Ruby異常

#!/usr/bin/ruby
# -*- coding: UTF-8 -*-

# Ruby   
    # =>              .              ,             ,         ...
    # =>       ,      .              ,                ,           ,            . 
    # => Ruby                .       begin/end              ,     rescue      Ruby         .

# =>   begin   rescue          .              ,       rescue   end     . 

#begin #   

#raise .. #     

# =>    begin       rescue   , Ruby                  . 
# =>    rescue                     ,          ,      .
# =>                 ,          rescue         else   .
#rescue [ExceptionType = StandardException] #                StandardException
#$! #       
#$@ #            
#else #         
#..
#ensure #        ,      

#end #   


#begin 
#   file = open("unexistant_file")
#   if file 
#       puts "File opened successfully"
#   end
#
#rescue
#   file = STDIN
#end

#print file, "==", STDIN, "
"

#    retry   
    # =>       rescue      ,      retry           begin  .
    # =>    retry,       
#begin
    # =>            rescue     
#rescue
    # =>              
#   retry # =>         begin   
#end


#    raise   
    # =>      raise       .              .            
    
#raise  # =>                (            RuntimeError).                        .
#  
#raise "Error Message" # =>            RuntimeError   ,              .             .
#  
#raise ExceptionType, "Error Message" # =>                  ,                .
# 
#raise ExceptionType, "Error Message" condition # =>          ,               (   unless)     .

#begin
#   puts 'I am before the raise'
#   raise 'An error has occurred' # =>     
#   puts 'I am after the raise'
#rescue
#   puts 'I am rescued.'    # => exe block
#end

#puts 'I am afrer the begin block'


#    ensure   
    # =>    ,         ,                    .   ,                ,      ,           .
    # => ensure         . ensure        rescue    ,                  . 
    # => ensure        .          ,          ,               ,        .
#begin
    #..   
    #..     
#rescue
    #..     
#ensure
    #..       
    #..       
#end


#begin 
#   raise 'A test exception' # =>       
#rescue Exception => e
#   puts e.message
#   puts e.backtrace.inspect
#ensure
#   puts "Ensuring execution"
#end

#    else   
    # => Ruby     else   ,        rescue     ,    ensure   .
    # => else                      .
#begin 
    #..   
    #..     
#rescue
    #..     
#else
    #..          
#ensure
    #..         
    #..      
#end

#begin
#   puts 'I am not raising exception'
#rescue Exception => e
#   puts e.message
#   puts e.backtrace.inspect
#else
#   puts 'Congratulations -- no errors!'
#ensure
#   puts 'Ensuring execution'
#end



# Catch   Throw
    # => raise   rescue                 ,                       .    catch   throw       . 
    # => catch             (    Symbol   String)       .              throw.
#throw :lablename
    #..      
#catch :lablename do 
    # =>       throw          catch
#end

# 

#throw :lablename condition
    #..       
#catch :lablename do
    #..       throw          catch
#end

#def promptAndGet(prompt)
#   print prompt
#   res = readline.chomp
#   throw :quitRequested if prompt == '!'
#   return res
#end


#catch :quitRequested do 
#   name = promptAndGet("Name: ")
#   age = promptAndGet("Age: ")
#   sex = promptAndGet("Sex: ")
    #.. 
    #     
#end

#promptAndGet("Name: ")



#   Exception
    # => Ruby            .             ,       Exception    .            :
        # => Interrupt 
        # => NoMemoryError
        # => SignalException
        # => ScriptError
        # => StandardError
        # => SystemExit
    # => Fatal           ,    Ruby           .
    # => ScriptError   Standard       .                 .
    # =>                ,        Exception        .

#class FileSaveError < StandardError
#   attr_reader :reason
#   def initialize(reason)
#       @reason = reason
#   end
#end


#File.open("test", "w") do |file|
#begin
    #      ..
#rescue
    #     
#   raise FileSaveError.new($!)
#end
#end