Results for: "Array"

ClosedQueueError

The exception class which will be raised when pushing into a closed Queue. See Queue#close and SizedQueue#close.

TracePoint

Document-class: TracePoint

A class that provides the functionality of Kernel#set_trace_func in a nice Object-Oriented API.

Example

We can use TracePoint to gather information specifically for exceptions:

trace = TracePoint.new(:raise) do |tp|
    p [tp.lineno, tp.event, tp.raised_exception]
end
#=> #<TracePoint:disabled>

trace.enable
#=> false

0 / 0
#=> [5, :raise, #<ZeroDivisionError: divided by 0>]

Events

If you don’t specify the type of events you want to listen for, TracePoint will include all available events.

Note do not depend on current event set, as this list is subject to change. Instead, it is recommended you specify the type of events you want to use.

To filter what is traced, you can pass any of the following as events:

:line

execute code on a new line

:class

start a class or module definition

:end

finish a class or module definition

:call

call a Ruby method

:return

return from a Ruby method

:c_call

call a C-language routine

:c_return

return from a C-language routine

:raise

raise an exception

:b_call

event hook at block entry

:b_return

event hook at block ending

:thread_begin

event hook at thread beginning

:thread_end

event hook at thread ending

:fiber_switch

event hook at fiber switch

:script_compiled

new Ruby code compiled (with eval, load or require)

UncaughtThrowError

Raised when throw is called with a tag which does not have corresponding catch block.

throw "foo", "bar"

raises the exception:

UncaughtThrowError: uncaught throw "foo"

HTTPRequestURITooLong

No documentation available

Enumerable

The Enumerable mixin provides collection classes with several traversal and searching methods, and with the ability to sort. The class must provide a method each, which yields successive members of the collection. If Enumerable#max, min, or sort is used, the objects in the collection must also implement a meaningful <=> operator, as these methods rely on an ordering between members of the collection.

Errno

Ruby exception objects are subclasses of Exception. However, operating systems typically report errors using plain integers. Module Errno is created dynamically to map these operating system errors to Ruby classes, with each error number generating its own subclass of SystemCallError. As the subclass is created in module Errno, its name will start Errno::.

The names of the Errno:: classes depend on the environment in which Ruby runs. On a typical Unix or Windows platform, there are Errno classes such as Errno::EACCES, Errno::EAGAIN, Errno::EINTR, and so on.

The integer operating system error number corresponding to a particular error is available as the class constant Errno::error::Errno.

Errno::EACCES::Errno   #=> 13
Errno::EAGAIN::Errno   #=> 11
Errno::EINTR::Errno    #=> 4

The full list of operating system errors on your particular platform are available as the constants of Errno.

Errno.constants   #=> :E2BIG, :EACCES, :EADDRINUSE, :EADDRNOTAVAIL, ...

Warning

The Warning module contains a single method named warn, and the module extends itself, making Warning.warn available. Warning.warn is called for all warnings issued by Ruby. By default, warnings are printed to $stderr.

Changing the behavior of Warning.warn is useful to customize how warnings are handled by Ruby, for instance by filtering some warnings, and/or outputting warnings somewhere other than $stderr.

If you want to change the behavior of Warning.warn you should use +Warning.extend(MyNewModuleWithWarnMethod)+ and you can use ‘super` to get the default behavior of printing the warning to $stderr.

Example:

module MyWarningFilter
  def warn(message, category: nil, **kwargs)
    if /some warning I want to ignore/.matches?(message)
      # ignore
    else
      super
    end
  end
end
Warning.extend MyWarningFilter

You should never redefine Warning#warn (the instance method), as that will then no longer provide a way to use the default behavior.

The warning gem provides convenient ways to customize Warning.warn.

Coverage

Coverage provides coverage measurement feature for Ruby. This feature is experimental, so these APIs may be changed in future.

Usage

  1. require “coverage”

  2. do Coverage.start

  3. require or load Ruby source file

  4. Coverage.result will return a hash that contains filename as key and coverage array as value. A coverage array gives, for each line, the number of line execution by the interpreter. A nil value means coverage is disabled for this line (lines like else and end).

