Method: Kernel#trap_chain

Defined in:
lib/core/facets/kernel/trap_chain.rb

#trap_chain(signal_name, *args, &block) ⇒ Object

Calling Kernel#trap() by itself will replace any previously registered handler code. Kernel#trap_chain(), on the other hand, will add the block you supply to the existing “list” of registered handler blocks. Similar to the way Kernel#at_exit() works, Kernel#trap_chain() will prepend the given block to the call chain for the given signal_name. When the signal occurs, your block will be executed first and then the previously registered handler will be invoked. This can be called repeatedly to create a “chain” of handlers.

NOTE: This method is not a common core extension and is not loaded automatically when using require 'facets'.

CREDIT: Tyler Rick

Uncommon:

  • require ‘facets/kernel/trap_chain’



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# File 'lib/core/facets/kernel/trap_chain.rb', line 19

def trap_chain(signal_name, *args, &block)
  previous_interrupt_handler = trap(signal_name, *args) {}
  trap(signal_name, *args) do
    block.call
    previous_interrupt_handler.call unless previous_interrupt_handler == "DEFAULT"
  end
end