Split slashes in paths, but not URLs

split_path_slashes_but_not_url_slashes.rb

def split_path(path)
  slash = Regexp.escape File::SEPARATOR
  match = path.match(%r~       # regex that is delimited by tildes so I can use slashes, quotes, backticks, etc in the comments
    (                          # capture whatever the path_slash group matches
      (?<path_slash>           # a named group that matches slashes in paths, but not urls, eg will not match "http://example.com"
        # don't match first slash in "://"
        (?:                    # don't capture this group
          (?<!:)               # not preceeded by ":"
          (?!#{slash}#{slash}) # not succeeded by "//" (we haven't matched the slash yet, so it's in front of the cursor)
        )
        # don't match second slash in "://"
        (?<!:#{slash})         # not preceeded by ":/"
        # match any number of slashes eg `File.split "a//b" # => ["a", "b"]`
        (?:#{slash})+          # but don't capture them
      )
    )
    (?=                        # make sure it's the last path slash (no more after it)
      (?:                      # don't capture this group
        (?!\g<path_slash>)     # there is not a path slash in after the cursor
        .                      # consume the next character
      )*                       # 0 or more of these (eg can be the last thing in the string)
      \z                       # and then the string ends
    )
  ~xo)                         # x ignores whitespace and comments, o means it will onlly build the regex the first time it's evaluated              
  if !match
    [".", path]                         # File.split "" # => [".", ""]
  elsif match.pre_match.empty? && match.post_match.empty?
    [slash, slash]                      # File.split "/" # => ["/", "/"]
  elsif match.pre_match.empty?
    [slash, match.post_match]           # File.split "/a" # => ["/", "a"]
  elsif match.post_match.empty?
    split_path(match.pre_match)         # File.split "a/b/" # => ["a", "b"]
  else
    [match.pre_match, match.post_match] # File.split "a/b" # => ["a", "b"]
  end
end

def components_of(path)
  dirname, basename = split_path path
  return [basename] if basename == path
  components_of(dirname) << basename
end

components_of "/a/b/c.rb"
# => ["/", "a", "b", "c.rb"]

components_of "./a/b//c.rb"
# => [".", "a", "b", "c.rb"]

components_of "http://example.com/some/path"
# => ["http://example.com", "some", "path"]

components_of "path/to////test/namespace_with_the_url_http://url1.com_in_it/test_with_url_http://url2.com_in_it"
# => ["path",
#     "to",
#     "test",
#     "namespace_with_the_url_http://url1.com_in_it",
#     "test_with_url_http://url2.com_in_it"]