Examples 

[foo.rb]
s = 0
10.times do |x|
  s += x
end

if s == 45
  p :ok
else
  p :ng
end
[EOF]

require "coverage"
Coverage.start
require "foo.rb"
p Coverage.result  #=> {"foo.rb"=>[1, 1, 10, nil, nil, 1, 1, nil, 0, nil]}

Lines Coverage

If a coverage mode is not explicitly specified when starting coverage, lines coverage is what will run. It reports the number of line executions for each line.

require "coverage"
Coverage.start(lines: true)
require "foo.rb"
p Coverage.result #=> {"foo.rb"=>{:lines=>[1, 1, 10, nil, nil, 1, 1, nil, 0, nil]}}

The value of the lines coverage result is an array containing how many times each line was executed. Order in this array is important. For example, the first item in this array, at index 0, reports how many times line 1 of this file was executed while coverage was run (which, in this example, is one time).

A nil value means coverage is disabled for this line (lines like else and end).

Oneshot Lines Coverage

Oneshot lines coverage tracks and reports on the executed lines while coverage is running. It will not report how many times a line was executed, only that it was executed.

require "coverage"
Coverage.start(oneshot_lines: true)
require "foo.rb"
p Coverage.result #=> {"foo.rb"=>{:oneshot_lines=>[1, 2, 3, 6, 7]}}

The value of the oneshot lines coverage result is an array containing the line numbers that were executed.

Branches Coverage

Branches coverage reports how many times each branch within each conditional was executed.

require "coverage"
Coverage.start(branches: true)
require "foo.rb"
p Coverage.result #=> {"foo.rb"=>{:branches=>{[:if, 0, 6, 0, 10, 3]=>{[:then, 1, 7, 2, 7, 7]=>1, [:else, 2, 9, 2, 9, 7]=>0}}}}

Each entry within the branches hash is a conditional, the value of which is another hash where each entry is a branch in that conditional. The values are the number of times the method was executed, and the keys are identifying information about the branch.

The information that makes up each key identifying branches or conditionals is the following, from left to right:

  1. A label for the type of branch or conditional.

  2. A unique identifier.

  3. The starting line number it appears on in the file.

  4. The starting column number it appears on in the file.

  5. The ending line number it appears on in the file.

  6. The ending column number it appears on in the file.

Methods Coverage

Methods coverage reports how many times each method was executed.

[foo_method.rb]
class Greeter
  def greet
    "welcome!"
  end
end

def hello
  "Hi"
end

hello()
Greeter.new.greet()
[EOF]

require "coverage"
Coverage.start(methods: true)
require "foo_method.rb"
p Coverage.result #=> {"foo_method.rb"=>{:methods=>{[Object, :hello, 7, 0, 9, 3]=>1, [Greeter, :greet, 2, 2, 4, 5]=>1}}}

Each entry within the methods hash represents a method. The values in this hash are the number of times the method was executed, and the keys are identifying information about the method.

The information that makes up each key identifying a method is the following, from left to right:

  1. The class.

  2. The method name.

  3. The starting line number the method appears on in the file.

  4. The starting column number the method appears on in the file.

  5. The ending line number the method appears on in the file.

  6. The ending column number the method appears on in the file.

All Coverage Modes

You can also run all modes of coverage simultaneously with this shortcut. Note that running all coverage modes does not run both lines and oneshot lines. Those modes cannot be run simultaneously. Lines coverage is run in this case, because you can still use it to determine whether or not a line was executed.

require "coverage"
Coverage.start(:all)
require "foo.rb"
p Coverage.result #=> {"foo.rb"=>{:lines=>[1, 1, 10, nil, nil, 1, 1, nil, 0, nil], :branches=>{[:if, 0, 6, 0, 10, 3]=>{[:then, 1, 7, 2, 7, 7]=>1, [:else, 2, 9, 2, 9, 7]=>0}}, :methods=>{}}}

Racc

Racc is a LALR(1) parser generator. It is written in Ruby itself, and generates Ruby programs.

Command-line Reference 

racc [-o<var>filename</var>] [--output-file=<var>filename</var>]
     [-e<var>rubypath</var>] [--executable=<var>rubypath</var>]
     [-v] [--verbose]
     [-O<var>filename</var>] [--log-file=<var>filename</var>]
     [-g] [--debug]
     [-E] [--embedded]
     [-l] [--no-line-convert]
     [-c] [--line-convert-all]
     [-a] [--no-omit-actions]
     [-C] [--check-only]
     [-S] [--output-status]
     [--version] [--copyright] [--help] <var>grammarfile</var>
grammarfile

Racc grammar file. Any extension is permitted.

