class Object

Returns another string that may be modified without touching the original object. This means dup for a string and to_s for any other object.

If a block is given, that may modify a created string (built from a non-string object). For a dup'ed string object the block will not be called.

VALUE
rb_obj_new_string( VALUE obj)
{
    VALUE r;

    r = rb_obj_as_string( obj);
    if (rb_block_given_p())
        rb_yield( r);
    return r;
}

Returns nil when the string matches val. val is compared using the === operator, just like in the case statement.

"hello".nil_if "NONE"      #=> "hello"
"NONE".nil_if "NONE"       #=> nil
"NONE".nil_if /^none$/i    #=> nil

20.nil_if 10      #=> 20
10.nil_if 10      #=> nil
1.0.nil_if Float  #=> nil

VALUE
rb_obj_nil_if( VALUE obj, VALUE val)
{
    if (!id_eqq)
        id_eqq = rb_intern( "===");
    return RTEST( rb_funcall( val, id_eqq, 1, obj)) ? Qnil : obj;
}

Yields x to the block, and then returns x. The primary purpose of this method is to “tap into” a method chain, in order to perform operations on intermediate results within the chain.

(1..10)                  .tap { |x| puts "original: #{x.inspect}" }
  .to_a                  .tap { |x| puts "array:    #{x.inspect}" }
  .select { |x| x%2==0 } .tap { |x| puts "evens:    #{x.inspect}" }
  .map { |x| x*x }       .tap { |x| puts "squares:  #{x.inspect}" }

VALUE
rb_krn_tap( VALUE obj)
{
    rb_yield( obj);
    return obj;
}

Yields x to the block, and then returns x if and only if x is not nil.

VALUE
rb_krn_tap_bang( VALUE obj)
{
    if (!NIL_P( obj))
      rb_yield( obj);
    return obj;
}