@!visibility private (see DependencyGraph#add_edge_no_circular)
@!visibility private @see DependencyGraph#detach_vertex_named
Pushes the current directory to the directory stack, changing the current directory to path.
If path is omitted, it exchanges its current directory and the top of its directory stack.
If a block is given, it restores the current directory when the block ends.
Returns the real (absolute) pathname of pathname in the actual filesystem. The real pathname doesn’t contain symlinks or useless dots.
If dir_string is given, it is used as a base directory for interpreting relative pathname instead of the current directory.
The last component of the real pathname can be nonexistent.
Returns all components of the filename given in file_name except the last one (after first stripping trailing separators). The filename can be formed using both File::SEPARATOR and File::ALT_SEPARATOR as the separator when File::ALT_SEPARATOR is not nil.
File.dirname("/home/gumby/work/ruby.rb") #=> "/home/gumby/work"
Returns true if the named file is a directory, or a symlink that points at a directory, and false otherwise.
file_name can be an IO object.
File.directory?(".")
Returns the real (absolute) pathname of self in the actual filesystem.
Does not contain symlinks or useless dots, .. and ..
The last component of the real pathname can be nonexistent.
Pops a directory from the directory stack, and sets the current directory to it.
Returns system configuration directory.
This is typically “/etc”, but is modified by the prefix used when Ruby was compiled. For example, if Ruby is built and installed in /usr/local, returns “/usr/local/etc” on other platforms than Windows. On Windows, this always returns the directory provided by the system.
Returns system temporary directory; typically “/tmp”.
Returns true if the named file is a directory, or a symlink that points at a directory, and false otherwise.
file_name can be an IO object.
File.directory?(".")
The path where gem executables are to be installed.
The path to the data directory specified by the gem name. If the package is not available as a gem, return nil.