-o+outfile+, –output-file=outfile

A filename for output. default is <filename>.tab.rb

-O+filename+, –log-file=filename

Place logging output in file filename. Default log file name is <filename>.output.

-e+rubypath+, –executable=rubypath

output executable file(mode 755). where path is the Ruby interpreter.

-v, –verbose

verbose mode. create filename.output file, like yacc’s y.output file.

-g, –debug

add debug code to parser class. To display debuggin information, use this ‘-g’ option and set @yydebug true in parser class.

-E, –embedded

Output parser which doesn’t need runtime files (racc/parser.rb).

-C, –check-only

Check syntax of racc grammar file and quit.

-S, –output-status

Print messages time to time while compiling.

-l, –no-line-convert

turns off line number converting.

-c, –line-convert-all

Convert line number of actions, inner, header and footer.

-a, –no-omit-actions

Call all actions, even if an action is empty.

–version

print Racc version and quit.

–copyright

Print copyright and quit.

–help

Print usage and quit.

Generating Parser Using Racc

To compile Racc grammar file, simply type:

$ racc parse.y

This creates Ruby script file “parse.tab.y”. The -o option can change the output filename.

Writing A Racc Grammar File

If you want your own parser, you have to write a grammar file. A grammar file contains the name of your parser class, grammar for the parser, user code, and anything else. When writing a grammar file, yacc’s knowledge is helpful. If you have not used yacc before, Racc is not too difficult.

Here’s an example Racc grammar file.

class Calcparser
rule
  target: exp { print val[0] }

  exp: exp '+' exp
     | exp '*' exp
     | '(' exp ')'
     | NUMBER
end

Racc grammar files resemble yacc files. But (of course), this is Ruby code. yacc’s $$ is the ‘result’, $0, $1… is an array called ‘val’, and $-1, $-2… is an array called ‘_values’.

See the Grammar File Reference for more information on grammar files.

Parser

Then you must prepare the parse entry method. There are two types of parse methods in Racc, Racc::Parser#do_parse and Racc::Parser#yyparse

Racc::Parser#do_parse is simple.

It’s yyparse() of yacc, and Racc::Parser#next_token is yylex(). This method must returns an array like [TOKENSYMBOL, ITS_VALUE]. EOF is [false, false]. (TOKENSYMBOL is a Ruby symbol (taken from String#intern) by default. If you want to change this, see the grammar reference.

Racc::Parser#yyparse is little complicated, but useful. It does not use Racc::Parser#next_token, instead it gets tokens from any iterator.

For example, yyparse(obj, :scan) causes calling +obj#scan+, and you can return tokens by yielding them from +obj#scan+.

Debugging

When debugging, “-v” or/and the “-g” option is helpful.

“-v” creates verbose log file (.output). “-g” creates a “Verbose Parser”. Verbose Parser prints the internal status when parsing. But it’s not automatic. You must use -g option and set +@yydebug+ to true in order to get output. -g option only creates the verbose parser.

Racc reported syntax error.

Isn’t there too many “end”? grammar of racc file is changed in v0.10.

Racc does not use ‘%’ mark, while yacc uses huge number of ‘%’ marks..

Racc reported “XXXX conflicts”.

Try “racc -v xxxx.y”. It causes producing racc’s internal log file, xxxx.output.

Generated parsers does not work correctly

Try “racc -g xxxx.y”. This command let racc generate “debugging parser”. Then set @yydebug=true in your parser. It produces a working log of your parser.

Re-distributing Racc runtime

A parser, which is created by Racc, requires the Racc runtime module; racc/parser.rb.

Ruby 1.8.x comes with Racc runtime module, you need NOT distribute Racc runtime files.

If you want to include the Racc runtime module with your parser. This can be done by using ‘-E’ option:

$ racc -E -omyparser.rb myparser.y

This command creates myparser.rb which ‘includes’ Racc runtime. Only you must do is to distribute your parser file (myparser.rb).

Note: parser.rb is ruby license, but your parser is not. Your own parser is completely yours.

Benchmark

The Benchmark module provides methods to measure and report the time used to execute Ruby code.

The result:

              user     system      total        real
for:      1.010000   0.000000   1.010000 (  1.015688)
times:    1.000000   0.000000   1.000000 (  1.003611)
upto:     1.030000   0.000000   1.030000 (  1.028098)

Forwardable

The Forwardable module provides delegation of specified methods to a designated object, using the methods def_delegator and def_delegators.

