You are previewing Programming F# 3.0, 2nd Edition.

Programming F# 3.0, 2nd Edition

Cover of Programming F# 3.0, 2nd Edition by Chris Smith Published by O'Reilly Media, Inc.
  1. Programming F# 3.0
  2. Preface
    1. Introducing F#
    2. Who This Book Is For
    3. What You Need to Get Going
    4. How the Book Is Organized
      1. Part I
      2. Part II
      3. Part III
    5. Part IV
    6. Conventions Used in This Book
    7. Using Code Examples
    8. Safari® Books Online
    9. I’d Like to Hear from You
    10. Acknowledgments
  3. I. Multiparadigm Programming
    1. 1. Introduction to F#
      1. Getting to Know F#
      2. Visual Studio 11
      3. F# Interactive
      4. Managing F# Source Files
    2. 2. Fundamentals
      1. Primitive Types
      2. Comparison and Equality
      3. Functions
      4. Core Types
      5. Organizing F# Code
    3. 3. Functional Programming
      1. Understanding Functions
      2. Pattern Matching
      3. Discriminated Unions
      4. Records
      5. Lazy Evaluation
      6. Sequences
      7. Queries
    4. 4. Imperative Programming
      1. Understanding Memory in .NET
      2. Changing Values
      3. Units of Measure
      4. Arrays
      5. Mutable Collection Types
      6. Looping Constructs
      7. Exceptions
    5. 5. Object-Oriented Programming
      1. Programming with Objects
      2. Understanding System.Object
      3. Understanding Classes
      4. Methods and Properties
      5. Inheritance
    6. 6. .NET Programming
      1. The .NET Platform
      2. Interfaces
      3. Object Expressions
      4. Extension Methods
      5. Extending Modules
      6. Enumerations
      7. Structs
  4. II. Programming F#
    1. 7. Applied Functional Programming
      1. Active Patterns
      2. Using Modules
      3. Mastering Lists
      4. Tail Recursion
      5. Programming with Functions
      6. Functional Patterns
      7. Functional Data Structures
    2. 8. Applied Object-Oriented Programming
      1. Operators
      2. Generic Type Constraints
      3. Delegates and Events
      4. Events
    3. 9. Asynchronous and Parallel Programming
      1. Working with Threads
      2. Asynchronous Programming
      3. Asynchronous Workflows
      4. Parallel Programming
      5. Task Parallel Library
    4. 10. Scripting
      1. F# Script Files
      2. Directives
      3. F# Script Recipes
    5. 11. Data Processing
      1. Indexing
      2. Querying
  5. III. Extending the F# Language
    1. 12. Reflection
      1. Attributes
      2. Type Reflection
      3. Dynamic Instantiation
      4. Using Reflection
    2. 13. Computation Expressions
      1. Toward Computation Expressions
      2. Computation Expression Builders
      3. Custom Computation Expression Builders
    3. 14. Quotations
      1. Quotation Basics
      2. Generating Quotation Expressions
    4. 15. Type Providers
      1. Typed Data Versus Typed Languages
      2. Type Providers
  6. IV. Appendixes
    1. A. Overview of .NET Libraries
      1. Visualization
      2. Data Processing
      3. Storing Data
    2. B. F# Interop
      1. .NET Interop
      2. Unmanaged Interop
  7. Index
  8. About the Author
  9. Colophon
  10. Copyright
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Chapter 3. Functional Programming

With the basics out of the way, you can begin to examine F# from the approach of a particular style. This chapter is devoted to F#’s main paradigm: functional programming. In a nutshell, functional programming is about being more declarative in your code. In imperative programming (which we cover in Chapter 4), you spend your time listing out the specific steps to perform a task. In functional programming, you specify what is to be done, but not how. Even though functional programming is no silver bullet, the result is that programs are much clearer, and some problems—like concurrency and parallel programming—are made much easier.

Functional programming isn’t going to replace imperative or object-oriented programming on its own; rather, it just provides a different approach to use so that in certain applications you can be much more productive.

For a language to be considered “functional,” it typically needs to support a few key features:

  • Immutable data

  • Ability to compose functions

  • Functions can be treated as data

  • Lazy evaluation

  • Pattern matching

We go into each of these raw, functional concepts and what they offer throughout the chapter. By the end, you will be able to write purely functional code, and leverage the elegance and simplicity of declarative programming. A deeper look at functional concepts, such as tail recursion and closures, comes later in Chapter 7.

Understanding Functions

The heart of functional programming is thinking about code in terms ...

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