Results for: "Array.new"

JSON#fast_generate

Generate a JSON document from the Ruby data structure obj and return it. This method disables the checks for circles in Ruby objects.

WARNING: Be careful not to pass any Ruby data structures with circles as obj argument because this will cause JSON to go into an infinite loop.

JSON#pretty_generate

Generate a JSON document from the Ruby data structure obj and return it. The returned document is a prettier form of the document returned by unparse.

The opts argument can be used to configure the generator. See the generate method for a more detailed explanation.

ObjectSpace::allocation_generation

Returns garbage collector generation for the given object.

class B
  include ObjectSpace

  def foo
    trace_object_allocations do
      obj = Object.new
      p "Generation is #{allocation_generation(obj)}"
    end
  end
end

B.new.foo #=> "Generation is 3"

See ::trace_object_allocations for more information and examples.

Returns whether or not the given entry point func can be found within lib. If func is nil, the main() entry point is used by default. If found, it adds the library to list of libraries to be used when linking your extension.

If headers are provided, it will include those header files as the header files it looks in when searching for func.

The real name of the library to be linked can be altered by --with-FOOlib configuration option.

MakeMakefile#find_library

Returns whether or not the entry point func can be found within the library lib in one of the paths specified, where paths is an array of strings. If func is nil , then the main() function is used as the entry point.

If lib is found, then the path it was found on is added to the list of library paths searched and linked against.

MakeMakefile#have_framework

Returns whether or not the given framework can be found on your system. If found, a macro is passed as a preprocessor constant to the compiler using the framework name, in uppercase, prepended with HAVE_FRAMEWORK_.

For example, if have_framework('Ruby') returned true, then the HAVE_FRAMEWORK_RUBY preprocessor macro would be passed to the compiler.

If fw is a pair of the framework name and its header file name that header file is checked, instead of the normally used header file which is named same as the framework.

MakeMakefile#check_signedness

Returns the signedness of the given type. You may optionally specify additional headers to search in for the type.

If the type is found and is a numeric type, a macro is passed as a preprocessor constant to the compiler using the type name, in uppercase, prepended with SIGNEDNESS_OF_, followed by the type name, followed by =X where “X” is positive integer if the type is unsigned and a negative integer if the type is signed.

For example, if size_t is defined as unsigned, then check_signedness('size_t') would return +1 and the SIGNEDNESS_OF_SIZE_T=+1 preprocessor macro would be passed to the compiler. The SIGNEDNESS_OF_INT=-1 macro would be set for check_signedness('int')

Open3#pipeline_start

Open3.pipeline_start starts a list of commands as a pipeline. No pipes are created for stdin of the first command and stdout of the last command.

Open3.pipeline_start(cmd1, cmd2, ... [, opts]) {|wait_threads|
  ...
}

wait_threads = Open3.pipeline_start(cmd1, cmd2, ... [, opts])
...

Each cmd is a string or an array. If it is an array, the elements are passed to Process.spawn.

cmd:
  commandline                              command line string which is passed to a shell
  [env, commandline, opts]                 command line string which is passed to a shell
  [env, cmdname, arg1, ..., opts]          command name and one or more arguments (no shell)
  [env, [cmdname, argv0], arg1, ..., opts] command name and arguments including argv[0] (no shell)

Note that env and opts are optional, as for Process.spawn.

Example:

# Run xeyes in 10 seconds.
Open3.pipeline_start("xeyes") {|ts|
  sleep 10
  t = ts[0]
  Process.kill("TERM", t.pid)
  p t.value #=> #<Process::Status: pid 911 SIGTERM (signal 15)>
}

# Convert pdf to ps and send it to a printer.
# Collect error message of pdftops and lpr.
pdf_file = "paper.pdf"
printer = "printer-name"
err_r, err_w = IO.pipe
Open3.pipeline_start(["pdftops", pdf_file, "-"],
                     ["lpr", "-P#{printer}"],
                     :err=>err_w) {|ts|
  err_w.close
  p err_r.read # error messages of pdftops and lpr.
}

Open3::pipeline_start

Open3.pipeline_start starts a list of commands as a pipeline. No pipes are created for stdin of the first command and stdout of the last command.

Open3.pipeline_start(cmd1, cmd2, ... [, opts]) {|wait_threads|
  ...
}

wait_threads = Open3.pipeline_start(cmd1, cmd2, ... [, opts])
...

Each cmd is a string or an array. If it is an array, the elements are passed to Process.spawn.

cmd:
  commandline                              command line string which is passed to a shell
  [env, commandline, opts]                 command line string which is passed to a shell
  [env, cmdname, arg1, ..., opts]          command name and one or more arguments (no shell)
  [env, [cmdname, argv0], arg1, ..., opts] command name and arguments including argv[0] (no shell)

Note that env and opts are optional, as for Process.spawn.

Example:

# Run xeyes in 10 seconds.
Open3.pipeline_start("xeyes") {|ts|
  sleep 10
  t = ts[0]
  Process.kill("TERM", t.pid)
  p t.value #=> #<Process::Status: pid 911 SIGTERM (signal 15)>
}

# Convert pdf to ps and send it to a printer.
# Collect error message of pdftops and lpr.
pdf_file = "paper.pdf"
printer = "printer-name"
err_r, err_w = IO.pipe
Open3.pipeline_start(["pdftops", pdf_file, "-"],
                     ["lpr", "-P#{printer}"],
                     :err=>err_w) {|ts|
  err_w.close
  p err_r.read # error messages of pdftops and lpr.
}

Gem::path_separator

How String Gem paths should be split. Overridable for esoteric platforms.

Object#instance_variable_defined?

Returns true if the given instance variable is defined in obj. String arguments are converted to symbols.

class Fred
  def initialize(p1, p2)
    @a, @b = p1, p2
  end
end
fred = Fred.new('cat', 99)
fred.instance_variable_defined?(:@a)    #=> true
fred.instance_variable_defined?("@b")   #=> true
fred.instance_variable_defined?("@c")   #=> false

Module#class_variable_defined?

Returns true if the given class variable is defined in obj. String arguments are converted to symbols.

class Fred
  @@foo = 99
end
Fred.class_variable_defined?(:@@foo)    #=> true
Fred.class_variable_defined?(:@@bar)    #=> false

WIN32OLE_METHOD#size_opt_params

Returns the size of optional parameters.

tobj = WIN32OLE_TYPE.new('Microsoft Excel 9.0 Object Library', 'Workbook')
method = WIN32OLE_METHOD.new(tobj, 'SaveAs')
puts method.size_opt_params # => 4

Binding#local_variable_defined?

Returns true if a local variable symbol exists.

def foo
  a = 1
  binding.local_variable_defined?(:a) #=> true
  binding.local_variable_defined?(:b) #=> false
end

This method is the short version of the following code:

binding.eval("defined?(#{symbol}) == 'local-variable'")

Shell::default_record_separator

No documentation available

Shell::default_record_separator=

No documentation available

Readline::completion_append_character=

Specifies a character to be appended on completion. Nothing will be appended if an empty string (“”) or nil is specified.

For example:

require "readline"

Readline.readline("> ", true)
Readline.completion_append_character = " "

Result:

>
Input "/var/li".

> /var/li
Press TAB key.

> /var/lib
Completes "b" and appends " ". So, you can continuously input "/usr".

> /var/lib /usr

NOTE: Only one character can be specified. When “string” is specified, sets only “s” that is the first.

require "readline"

Readline.completion_append_character = "string"
p Readline.completion_append_character # => "s"