For example, say you have a class RecordCollection which contains an array @records. You could provide the lookup method record_number(), which simply calls [] on the @records array, like this:

require 'forwardable'

class RecordCollection
  attr_accessor :records
  extend Forwardable
  def_delegator :@records, :[], :record_number
end

We can use the lookup method like so:

r = RecordCollection.new
r.records = [4,5,6]
r.record_number(0)  # => 4

Further, if you wish to provide the methods size, <<, and map, all of which delegate to @records, this is how you can do it:

class RecordCollection # re-open RecordCollection class
  def_delegators :@records, :size, :<<, :map
end

r = RecordCollection.new
r.records = [1,2,3]
r.record_number(0)   # => 1
r.size               # => 3
r << 4               # => [1, 2, 3, 4]
r.map { |x| x * 2 }  # => [2, 4, 6, 8]

You can even extend regular objects with Forwardable.

my_hash = Hash.new
my_hash.extend Forwardable              # prepare object for delegation
my_hash.def_delegator "STDOUT", "puts"  # add delegation for STDOUT.puts()
my_hash.puts "Howdy!"

Another example

You could use Forwardable as an alternative to inheritance, when you don’t want to inherit all methods from the superclass. For instance, here is how you might add a range of Array instance methods to a new class Queue:

class Queue
  extend Forwardable

  def initialize
    @q = [ ]    # prepare delegate object
  end

  # setup preferred interface, enq() and deq()...
  def_delegator :@q, :push, :enq
  def_delegator :@q, :shift, :deq

  # support some general Array methods that fit Queues well
  def_delegators :@q, :clear, :first, :push, :shift, :size
end

q = Queue.new
q.enq 1, 2, 3, 4, 5
q.push 6

q.shift    # => 1
while q.size > 0
  puts q.deq
end

q.enq "Ruby", "Perl", "Python"
puts q.first
q.clear
puts q.first

This should output:

2
3
4
5
6
Ruby
nil

Notes

Be advised, RDoc will not detect delegated methods.

forwardable.rb provides single-method delegation via the def_delegator and def_delegators methods. For full-class delegation via DelegateClass, see delegate.rb.

SingleForwardable

SingleForwardable can be used to setup delegation at the object level as well.

printer = String.new
printer.extend SingleForwardable        # prepare object for delegation
printer.def_delegator "STDOUT", "puts"  # add delegation for STDOUT.puts()
printer.puts "Howdy!"

Also, SingleForwardable can be used to set up delegation for a Class or Module.

class Implementation
  def self.service
    puts "serviced!"
  end
end

module Facade
  extend SingleForwardable
  def_delegator :Implementation, :service
end

Facade.service #=> serviced!

If you want to use both Forwardable and SingleForwardable, you can use methods def_instance_delegator and def_single_delegator, etc.

Rake

No documentation available

SecureRandom

Secure random number generator interface.

This library is an interface to secure random number generators which are suitable for generating session keys in HTTP cookies, etc.

You can use this library in your application by requiring it:

require 'securerandom'

It supports the following secure random number generators:

SecureRandom is extended by the Random::Formatter module which defines the following methods:

These methods are usable as class methods of SecureRandom such as ‘SecureRandom.hex`.

Examples

Generate random hexadecimal strings:

require 'securerandom'

SecureRandom.hex(10) #=> "52750b30ffbc7de3b362"
SecureRandom.hex(10) #=> "92b15d6c8dc4beb5f559"
SecureRandom.hex(13) #=> "39b290146bea6ce975c37cfc23"

Generate random base64 strings:

SecureRandom.base64(10) #=> "EcmTPZwWRAozdA=="
SecureRandom.base64(10) #=> "KO1nIU+p9DKxGg=="
SecureRandom.base64(12) #=> "7kJSM/MzBJI+75j8"

Generate random binary strings:

SecureRandom.random_bytes(10) #=> "\016\t{\370g\310pbr\301"
SecureRandom.random_bytes(10) #=> "\323U\030TO\234\357\020\a\337"

Generate alphanumeric strings:

SecureRandom.alphanumeric(10) #=> "S8baxMJnPl"
SecureRandom.alphanumeric(10) #=> "aOxAg8BAJe"

Generate UUIDs:

SecureRandom.uuid #=> "2d931510-d99f-494a-8c67-87feb05e1594"
SecureRandom.uuid #=> "bad85eb9-0713-4da7-8d36-07a8e4b00eab"

Marshal

The marshaling library converts collections of Ruby objects into a byte stream, allowing them to be stored outside the currently active script. This data may subsequently be read and the original objects reconstituted.

