Globs for files matching pattern inside of directory, returning absolute paths to the matching files.
An Encoding instance represents a character encoding usable in Ruby. It is defined as a constant under the Encoding namespace. It has a name and, optionally, aliases:
Encoding::US_ASCII.name # => "US-ASCII" Encoding::US_ASCII.names # => ["US-ASCII", "ASCII", "ANSI_X3.4-1968", "646"]
A Ruby method that accepts an encoding as an argument will accept:
An Encoding object.
The name of an encoding.
An alias for an encoding name.
These are equivalent:
'foo'.encode(Encoding::US_ASCII) # Encoding object. 'foo'.encode('US-ASCII') # Encoding name. 'foo'.encode('ASCII') # Encoding alias.
For a full discussion of encodings and their uses, see the Encodings document.
Encoding::ASCII_8BIT is a special-purpose encoding that is usually used for a string of bytes, not a string of characters. But as the name indicates, its characters in the ASCII range are considered as ASCII characters. This is useful when you use other ASCII-compatible encodings.
EncodingError is the base class for encoding errors.
Objects of class Binding encapsulate the execution context at some particular place in the code and retain this context for future use. The variables, methods, value of self, and possibly an iterator block that can be accessed in this context are all retained. Binding objects can be created using Kernel#binding, and are made available to the callback of Kernel#set_trace_func and instances of TracePoint.
These binding objects can be passed as the second argument of the Kernel#eval method, establishing an environment for the evaluation.
class Demo def initialize(n) @secret = n end def get_binding binding end end k1 = Demo.new(99) b1 = k1.get_binding k2 = Demo.new(-3) b2 = k2.get_binding eval("@secret", b1) #=> 99 eval("@secret", b2) #=> -3 eval("@secret") #=> nil
Binding objects have no class-specific methods.
MatchData encapsulates the result of matching a Regexp against string. It is returned by Regexp#match and String#match, and also stored in a global variable returned by Regexp.last_match.
Usage:
url = 'https://docs.ruby-lang.org/en/2.5.0/MatchData.html' m = url.match(/(\d\.?)+/) # => #<MatchData "2.5.0" 1:"0"> m.string # => "https://docs.ruby-lang.org/en/2.5.0/MatchData.html" m.regexp # => /(\d\.?)+/ # entire matched substring: m[0] # => "2.5.0" # Working with unnamed captures m = url.match(%r{([^/]+)/([^/]+)\.html$}) m.captures # => ["2.5.0", "MatchData"] m[1] # => "2.5.0" m.values_at(1, 2) # => ["2.5.0", "MatchData"] # Working with named captures m = url.match(%r{(?<version>[^/]+)/(?<module>[^/]+)\.html$}) m.captures # => ["2.5.0", "MatchData"] m.named_captures # => {"version"=>"2.5.0", "module"=>"MatchData"} m[:version] # => "2.5.0" m.values_at(:version, :module) # => ["2.5.0", "MatchData"] # Numerical indexes are working, too m[1] # => "2.5.0" m.values_at(1, 2) # => ["2.5.0", "MatchData"]
Parts of last MatchData (returned by Regexp.last_match) are also aliased as global variables:
$~ is Regexp.last_match;
$& is Regexp.last_match[ 0 ];
$1, $2, and so on are Regexp.last_match[ i ] (captures by number);
$` is Regexp.last_match.pre_match;
$' is Regexp.last_match.post_match;
$+ is Regexp.last_match[ -1 ] (the last capture).
See also “Special global variables” section in Regexp documentation.
Raised when attempting to divide an integer by 0.
42 / 0 #=> ZeroDivisionError: divided by 0
Note that only division by an exact 0 will raise the exception:
42 / 0.0 #=> Float::INFINITY 42 / -0.0 #=> -Float::INFINITY 0 / 0.0 #=> NaN
This module provides a framework for message digest libraries.
You may want to look at OpenSSL::Digest as it supports more algorithms.
A cryptographic hash function is a procedure that takes data and returns a fixed bit string: the hash value, also known as digest. Hash functions are also called one-way functions, it is easy to compute a digest from a message, but it is infeasible to generate a message from a digest.
require 'digest' # Compute a complete digest Digest::SHA256.digest 'message' #=> "\xABS\n\x13\xE4Y..." sha256 = Digest::SHA256.new sha256.digest 'message' #=> "\xABS\n\x13\xE4Y..." # Other encoding formats Digest::SHA256.hexdigest 'message' #=> "ab530a13e459..." Digest::SHA256.base64digest 'message' #=> "q1MKE+RZFJgr..." # Compute digest by chunks md5 = Digest::MD5.new md5.update 'message1' md5 << 'message2' # << is an alias for update md5.hexdigest #=> "94af09c09bb9..." # Compute digest for a file sha256 = Digest::SHA256.file 'testfile' sha256.hexdigest
Additionally digests can be encoded in “bubble babble” format as a sequence of consonants and vowels which is more recognizable and comparable than a hexadecimal digest.
require 'digest/bubblebabble' Digest::SHA256.bubblebabble 'message' #=> "xopoh-fedac-fenyh-..."
