====== Option +col_sep+

Specifies the \String field separator to be used
for both parsing and generating.
The \String will be transcoded into the data's \Encoding before use.

Default value:
  CSV::DEFAULT_OPTIONS.fetch(:col_sep) # => "," (comma)

Using the default (comma):
  str = CSV.generate do |csv|
    csv << [:foo, 0]
    csv << [:bar, 1]
    csv << [:baz, 2]
  end
  str # => "foo,0\nbar,1\nbaz,2\n"
  ary = CSV.parse(str)
  ary # => [["foo", "0"], ["bar", "1"], ["baz", "2"]]

Using +:+ (colon):
  col_sep = ':'
  str = CSV.generate(col_sep: col_sep) do |csv|
    csv << [:foo, 0]
    csv << [:bar, 1]
    csv << [:baz, 2]
  end
  str # => "foo:0\nbar:1\nbaz:2\n"
  ary = CSV.parse(str, col_sep: col_sep)
  ary # => [["foo", "0"], ["bar", "1"], ["baz", "2"]]

Using +::+ (two colons):
  col_sep = '::'
  str = CSV.generate(col_sep: col_sep) do |csv|
    csv << [:foo, 0]
    csv << [:bar, 1]
    csv << [:baz, 2]
  end
  str # => "foo::0\nbar::1\nbaz::2\n"
  ary = CSV.parse(str, col_sep: col_sep)
  ary # => [["foo", "0"], ["bar", "1"], ["baz", "2"]]

Using <tt>''</tt> (empty string):
  col_sep = ''
  str = CSV.generate(col_sep: col_sep) do |csv|
    csv << [:foo, 0]
    csv << [:bar, 1]
    csv << [:baz, 2]
  end
  str # => "foo0\nbar1\nbaz2\n"

---

Raises an exception if parsing with the empty \String:
  col_sep = ''
  # Raises ArgumentError (:col_sep must be 1 or more characters: "")
  CSV.parse("foo0\nbar1\nbaz2\n", col_sep: col_sep)

Raises an exception if the given value is not String-convertible:
  col_sep = BasicObject.new
  # Raises NoMethodError (undefined method `to_s' for #<BasicObject:>)
  CSV.generate(line, col_sep: col_sep)
  # Raises NoMethodError (undefined method `to_s' for #<BasicObject:>)
  CSV.parse(str, col_sep: col_sep)