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Updated "while let" example. #30059

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Merged
merged 3 commits into from
Nov 29, 2015
Merged

Updated "while let" example. #30059

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b1c5c26
Updated "while let" example.
androm3da Nov 25, 2015
465a5cb
Corrections to the while-let example per review.
androm3da Nov 26, 2015
797a0bd
Shifted focus of while-let example per review.
androm3da Nov 27, 2015
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7 changes: 4 additions & 3 deletions src/doc/book/if-let.md
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Original file line number Diff line number Diff line change
Expand Up @@ -58,7 +58,7 @@ if let Some(x) = option {
## `while let`

In a similar fashion, `while let` can be used when you want to conditionally
loop as long as a value matches a certain pattern. It turns code like this:
loop as long as a value matches a certain pattern. It turns code like this:

```rust
# let option: Option<i32> = None;
Expand All @@ -73,8 +73,9 @@ loop {
Into code like this:
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"no sugar" version of the while let over v.pop() looks like

let mut v = vec![1, 3, 5, 7, 11];
loop {
    match v.pop() {
        Some(x) =>  println!("{}", x),
        None => break,
    }
}


```rust
# let option: Option<i32> = None;
while let Some(x) = option {
let v: vec![1, 3, 5, 7, 11, ];
let mut iter: v.iter();
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should be =, not : on these two lines.

But, why not show off something else than iterators since that's a good while let speciality? For example looping over the result of v.pop().

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let mut v = vec![1, 3, 5, 7, 11];
while let Some(x) = v.pop() {
    println!("{}", x);
}

while let Some(x) = iter.next() {
println!("{}", x);
}
```
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