See the bubble babble specification at web.mit.edu/kenta/www/one/bubblebabble/spec/jrtrjwzi/draft-huima-01.txt.
Digest algorithms Different digest algorithms (or hash functions) are available:
MD5
See RFC 1321 The MD5 Message-Digest Algorithm
As Digest::RMD160. See homes.esat.kuleuven.be/~bosselae/ripemd160.html.
SHA1
See FIPS 180 Secure Hash Standard.
SHA2 family
See FIPS 180 Secure Hash Standard which defines the following algorithms:
The latest versions of the FIPS publications can be found here: csrc.nist.gov/publications/PubsFIPS.html.
The DidYouMean gem adds functionality to suggest possible method/class names upon errors such as NameError and NoMethodError. In Ruby 2.3 or later, it is automatically activated during startup.
@example
methosd # => NameError: undefined local variable or method `methosd' for main:Object # Did you mean? methods # method OBject # => NameError: uninitialized constant OBject # Did you mean? Object @full_name = "Yuki Nishijima" first_name, last_name = full_name.split(" ") # => NameError: undefined local variable or method `full_name' for main:Object # Did you mean? @full_name @@full_name = "Yuki Nishijima" @@full_anme # => NameError: uninitialized class variable @@full_anme in Object # Did you mean? @@full_name full_name = "Yuki Nishijima" full_name.starts_with?("Y") # => NoMethodError: undefined method `starts_with?' for "Yuki Nishijima":String # Did you mean? start_with? hash = {foo: 1, bar: 2, baz: 3} hash.fetch(:fooo) # => KeyError: key not found: :fooo # Did you mean? :foo
did_you_mean Occasionally, you may want to disable the did_you_mean gem for e.g. debugging issues in the error object itself. You can disable it entirely by specifying --disable-did_you_mean option to the ruby command:
$ ruby --disable-did_you_mean -e "1.zeor?" -e:1:in `<main>': undefined method `zeor?' for 1:Integer (NameError)
When you do not have direct access to the ruby command (e.g. +rails console+, irb), you could applyoptions using the RUBYOPT environment variable:
$ RUBYOPT='--disable-did_you_mean' irb irb:0> 1.zeor? # => NoMethodError (undefined method `zeor?' for 1:Integer)
Sometimes, you do not want to disable the gem entirely, but need to get the original error message without suggestions (e.g. testing). In this case, you could use the #original_message method on the error object:
no_method_error = begin 1.zeor? rescue NoMethodError => error error end no_method_error.message # => NoMethodError (undefined method `zeor?' for 1:Integer) # Did you mean? zero? no_method_error.original_message # => NoMethodError (undefined method `zeor?' for 1:Integer)
Parent class for redirection (3xx) HTTP response classes.
A redirection response indicates the client must take additional action to complete the request.
References:
Response class for Temporary Redirect responses (status code 307).
The request should be repeated with another URI; however, future requests should still use the original URI.
References:
Response class for Permanent Redirect responses (status code 308).
This and all future requests should be directed to the given URI.
References:
Response class for Misdirected Request responses (status code 421).
The request was directed at a server that is not able to produce a response.
References:
Response class for Precondition Required responses (status code 428).
The origin server requires the request to be conditional.
References:
Raised on redirection, only occurs when redirect option for HTTP is false.
The dispatcher class fires events for nodes that are found while walking an AST to all registered listeners. It’s useful for performing different types of analysis on the AST while only having to walk the tree once.
To use the dispatcher, you would first instantiate it and register listeners for the events you’re interested in:
class OctalListener def on_integer_node_enter(node) if node.octal? && !node.slice.start_with?("0o") warn("Octal integers should be written with the 0o prefix") end end end dispatcher = Dispatcher.new dispatcher.register(listener, :on_integer_node_enter)
Then, you can walk any number of trees and dispatch events to the listeners:
result = Prism.parse("001 + 002 + 003") dispatcher.dispatch(result.value)
Optionally, you can also use ‘#dispatch_once` to dispatch enter and leave events for a single node without recursing further down the tree. This can be useful in circumstances where you want to reuse the listeners you already have registers but want to stop walking the tree at a certain point.
integer = result.value.statements.body.first.receiver.receiver dispatcher.dispatch_once(integer)
FIXME: This isn’t documented in Nutshell.
Since MonitorMixin.new_cond returns a ConditionVariable, and the example above calls while_wait and signal, this class should be documented.