Don't try to replace self in a macro expansion since it's unlikely to be the desired behavior. A more explicit means of specifying what variables should be replaced in a quote expression is needed.

#{
	main <- {
		sock <- socket connectTo: "127.0.0.1" onPort: 12345
		sock send: "Hello, Socket!\n"
		response <- sock recv: 1024
		print: (string: response)
		sock close
		0
	}
}