class<\/span> RunOnceProc<\/span> <<\/span> Proc<\/span>\n class<\/span> MultipleCallAttempt<\/span> <<\/span> StandardError<\/span>;<\/span> end<\/span>\n \n def<\/span> call<\/span>(<\/span>*<\/span>args<\/span>)<\/span>\n raise<\/span>(<\/span>MultipleCallAttempt<\/span>,<\/span> "You cannot call this proc more than once"<\/span>)<\/span> if<\/span> called?<\/span>\n @_called<\/span> =<\/span> true<\/span>\n super<\/span>\n end<\/span>\n \n def<\/span> called?<\/span>\n !!<\/span>@_called<\/span>\n end<\/span>\n \nend<\/span>\n\np<\/span> =<\/span> RunOnceProc<\/span>.<\/span>new<\/span> {<\/span>|<\/span>name<\/span>|<\/span> puts<\/span> "hi <\/span>#{<\/span>name<\/span>}<\/span>"<\/span>}<\/span>\n\np<\/span>.<\/span>call<\/span>(<\/span>"John"<\/span>)<\/span> # => hi John<\/span>\np<\/span>.<\/span>call<\/span>(<\/span>"Paul"<\/span>)<\/span> # => RunOnceProc:: MultipleCallAttempt: You cannot call this proc more than once<\/span>\n<\/pre><\/div>\n');
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