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revamps the RDoc of Object#try
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1 changed files with 33 additions and 25 deletions
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@ -1,35 +1,43 @@
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class Object
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# Invokes the public method identified by the symbol +method+, passing it any arguments
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# and/or the block specified, just like the regular Ruby <tt>Object#public_send</tt> does.
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# Invokes the public method whose name goes as first argument just like
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# +public_send+ does, except that if the receiver does not respond to it the
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# call returns +nil+ rather than raising an exception.
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#
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# *Unlike* that method however, a +NoMethodError+ exception will *not* be raised
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# and +nil+ will be returned instead, if the receiving object is a +nil+ object or NilClass.
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# This method is defined to be able to write
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#
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# This is also true if the receiving object does not implemented the tried method. It will
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# return +nil+ in that case as well.
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#
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# If try is called without a method to call, it will yield any given block with the object.
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#
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# Please also note that +try+ is defined on +Object+, therefore it won't work with
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# subclasses of +BasicObject+. For example, using try with +SimpleDelegator+ will
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# delegate +try+ to target instead of calling it on delegator itself.
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#
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# Without +try+
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# @person && @person.name
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# or
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# @person ? @person.name : nil
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#
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# With +try+
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# @person.try(:name)
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#
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# +try+ also accepts arguments and/or a block, for the method it is trying
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# Person.try(:find, 1)
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# @people.try(:collect) {|p| p.name}
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# instead of
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#
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# Without a method argument try will yield to the block unless the receiver is nil.
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# @person.try { |p| "#{p.first_name} #{p.last_name}" }
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# @person ? @person.name : nil
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#
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# +try+ behaves like +Object#public_send+, unless called on +NilClass+.
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# +try+ returns +nil+ when called on +nil+ regardless of whether it responds
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# to the method:
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#
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# nil.try(:to_i) # => nil, rather than 0
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#
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# Arguments and blocks are forwarded to the method if invoked:
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#
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# @posts.try(:each_slice, 2) do |a, b|
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# ...
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# end
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#
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# The number of arguments in the signature must match. If the object responds
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# to the method the call is attempted and +ArgumentError+ is still raised
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# otherwise.
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#
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# If +try+ is called without arguments it yields the receiver to a given
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# block unless it is +nil+:
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#
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# @person.try do |p|
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# ...
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# end
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#
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# Please also note that +try+ is defined on +Object+, therefore it won't work
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# with instances of classes that do not have +Object+ among their ancestors,
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# like direct subclasses of +BasicObject+. For example, using +try+ with
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# +SimpleDelegator+ will delegate +try+ to the target instead of calling it on
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# delegator itself.
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def try(*a, &b)
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if a.empty? && block_given?
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yield self
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