Transfer control to another fiber, resuming it from where it last stopped or starting it if it was not resumed before. The calling fiber will be suspended much like in a call to Fiber.yield. You need to require 'fiber' before using this method.
The fiber which receives the transfer call is treats it much like a resume call. Arguments passed to transfer are treated like those passed to resume.
The two style of control passing to and from fiber (one is resume and Fiber::yield, another is transfer to and from fiber) can’t be freely mixed.
If the Fiber’s lifecycle had started with transfer, it will never be able to yield or be resumed control passing, only finish or transfer back. (It still can resume other fibers that are allowed to be resumed.)
If the Fiber’s lifecycle had started with resume, it can yield or transfer to another Fiber, but can receive control back only the way compatible with the way it was given away: if it had transferred, it only can be transferred back, and if it had yielded, it only can be resumed back. After that, it again can transfer or yield.
If those rules are broken FiberError is raised.
For an individual Fiber design, yield/resume is more easy to use style (the Fiber just gives away control, it doesn’t need to think about who the control is given to), while transfer is more flexible for complex cases, allowing to build arbitrary graphs of Fibers dependent on each other.
Example:
require 'fiber' manager = nil # For local var to be visible inside worker block # This fiber would be started with transfer # It can't yield, and can't be resumed worker = Fiber.new { |work| puts "Worker: starts" puts "Worker: Performed #{work.inspect}, transferring back" # Fiber.yield # this would raise FiberError: attempt to yield on a not resumed fiber # manager.resume # this would raise FiberError: attempt to resume a resumed fiber (double resume) manager.transfer(work.capitalize) } # This fiber would be started with resume # It can yield or transfer, and can be transferred # back or resumed manager = Fiber.new { puts "Manager: starts" puts "Manager: transferring 'something' to worker" result = worker.transfer('something') puts "Manager: worker returned #{result.inspect}" # worker.resume # this would raise FiberError: attempt to resume a transferring fiber Fiber.yield # this is OK, the fiber transferred from and to, now it can yield puts "Manager: finished" } puts "Starting the manager" manager.resume puts "Resuming the manager" # manager.transfer # this would raise FiberError: attempt to transfer to a yielding fiber manager.resume
produces
Starting the manager Manager: starts Manager: transferring 'something' to worker Worker: starts Worker: Performed "something", transferring back Manager: worker returned "Something" Resuming the manager Manager: finished
Closes the directory stream. Calling this method on closed Dir object is ignored since Ruby 2.3.
d = Dir.new("testdir") d.close #=> nil
Returns the path to the current working directory of this process as a string.
Dir.chdir("/tmp") #=> 0 Dir.getwd #=> "/tmp" Dir.pwd #=> "/tmp"
Dir.glob( pattern, [flags], [base: path] [, sort: true] ) -> array
Dir.glob( pattern, [flags], [base: path] [, sort: true] ) { |filename| block } -> nil
Expands pattern, which is a pattern string or an Array of pattern strings, and returns an array containing the matching filenames. If a block is given, calls the block once for each matching filename, passing the filename as a parameter to the block.
The optional base keyword argument specifies the base directory for interpreting relative pathnames instead of the current working directory. As the results are not prefixed with the base directory name in this case, you will need to prepend the base directory name if you want real paths.
The results which matched single wildcard or character set are sorted in binary ascending order, unless false is given as the optional sort keyword argument. The order of an Array of pattern strings and braces are preserved.
Note that the pattern is not a regexp, it’s closer to a shell glob. See File::fnmatch for the meaning of the flags parameter. Case sensitivity depends on your system (File::FNM_CASEFOLD is ignored).
*
Matches any file. Can be restricted by other values in the glob. Equivalent to / .* /mx in regexp.
*
Matches all files
c*
Matches all files beginning with c
*c
Matches all files ending with c
*c*
Match all files that have c in them (including at the beginning or end).
Note, this will not match Unix-like hidden files (dotfiles). In order to include those in the match results, you must use the File::FNM_DOTMATCH flag or something like "{*,.*}".
**
Matches directories recursively if followed by /. If this path segment contains any other characters, it is the same as the usual *.
?
Matches any one character. Equivalent to /.{1}/ in regexp.
[set]
Matches any one character in set. Behaves exactly like character sets in Regexp, including set negation ([^a-z]).
{p,q}
Matches either literal p or literal q. Equivalent to pattern alternation in regexp.
Matching literals may be more than one character in length. More than two literals may be specified.
\
Escapes the next metacharacter.
Note that this means you cannot use backslash on windows as part of a glob, i.e. Dir["c:\foo*"] will not work, use Dir["c:/foo*"] instead.
