Results for: "module_function"

Writes the given string to ios using the write(2) system call after O_NONBLOCK is set for the underlying file descriptor.

It returns the number of bytes written.

write_nonblock just calls the write(2) system call. It causes all errors the write(2) system call causes: Errno::EWOULDBLOCK, Errno::EINTR, etc. The result may also be smaller than string.length (partial write). The caller should care such errors and partial write.

If the exception is Errno::EWOULDBLOCK or Errno::EAGAIN, it is extended by IO::WaitWritable. So IO::WaitWritable can be used to rescue the exceptions for retrying write_nonblock.

# Creates a pipe.
r, w = IO.pipe

# write_nonblock writes only 65536 bytes and return 65536.
# (The pipe size is 65536 bytes on this environment.)
s = "a" * 100000
p w.write_nonblock(s)     #=> 65536

# write_nonblock cannot write a byte and raise EWOULDBLOCK (EAGAIN).
p w.write_nonblock("b")   # Resource temporarily unavailable (Errno::EAGAIN)

If the write buffer is not empty, it is flushed at first.

When write_nonblock raises an exception kind of IO::WaitWritable, write_nonblock should not be called until io is writable for avoiding busy loop. This can be done as follows.

begin
  result = io.write_nonblock(string)
rescue IO::WaitWritable, Errno::EINTR
  IO.select(nil, [io])
  retry
end

Note that this doesn’t guarantee to write all data in string. The length written is reported as result and it should be checked later.

On some platforms such as Windows, write_nonblock is not supported according to the kind of the IO object. In such cases, write_nonblock raises Errno::EBADF.

By specifying a keyword argument exception to false, you can indicate that write_nonblock should not raise an IO::WaitWritable exception, but return the symbol :wait_writable instead.

See as_json.

Methods BigDecimal#as_json and BigDecimal.json_create may be used to serialize and deserialize a BigDecimal object; see Marshal.

Method BigDecimal#as_json serializes self, returning a 2-element hash representing self:

require 'json/add/bigdecimal'
x = BigDecimal(2).as_json             # => {"json_class"=>"BigDecimal", "b"=>"27:0.2e1"}
y = BigDecimal(2.0, 4).as_json        # => {"json_class"=>"BigDecimal", "b"=>"36:0.2e1"}
z = BigDecimal(Complex(2, 0)).as_json # => {"json_class"=>"BigDecimal", "b"=>"27:0.2e1"}

Method JSON.create deserializes such a hash, returning a BigDecimal object:

BigDecimal.json_create(x) # => 0.2e1
BigDecimal.json_create(y) # => 0.2e1
BigDecimal.json_create(z) # => 0.2e1

Returns a JSON string representing self:

require 'json/add/bigdecimal'
puts BigDecimal(2).to_json
puts BigDecimal(2.0, 4).to_json
puts BigDecimal(Complex(2, 0)).to_json

Output:

{"json_class":"BigDecimal","b":"27:0.2e1"}
{"json_class":"BigDecimal","b":"36:0.2e1"}
{"json_class":"BigDecimal","b":"27:0.2e1"}

See as_json.

Methods OpenStruct#as_json and OpenStruct.json_create may be used to serialize and deserialize a OpenStruct object; see Marshal.

Method OpenStruct#as_json serializes self, returning a 2-element hash representing self:

require 'json/add/ostruct'
x = OpenStruct.new('name' => 'Rowdy', :age => nil).as_json
# => {"json_class"=>"OpenStruct", "t"=>{:name=>'Rowdy', :age=>nil}}

Method JSON.create deserializes such a hash, returning a OpenStruct object:

OpenStruct.json_create(x)
# => #<OpenStruct name='Rowdy', age=nil>

Returns a JSON string representing self:

require 'json/add/ostruct'
puts OpenStruct.new('name' => 'Rowdy', :age => nil).to_json

Output:

{"json_class":"OpenStruct","t":{'name':'Rowdy',"age":null}}

See as_json.

Methods Range#as_json and Range.json_create may be used to serialize and deserialize a Range object; see Marshal.