Marshaled data has major and minor version numbers stored along with the object information. In normal use, marshaling can only load data written with the same major version number and an equal or lower minor version number. If Ruby’s “verbose” flag is set (normally using -d, -v, -w, or –verbose) the major and minor numbers must match exactly. Marshal versioning is independent of Ruby’s version numbers. You can extract the version by reading the first two bytes of marshaled data.

str = Marshal.dump("thing")
RUBY_VERSION   #=> "1.9.0"
str[0].ord     #=> 4
str[1].ord     #=> 8

Some objects cannot be dumped: if the objects to be dumped include bindings, procedure or method objects, instances of class IO, or singleton objects, a TypeError will be raised.

If your class has special serialization needs (for example, if you want to serialize in some specific format), or if it contains objects that would otherwise not be serializable, you can implement your own serialization strategy.

There are two methods of doing this, your object can define either marshal_dump and marshal_load or _dump and _load. marshal_dump will take precedence over _dump if both are defined. marshal_dump may result in smaller Marshal strings.

Security considerations

By design, Marshal.load can deserialize almost any class loaded into the Ruby process. In many cases this can lead to remote code execution if the Marshal data is loaded from an untrusted source.

As a result, Marshal.load is not suitable as a general purpose serialization format and you should never unmarshal user supplied input or other untrusted data.

If you need to deserialize untrusted data, use JSON or another serialization format that is only able to load simple, ‘primitive’ types such as String, Array, Hash, etc. Never allow user input to specify arbitrary types to deserialize into.

marshal_dump and marshal_load

When dumping an object the method marshal_dump will be called. marshal_dump must return a result containing the information necessary for marshal_load to reconstitute the object. The result can be any object.

When loading an object dumped using marshal_dump the object is first allocated then marshal_load is called with the result from marshal_dump. marshal_load must recreate the object from the information in the result.

Example:

class MyObj
  def initialize name, version, data
    @name    = name
    @version = version
    @data    = data
  end

  def marshal_dump
    [@name, @version]
  end

  def marshal_load array
    @name, @version = array
  end
end

_dump and _load

Use _dump and _load when you need to allocate the object you’re restoring yourself.

When dumping an object the instance method _dump is called with an Integer which indicates the maximum depth of objects to dump (a value of -1 implies that you should disable depth checking). _dump must return a String containing the information necessary to reconstitute the object.

The class method _load should take a String and use it to return an object of the same class.

Example:

class MyObj
  def initialize name, version, data
    @name    = name
    @version = version
    @data    = data
  end

  def _dump level
    [@name, @version].join ':'
  end

  def self._load args
    new(*args.split(':'))
  end
end

Since Marshal.dump outputs a string you can have _dump return a Marshal string which is Marshal.loaded in _load for complex objects.

WIN32OLE_VARIABLE

WIN32OLE_VARIABLE objects represent OLE variable information.

WIN32OLE_VARIANT

WIN32OLE_VARIANT objects represents OLE variant.

Win32OLE converts Ruby object into OLE variant automatically when invoking OLE methods. If OLE method requires the argument which is different from the variant by automatic conversion of Win32OLE, you can convert the specfied variant type by using WIN32OLE_VARIANT class.

param = WIN32OLE_VARIANT.new(10, WIN32OLE::VARIANT::VT_R4)
oleobj.method(param)

WIN32OLE_VARIANT does not support VT_RECORD variant. Use WIN32OLE_RECORD class instead of WIN32OLE_VARIANT if the VT_RECORD variant is needed.

OpenSSL::Random::RandomError

No documentation available

Net::IMAP::ResponseParseError

Error raised when a response from the server is non-parseable.

Racc::ParserFileGenerator::Params

No documentation available

Gem::Package::TarInvalidError

Raised when a tar file is corrupt

Gem::Package::TarReader

TarReader reads tar files and allows iteration over their items

Gem::S3URISigner::ConfigurationError

No documentation available

Enumerator::Generator

Generator

Enumerator::ArithmeticSequence

Enumerator::ArithmeticSequence is a subclass of Enumerator, that is a representation of sequences of numbers with common difference. Instances of this class can be generated by the Range#step and Numeric#step methods.

The class can be used for slicing Array (see Array#slice) or custom collections.

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