers.map do |index_or_header|
+        if @mode == :row or  # by index
+            (@mode == :col_or_row and index_or_header.is_a? Integer)
+          @table.delete_at(index_or_header)
+        else                 # by header
+          @table.map { |row| row.delete(index_or_header).last }
+        end
+      end
+      if indexes_or_headers.size == 1
+        deleted_values[0]
+      else
+        deleted_values
+      end
+    end
+
+    #
+    # Removes any column or row for which the block returns +true+.  In the
+    # default mixed mode or row mode, iteration is the standard row major
+    # walking of rows.  In column mode, iteration will +yield+ two element
+    # tuples containing the column name and an Array of values for that column.
+    #
+    # This method returns the table for chaining.
+    #
+    # If no block is given, an Enumerator is returned.
+    #
+    def delete_if(&block)
+      return enum_for(__method__) { @mode == :row or @mode == :col_or_row ? size : headers.size } unless block_given?
+
+      if @mode == :row or @mode == :col_or_row  # by index
+        @table.delete_if(&block)
+      else                                      # by header
+        deleted = []
+        headers.each do |header|
+          deleted << delete(header) if yield([header, self[header]])
+        end
+      end
+
+      self # for chaining
+    end
+
+    include Enumerable
+
+    #
+    # In the default mixed mode or row mode, iteration is the standard row major
+    # walking of rows.  In column mode, iteration will +yield+ two element
+    # tuples containing the column name and an Array of values for that column.
+    #
+    # This method returns the table for chaining.
+    #
+    # If no block is given, an Enumerator is returned.
+    #
+    def each(&block)
+      return enum_for(__method__) { @mode == :col ? headers.size : size } unless block_given?
+
+      if @mode == :col
+        headers.each { |header| yield([header, self[header]]) }
+      else
+        @table.each(&block)
+      end
+
+      self # for chaining
+    end
+
+    # Returns +true+ if all rows of this table ==() +other+'s rows.
+    def ==(other)
+      return @table == other.table if other.is_a? CSV::Table
+      @table == other
+    end
+
+    #
+    # Returns the table as an Array of Arrays.  Headers will be the first row,
+    # then all of the field rows will follow.
+    #
+    def to_a
+      array = [headers]
+      @table.each do |row|
+        array.push(row.fields) unless row.header_row?
+      end
+
+      array
+    end
+
+    #
+    # Returns the table as a complete CSV String.  Headers will be listed first,
+    # then all of the field rows.
+    #
+    # This method assumes you want the Table.headers(), unless you explicitly
+    # pass <tt>:write_headers => false</tt>.
+    #
+    def to_csv(write_headers: true, **options)
+      array = write_headers ? [headers.to_csv(options)] : []
+      @table.each do |row|
+        array.push(row.fields.to_csv(options)) unless row.header_row?
+      end
+
+      array.join("")
+    end
+    alias_method :to_s, :to_csv
+
+    #
+    # Extracts the nested value specified by the sequence of +index+ or +header+ objects by calling dig at each step,
+    # returning nil if any intermediate step is nil.
+    #
+    def dig(index_or_header, *index_or_headers)
+      value = self[index_or_header]
+      if value.nil?
+        nil
+      elsif index_or_headers.empty?
+        value
+      else
+        unless value.respond_to?(:dig)
+          raise TypeError, "#{value.class} does not have \#dig method"
+        end
+        value.dig(*index_or_headers)
+      end
+    end
+
+    # Shows the mode and size of this table in a US-ASCII String.
+    def inspect
+      "#<#{self.class} mode:#{@mode} row_count:#{to_a.size}>".encode("US-ASCII")
+    end
+  end
+end
\ No newline at end of file
diff --git a/lib/csv/version.rb b/lib/csv/version.rb
new file mode 100644
index 0000000000..35adea3a92
--- /dev/null
+++ b/lib/csv/version.rb
@@ -0,0 +1,6 @@
+# frozen_string_literal: true
+
+class CSV
+  # The version of the installed library.
+  VERSION = "1.0.2"
+end