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Chapter 6. Subroutine References

So far, you've seen references to arrays and hashes. You can also take a reference to a subroutine (sometimes called a coderef).

Why would you want to do that? Well, in the same way that taking a reference to an array lets you have the same code work on different arrays at different times, taking a reference to a subroutine allows the same code to call different subroutines at different times. Also, references permit complex data structures. A reference to a subroutine allows a subroutine to effectively become part of that complex data structure.

Put another way, a variable or a complex data structure is a repository of values throughout the program. A reference to a subroutine can be thought of as a repository of behavior in a program. The examples in this section show how this works.



    		Chapter 1. Introduction
    		Chapter 2. Building Larger Programs
    		Chapter 3. Introduction to References
    		Chapter 4. References and Scoping
    		Chapter 5. Manipulating Complex Data Structures
    		Chapter 6. Subroutine References
    		6.1 Referencing a Named Subroutine
    		6.2 Anonymous Subroutines
    		6.3 Callbacks
    		6.4 Closures
    		6.5 Returning a Subroutine from a Subroutine
    		6.6 Closure Variables as Inputs
    		6.7 Closure Variables as Static Local Variables
    		6.8 Exercise
    		Chapter 7. Practical Reference Tricks
    		Chapter 8. Introduction to Objects
    		Chapter 9. Objects with Data
    		Chapter 10. Object Destruction
    		Chapter 11. Some Advanced Object Topics
    		Chapter 12. Using Modules
    		Chapter 13. Writing a Distribution
    		Chapter 14. Essential Testing
    		Chapter 15. Contributing to CPAN
    		Appendix A. Answers to Exercises