Ruby, another programming language inspired by Perl, can be made to support this syntax too:

# set local variables at the top level of a file
cout = $stdout
endl = "\n"

cout << "Whatever" << endl;

# equivalents:
$stdout.write("Whatever"); $stdout.write("\n")
# or
$stdout.puts("Whatever")
# or
puts "Whatever" # because the method Kernel#puts calls `$stdout.puts(*args)`

Or, if you want to this syntax to be usable in multiple files:

module CPlusPlusConstants
  def cout
    $stdout
  end

  def endl
    "\n"
  end
end

# in another file in the directory
require_relative 'cpp_constants.rb'
include CPlusPlusConstants
cout << "Whatever" << endl;

In Ruby, methods can be called without parentheses, so methods with no parameters that are in scope act just like a Raku “term” as described in this post. In the above code, the Module#include method brings the methods cout and endl into the file’s implicit top-level module.

Ruby’s IO class already defines a << instance method that backs the << operator, but you could always redefine it, as Ruby’s classes are open for modification:

class IO
  def <<(value)
    write(value) # calls IO#write
    self
  end
end