Tools for each stage of compiler design have been designed that take in the specifications of the stage and output the compiler fragment of that stage. For example , lex is a popular tool for lexical analysis, yacc is a popular tool for syntactic analysis. Similarly, tools have been designed for each of these stages that take in specifications required for that phase e.g., the code generator tool takes in machine specifications and outputs the final compiler code. This design of having separate tools for each stage of compiler development has many advantages that have been described on the next slide.