Method Range#as_json serializes self, returning a 2-element hash representing self:

require 'json/add/range'
x = (1..4).as_json     # => {"json_class"=>"Range", "a"=>[1, 4, false]}
y = (1...4).as_json    # => {"json_class"=>"Range", "a"=>[1, 4, true]}
z = ('a'..'d').as_json # => {"json_class"=>"Range", "a"=>["a", "d", false]}

Method JSON.create deserializes such a hash, returning a Range object:

Range.json_create(x) # => 1..4
Range.json_create(y) # => 1...4
Range.json_create(z) # => "a".."d"

Returns a JSON string representing self:

require 'json/add/range'
puts (1..4).to_json
puts (1...4).to_json
puts ('a'..'d').to_json

Output:

{"json_class":"Range","a":[1,4,false]}
{"json_class":"Range","a":[1,4,true]}
{"json_class":"Range","a":["a","d",false]}

See as_json.

Methods Rational#as_json and Rational.json_create may be used to serialize and deserialize a Rational object; see Marshal.

Method Rational#as_json serializes self, returning a 2-element hash representing self:

require 'json/add/rational'
x = Rational(2, 3).as_json
# => {"json_class"=>"Rational", "n"=>2, "d"=>3}

Method JSON.create deserializes such a hash, returning a Rational object:

Rational.json_create(x)
# => (2/3)

Returns a JSON string representing self:

require 'json/add/rational'
puts Rational(2, 3).to_json

Output:

{"json_class":"Rational","n":2,"d":3}

See as_json.

Methods Regexp#as_json and Regexp.json_create may be used to serialize and deserialize a Regexp object; see Marshal.

Method Regexp#as_json serializes self, returning a 2-element hash representing self:

require 'json/add/regexp'
x = /foo/.as_json
# => {"json_class"=>"Regexp", "o"=>0, "s"=>"foo"}

Method JSON.create deserializes such a hash, returning a Regexp object:

Regexp.json_create(x) # => /foo/

Returns a JSON string representing self:

require 'json/add/regexp'
puts /foo/.to_json

Output:

{"json_class":"Regexp","o":0,"s":"foo"}

Returns object if it is a regexp:

Regexp.try_convert(/re/) # => /re/

Otherwise if object responds to :to_regexp, calls object.to_regexp and returns the result.

Returns nil if object does not respond to :to_regexp.

Regexp.try_convert('re') # => nil

Raises an exception unless object.to_regexp returns a regexp.

Returns true if matching against re can be done in linear time to the input string.

Regexp.linear_time?(/re/) # => true

Note that this is a property of the ruby interpreter, not of the argument regular expression. Identical regexp can or cannot run in linear time depending on your ruby binary. Neither forward nor backward compatibility is guaranteed about the return value of this method. Our current algorithm is (*1) but this is subject to change in the future. Alternative implementations can also behave differently. They might always return false for everything.

(*1): doi.org/10.1109/SP40001.2021.00032

See as_json.

Methods Set#as_json and Set.json_create may be used to serialize and deserialize a Set object; see Marshal.

Method Set#as_json serializes self, returning a 2-element hash representing self:

require 'json/add/set'
x = Set.new(%w/foo bar baz/).as_json
# => {"json_class"=>"Set", "a"=>["foo", "bar", "baz"]}

Method JSON.create deserializes such a hash, returning a Set object:

Set.json_create(x) # => #<Set: {"foo", "bar", "baz"}>

Returns a JSON string representing self:

require 'json/add/set'
puts Set.new(%w/foo bar baz/).to_json

Output:

{"json_class":"Set","a":["foo","bar","baz"]}

See as_json.

Methods Struct#as_json and Struct.json_create may be used to serialize and deserialize a Struct object; see Marshal.

Method Struct#as_json serializes self, returning a 2-element hash representing self:

require 'json/add/struct'
Customer = Struct.new('Customer', :name, :address, :zip)
x = Struct::Customer.new.as_json
# => {"json_class"=>"Struct::Customer", "v"=>[nil, nil, nil]}

Method JSON.create deserializes such a hash, returning a Struct object:

Struct::Customer.json_create(x)
# => #<struct Struct::Customer name=nil, address=nil, zip=nil>

Returns a JSON string representing self:

require 'json/add/struct'
Customer = Struct.new('Customer', :name, :address, :zip)
puts Struct::Customer.new.to_json

Output:

{"json_class":"Struct","t":{'name':'Rowdy',"age":null}}