Results for: "to_proc"

Raised when Ruby can’t yield as requested.

A typical scenario is attempting to yield when no block is given:

def call_block
  yield 42
end
call_block

raises the exception:

LocalJumpError: no block given (yield)

A more subtle example:

def get_me_a_return
  Proc.new { return 42 }
end
get_me_a_return.call

raises the exception:

LocalJumpError: unexpected return

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"

Profile provides a way to Profile your Ruby application.

Profiling your program is a way of determining which methods are called and how long each method takes to complete. This way you can detect which methods are possible bottlenecks.

Profiling your program will slow down your execution time considerably, so activate it only when you need it. Don’t confuse benchmarking with profiling.

There are two ways to activate Profiling:

Command line

Run your Ruby script with -rprofile:

ruby -rprofile example.rb

If you’re profiling an executable in your $PATH you can use ruby -S:

ruby -rprofile -S some_executable

From code

Just require ‘profile’:

require 'profile'

def slow_method
  5000.times do
    9999999999999999*999999999
  end
end

def fast_method
  5000.times do
    9999999999999999+999999999
  end
end

slow_method
fast_method

The output in both cases is a report when the execution is over:

ruby -rprofile example.rb

  %   cumulative   self              self     total
 time   seconds   seconds    calls  ms/call  ms/call  name
 68.42     0.13      0.13        2    65.00    95.00  Integer#times
 15.79     0.16      0.03     5000     0.01     0.01  Fixnum#*
 15.79     0.19      0.03     5000     0.01     0.01  Fixnum#+
  0.00     0.19      0.00        2     0.00     0.00  IO#set_encoding
  0.00     0.19      0.00        1     0.00   100.00  Object#slow_method
  0.00     0.19      0.00        2     0.00     0.00  Module#method_added
  0.00     0.19      0.00        1     0.00    90.00  Object#fast_method
  0.00     0.19      0.00        1     0.00   190.00  #toplevel

418 I’m a teapot - RFC 2324; a joke RFC 420 Enhance Your Calm - Twitter

In order to execute a command on your OS, you need to define it as a Shell method.

Alternatively, you can execute any command via Shell::CommandProcessor#system even if it is not defined.

Raised when the address is an invalid length.

TupleSpaceProxy allows a remote Tuplespace to appear as local.

RingProvider uses a RingServer advertised TupleSpace as a name service. TupleSpace clients can register themselves with the remote TupleSpace and look up other provided services via the remote TupleSpace.

Services are registered with a tuple of the format [:name, klass, DRbObject, description].

RSS, being an XML-based format, has namespace support. If two namespaces are declared with the same name, an OverlappedPrefixError will be raised.

An error that indicates we weren’t able to fetch some data from a source

An HTTP Proxy server which proxies GET, HEAD and POST requests.

To create a simple proxy server:

require 'webrick'
require 'webrick/httpproxy'

proxy = WEBrick::HTTPProxyServer.new Port: 8000

trap 'INT'  do proxy.shutdown end
trap 'TERM' do proxy.shutdown end

proxy.start

See ::new for proxy-specific configuration items.

Modifying proxied responses

To modify content the proxy server returns use the :ProxyContentHandler option:

handler = proc do |req, res|
  if res['content-type'] == 'text/plain' then
    res.body << "\nThis content was proxied!\n"
  end
end

proxy =
  WEBrick::HTTPProxyServer.new Port: 8000, ProxyContentHandler: handler

The GC profiler provides access to information on GC runs including time, length and object space size.

Example:

GC::Profiler.enable

require 'rdoc/rdoc'

GC::Profiler.report

GC::Profiler.disable

See also GC.count, GC.malloc_allocated_size and GC.malloc_allocations

Nonsymmetric reduction from Hessenberg to real Schur form.

Returns a Ruby lighter-weight code representation of this specification, used for indexing only.

See to_ruby.

Raised when an invalid operation is attempted on a Fiber, in particular when attempting to call/resume a dead fiber, attempting to yield from the root fiber, or calling a fiber across threads.

fiber = Fiber.new{}
fiber.resume #=> nil
fiber.resume #=> FiberError: dead fiber called

The most standard error types are subclasses of StandardError. A rescue clause without an explicit Exception class will rescue all StandardErrors (and only those).

def foo
  raise "Oups"
end
foo rescue "Hello"   #=> "Hello"

On the other hand:

require 'does/not/exist' rescue "Hi"

raises the exception:

LoadError: no such file to load -- does/not/exist