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class Object
# Invokes the public method identified by the symbol +method+, passing it any arguments
# and/or the block specified, just like the regular Ruby <tt>Object#public_send</tt> does.
#
# *Unlike* that method however, a +NoMethodError+ exception will *not* be raised
# and +nil+ will be returned instead, if the receiving object is a +nil+ object or NilClass.
#
# This is also true if the receiving object does not implemented the tried method. It will
# return +nil+ in that case as well.
#
# If try is called without a method to call, it will yield any given block with the object.
#
# Please also note that +try+ is defined on +Object+, therefore it won't work with
# subclasses of +BasicObject+. For example, using try with +SimpleDelegator+ will
# delegate +try+ to target instead of calling it on delegator itself.
#
# Without +try+
# @person && @person.name
# or
# @person ? @person.name : nil
#
# With +try+
# @person.try(:name)
#
# +try+ also accepts arguments and/or a block, for the method it is trying
# Person.try(:find, 1)
# @people.try(:collect) {|p| p.name}
#
# Without a method argument try will yield to the block unless the receiver is nil.
# @person.try { |p| "#{p.first_name} #{p.last_name}" }
#
# +try+ behaves like +Object#public_send+, unless called on +NilClass+.
def try(*a, &b)
if a.empty? && block_given?
yield self
else
public_send(*a, &b) if respond_to?(a.first)
end
end
# Same as #try, but will raise a NoMethodError exception if the receiving is not nil and
# does not implemented the tried method.
def try!(*a, &b)
if a.empty? && block_given?
yield self
else
public_send(*a, &b)
end
end
end
class NilClass
# Calling +try+ on +nil+ always returns +nil+.
# It becomes specially helpful when navigating through associations that may return +nil+.
#
# nil.try(:name) # => nil
#
# Without +try+
# @person && !@person.children.blank? && @person.children.first.name
#
# With +try+
# @person.try(:children).try(:first).try(:name)
def try(*args)
nil
end
def try!(*args)
nil
end
end
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