-
Notifications
You must be signed in to change notification settings - Fork 9
Commit
This commit does not belong to any branch on this repository, and may belong to a fork outside of the repository.
- Loading branch information
Showing
4 changed files
with
133 additions
and
31 deletions.
There are no files selected for viewing
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
Loading
Sorry, something went wrong. Reload?
Sorry, we cannot display this file.
Sorry, this file is invalid so it cannot be displayed.
Large diffs are not rendered by default.
Oops, something went wrong.
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,51 @@ | ||
| <Query Kind="Program" /> | ||
|
|
||
| // Sample from | ||
| // Real-World Functional Programming | ||
| // With examples in F# and C# | ||
| // Tomas Petricek with Jon Skeet | ||
| // http://www.manning.com/petricek/ | ||
|
|
||
| void Main() | ||
| { | ||
| ReadInput().Dump("Option<T> read from input"); | ||
| } | ||
|
|
||
| Option<int> ReadInput() { | ||
| string s = Util.ReadLine(); | ||
| int parsed; | ||
| if (Int32.TryParse(s, out parsed)) | ||
| return Option.Some(parsed); | ||
| else | ||
| return Option.None<int>(); | ||
| } | ||
|
|
||
| enum OptionType { Some, None }; | ||
| abstract class Option<T> { | ||
| private readonly OptionType tag; | ||
| protected Option(OptionType tag) { | ||
| this.tag = tag; | ||
| } | ||
| public OptionType Tag { get { return tag; } } | ||
| } | ||
|
|
||
| class None<T> : Option<T> { | ||
| public None() : base(OptionType.None) { } | ||
| } | ||
|
|
||
| class Some<T> : Option<T> { | ||
| public Some(T value) : base(OptionType.Some) { | ||
| this.value = value; | ||
| } | ||
| private readonly T value; | ||
| public T Value { get { return value; } } | ||
| } | ||
|
|
||
| static class Option { | ||
| public static Option<T> None<T>() { | ||
| return new None<T>(); | ||
| } | ||
| public static Option<T> Some<T>(T value) { | ||
| return new Some<T>(value); | ||
| } | ||
| } |