Pattern matching in scala

This presentation is a summary of pattern matching for a functional programing group ,at EAFIT university.

Transcript

1. Pattern Matching DEMO Pattern Matching Jesse Javier Cogollo Alvarez Developer by passion email: cogollo87@gmail.com Functional programming group September 9, 2015 1 / 17
2. Pattern Matching DEMO Content Pattern Matching DEMO 2 / 17
3. Pattern Matching DEMO what is Pattern Matching? Is the act of checking a given sequence of tokens for the presence of the constituens of some pattern. https://en.wikipedia.org/wiki/Pattern_matching 3 / 17
4. Pattern Matching DEMO characteristics • Useful Provide a powerful tool for declaring business logic in a concise and maintainable way. 4 / 17
5. Pattern Matching DEMO characteristics • Basic pattern matching Allow you to make a programmatic choice between multiple conditions. cases can include types, wildcards, sequences,regular expressions and so forth. 5 / 17
6. Pattern Matching DEMO characteristics • At its core Is a complex set of if/else expressions that lets you select from a number of alternatives. 6 / 17
7. Pattern Matching DEMO characteristics • Guard It is useful to test particular conditions that cannot be tested in the pattern declaration itselft. 7 / 17
8. Pattern Matching DEMO characteristics • Lists Pattern matching and Lists go hand in hand Are inmutable. Is implemented as a linked list where the head of the list is called a cons cell. cons cell is represented by the ::case class 8 / 17
9. Pattern Matching DEMO characteristics • case classes Case classes are classes that get to String, hashcode, and equal methods automatically. also can be constructed without using the new keyword. By default are read-only. and the case class is inmutable. 9 / 17
10. Pattern Matching DEMO characteristics • Nested Scala’s case classes give you a lot of flexibility for pattern matching, estracting values, nesting patterns, and so on. You can express a lot of logic in pattern declarations. 10 / 17
11. Pattern Matching DEMO characteristics • Pattern matching as functions Are syntactic elements of the language when used with the match operator. You can also pass pattern matching as a parameter to other methods. Pattern are functions and functions are instances, pattern are instances. 11 / 17
12. Pattern Matching DEMO characteristics • Shape abstractions Visitor pattern: It is a pattern that allows you to add functionality to a class hierarchy after the hierarchy is already defined. 12 / 17
13. Pattern Matching DEMO Summary • Provide powerful declarative syntax for expressing complex logic. • Provide a excellent and type-safe alternative to java’s test/cast paradigm. • Used with case class and extraction provide a powerful way to traverse object hierarchies. 13 / 17
14. Pattern Matching DEMO DEMO =) 14 / 17
15. Pattern Matching DEMO Resource Beginning Scala http://www.amazon.com/Beginning-Scala-Vishal-Layka/dp/1484202333 15 / 17
16. Pattern Matching DEMO Questions 16 / 17
17. Pattern Matching DEMO Thanks !!! =) 17 / 17