method

block_given?

v1_8_7_330 - Show latest stable - 0 notes - Class: Kernel

block_given?() public

Returns true if yield would execute a block in the current context. The iterator? form is mildly deprecated.

def try
  if block_given?
    yield
  else
    "no block"
  end
end
try                  #=> "no block"
try { "hello" }      #=> "hello"
try do "hello" end   #=> "hello"

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/*
 *  call-seq:
 *     block_given?   => true or false
 *     iterator?      => true or false
 *  
 *  Returns <code>true</code> if <code>yield</code> would execute a
 *  block in the current context. The <code>iterator?</code> form
 *  is mildly deprecated.
 *     
 *     def try
 *       if block_given?
 *         yield
 *       else
 *         "no block"
 *       end
 *     end
 *     try                  #=> "no block"
 *     try { "hello" }      #=> "hello"
 *     try do "hello" end   #=> "hello"
 */


static VALUE
rb_f_block_given_p()
{
    if (ruby_frame->prev && ruby_frame->prev->iter == ITER_CUR && ruby_block)
        return Qtrue;
    return Qfalse;
}

block_given?

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