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Improved example code in Option

This commit is contained in:
Adolfo Ochagavía 2014-05-11 18:23:46 +02:00 committed by Alex Crichton
parent 437338ab65
commit 85e34b2396
2 changed files with 30 additions and 24 deletions
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27
src/libcore/option.rs
View File

@ -30,20 +30,23 @@
//! of a value and take action, always accounting for the `None` case.
//!
//! ```
//! # // FIXME This is not the greatest first example
//! // cow_says contains the word "moo"
//! let cow_says = Some("moo");
//! // dog_says does not contain a value
//! let dog_says: Option<&str> = None;
//! fn divide(numerator: f64, denominator: f64) -> Option<f64> {
//! if denominator == 0.0 {
//! None
//! } else {
//! Some(numerator / denominator)
//! }
//! }
//!
//! // The return value of the function is an option
//! let result = divide(2.0, 3.0);
//!
//! // Pattern match to retrieve the value
//! match (cow_says, dog_says) {
//! (Some(cow_words), Some(dog_words)) => {
//! println!("Cow says {} and dog says {}!", cow_words, dog_words);
//! }
//! (Some(cow_words), None) => println!("Cow says {}", cow_words),
//! (None, Some(dog_words)) => println!("Dog says {}", dog_words),
//! (None, None) => println!("Cow and dog are suspiciously silent")
//! match result {
//! // The division was valid
//! Some(x) => println!("Result: {}", x),
//! // The division was invalid
//! None => println!("Cannot divide by 0")
//! }
//! ```
//!

27
src/libstd/option.rs
View File

@ -30,20 +30,23 @@
//! of a value and take action, always accounting for the `None` case.
//!
//! ```
//! # // FIXME This is not the greatest first example
//! // cow_says contains the word "moo"
//! let cow_says = Some("moo");
//! // dog_says does not contain a value
//! let dog_says: Option<&str> = None;
//! fn divide(numerator: f64, denominator: f64) -> Option<f64> {
//! if denominator == 0.0 {
//! None
//! } else {
//! Some(numerator / denominator)
//! }
//! }
//!
//! // The return value of the function is an option
//! let result = divide(2.0, 3.0);
//!
//! // Pattern match to retrieve the value
//! match (cow_says, dog_says) {
//! (Some(cow_words), Some(dog_words)) => {
//! println!("Cow says {} and dog says {}!", cow_words, dog_words);
//! }
//! (Some(cow_words), None) => println!("Cow says {}", cow_words),
//! (None, Some(dog_words)) => println!("Dog says {}", dog_words),
//! (None, None) => println!("Cow and dog are suspiciously silent")
//! match result {
//! // The division was valid
//! Some(x) => println!("Result: {}", x),
//! // The division was invalid
//! None => println!("Cannot divide by 0")
//! }
//! ```
//!