ruby/kernel.rb

175 строки
5.0 KiB
Ruby

module Kernel
#
# call-seq:
# obj.class -> class
#
# Returns the class of <i>obj</i>. This method must always be called
# with an explicit receiver, as #class is also a reserved word in
# Ruby.
#
# 1.class #=> Integer
# self.class #=> Object
#--
# Equivalent to \c Object\#class in Ruby.
#
# Returns the class of \c obj, skipping singleton classes or module inclusions.
#++
#
def class
Primitive.attr! 'inline'
Primitive.cexpr! 'rb_obj_class(self)'
end
#
# call-seq:
# obj.clone(freeze: nil) -> an_object
#
# Produces a shallow copy of <i>obj</i>---the instance variables of
# <i>obj</i> are copied, but not the objects they reference.
# #clone copies the frozen value state of <i>obj</i>, unless the
# +:freeze+ keyword argument is given with a false or true value.
# See also the discussion under Object#dup.
#
# class Klass
# attr_accessor :str
# end
# s1 = Klass.new #=> #<Klass:0x401b3a38>
# s1.str = "Hello" #=> "Hello"
# s2 = s1.clone #=> #<Klass:0x401b3998 @str="Hello">
# s2.str[1,4] = "i" #=> "i"
# s1.inspect #=> "#<Klass:0x401b3a38 @str=\"Hi\">"
# s2.inspect #=> "#<Klass:0x401b3998 @str=\"Hi\">"
#
# This method may have class-specific behavior. If so, that
# behavior will be documented under the #+initialize_copy+ method of
# the class.
#
def clone(freeze: nil)
Primitive.rb_obj_clone2(freeze)
end
#
# call-seq:
# obj.frozen? -> true or false
#
# Returns the freeze status of <i>obj</i>.
#
# a = [ "a", "b", "c" ]
# a.freeze #=> ["a", "b", "c"]
# a.frozen? #=> true
#--
# Determines if the object is frozen. Equivalent to \c Object\#frozen? in Ruby.
# \param[in] obj the object to be determines
# \retval Qtrue if frozen
# \retval Qfalse if not frozen
#++
#
def frozen?
Primitive.attr! 'inline'
Primitive.cexpr! 'rb_obj_frozen_p(self)'
end
#
# call-seq:
# obj.tap {|x| block } -> obj
#
# Yields self to the block, and then returns self.
# The primary purpose of this method is to "tap into" a method chain,
# in order to perform operations on intermediate results within the chain.
#
# (1..10) .tap {|x| puts "original: #{x}" }
# .to_a .tap {|x| puts "array: #{x}" }
# .select {|x| x.even? } .tap {|x| puts "evens: #{x}" }
# .map {|x| x*x } .tap {|x| puts "squares: #{x}" }
#
#--
# \private
#++
#
def tap
yield(self)
self
end
#
# call-seq:
# obj.then {|x| block } -> an_object
#
# Yields self to the block and returns the result of the block.
#
# 3.next.then {|x| x**x }.to_s #=> "256"
#
# Good usage for +then+ is value piping in method chains:
#
# require 'open-uri'
# require 'json'
#
# construct_url(arguments).
# then {|url| open(url).read }.
# then {|response| JSON.parse(response) }
#
# When called without block, the method returns +Enumerator+,
# which can be used, for example, for conditional
# circuit-breaking:
#
# # meets condition, no-op
# 1.then.detect(&:odd?) # => 1
# # does not meet condition, drop value
# 2.then.detect(&:odd?) # => nil
#
def then
unless Primitive.block_given_p
return Primitive.cexpr! 'SIZED_ENUMERATOR(self, 0, 0, rb_obj_size)'
end
yield(self)
end
#
# call-seq:
# obj.yield_self {|x| block } -> an_object
#
# Yields self to the block and returns the result of the block.
#
# "my string".yield_self {|s| s.upcase } #=> "MY STRING"
#
# Good usage for +then+ is value piping in method chains:
#
# require 'open-uri'
# require 'json'
#
# construct_url(arguments).
# then {|url| open(url).read }.
# then {|response| JSON.parse(response) }
#
def yield_self
unless Primitive.block_given_p
return Primitive.cexpr! 'SIZED_ENUMERATOR(self, 0, 0, rb_obj_size)'
end
yield(self)
end
module_function
#
# call-seq:
# Float(arg, exception: true) -> float or nil
#
# Returns <i>arg</i> converted to a float. Numeric types are
# converted directly, and with exception to String and
# <code>nil</code> the rest are converted using
# <i>arg</i><code>.to_f</code>. Converting a String with invalid
# characters will result in a ArgumentError. Converting
# <code>nil</code> generates a TypeError. Exceptions can be
# suppressed by passing <code>exception: false</code>.
#
# Float(1) #=> 1.0
# Float("123.456") #=> 123.456
# Float("123.0_badstring") #=> ArgumentError: invalid value for Float(): "123.0_badstring"
# Float(nil) #=> TypeError: can't convert nil into Float
# Float("123.0_badstring", exception: false) #=> nil
#
def Float(arg, exception: true)
Primitive.rb_f_float(arg, exception)
end
end