Examples:
Dir["config.?"] #=> ["config.h"] Dir.glob("config.?") #=> ["config.h"] Dir.glob("*.[a-z][a-z]") #=> ["main.rb"] Dir.glob("*.[^r]*") #=> ["config.h"] Dir.glob("*.{rb,h}") #=> ["main.rb", "config.h"] Dir.glob("*") #=> ["config.h", "main.rb"] Dir.glob("*", File::FNM_DOTMATCH) #=> [".", "..", "config.h", "main.rb"] Dir.glob(["*.rb", "*.h"]) #=> ["main.rb", "config.h"] Dir.glob("**/*.rb") #=> ["main.rb", # "lib/song.rb", # "lib/song/karaoke.rb"] Dir.glob("**/*.rb", base: "lib") #=> ["song.rb", # "song/karaoke.rb"] Dir.glob("**/lib") #=> ["lib"] Dir.glob("**/lib/**/*.rb") #=> ["lib/song.rb", # "lib/song/karaoke.rb"] Dir.glob("**/lib/*.rb") #=> ["lib/song.rb"]
Locks or unlocks a file according to locking_constant (a logical or of the values in the table below). Returns false if File::LOCK_NB is specified and the operation would otherwise have blocked. Not available on all platforms.
Locking constants (in class File):
LOCK_EX | Exclusive lock. Only one process may hold an
| exclusive lock for a given file at a time.
----------+------------------------------------------------
LOCK_NB | Don't block when locking. May be combined
| with other lock options using logical or.
----------+------------------------------------------------
LOCK_SH | Shared lock. Multiple processes may each hold a
| shared lock for a given file at the same time.
----------+------------------------------------------------
LOCK_UN | Unlock.
Example:
# update a counter using write lock # don't use "w" because it truncates the file before lock. File.open("counter", File::RDWR|File::CREAT, 0644) {|f| f.flock(File::LOCK_EX) value = f.read.to_i + 1 f.rewind f.write("#{value}\n") f.flush f.truncate(f.pos) } # read the counter using read lock File.open("counter", "r") {|f| f.flock(File::LOCK_SH) p f.read }
Returns true if the named file exists and has a zero size.
file_name can be an IO object.
Returns the result of invoking exception.to_s. Normally this returns the exception’s message or name.
Return the receiver associated with this KeyError exception.
Return the receiver associated with this NameError exception.
Return the receiver associated with this FrozenError exception.
Return this SystemCallError’s error number.
Registers filename to be loaded (using Kernel::require) the first time that module (which may be a String or a symbol) is accessed in the namespace of mod.
module A end A.autoload(:B, "b") A::B.doit # autoloads "b"
Returns filename to be loaded if name is registered as autoload in the namespace of mod or one of its ancestors.
module A end A.autoload(:B, "b") A.autoload?(:B) #=> "b"
If inherit is false, the lookup only checks the autoloads in the receiver:
class A autoload :CONST, "const.rb" end class B < A end B.autoload?(:CONST) #=> "const.rb", found in A (ancestor) B.autoload?(:CONST, false) #=> nil, not found in B itself
Internal method used to provide marshalling support. See the Marshal module.
Returns the remainder from dividing by the value.
x.remainder(y) means x-y*(x/y).truncate
Return the largest integer less than or equal to the value, as a BigDecimal.
BigDecimal('3.14159').floor #=> 3 BigDecimal('-9.1').floor #=> -10
If n is specified and positive, the fractional part of the result has no more than that many digits.
If n is specified and negative, at least that many digits to the left of the decimal point will be 0 in the result.
BigDecimal('3.14159').floor(3) #=> 3.141 BigDecimal('13345.234').floor(-2) #=> 13300.0
Returns the value raised to the power of n.
Note that n must be an Integer.
Also available as the operator **.
Returns True if the value is zero.
Returns self if the value is non-zero, nil otherwise.
The coerce method provides support for Ruby type coercion. It is not enabled by default.
This means that binary operations like + * / or - can often be performed on a BigDecimal and an object of another type, if the other object can be coerced into a BigDecimal value.
e.g.
a = BigDecimal("1.0") b = a / 2.0 #=> 0.5
Note that coercing a String to a BigDecimal is not supported by default; it requires a special compile-time option when building Ruby.
Returns the numerator.
Rational(7).numerator #=> 7 Rational(7, 1).numerator #=> 7 Rational(9, -4).numerator #=> -9 Rational(-2, -10).numerator #=> 1
Returns the largest number less than or equal to rat with a precision of ndigits decimal digits (default: 0).
When the precision is negative, the returned value is an integer with at least ndigits.abs trailing zeros.
Returns a rational when ndigits is positive, otherwise returns an integer.
Rational(3).floor #=> 3 Rational(2, 3).floor #=> 0 Rational(-3, 2).floor #=> -2 # decimal - 1 2 3 . 4 5 6 # ^ ^ ^ ^ ^ ^ # precision -3 -2 -1 0 +1 +2 Rational('-123.456').floor(+1).to_f #=> -123.5 Rational('-123.456').floor(-1) #=> -130