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* Speaker notes for pattern matching * Update pattern-matching.md Co-authored-by: Fabian Bornhofen <fbornhofen@google.com>
36 lines
1.2 KiB
Markdown
36 lines
1.2 KiB
Markdown
# Pattern Matching
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The `match` keyword let you match a value against one or more _patterns_. The
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comparisons are done from top to bottom and the first match wins.
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The patterns can be simple values, similarly to `switch` in C and C++:
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```rust,editable
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fn main() {
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let input = 'x';
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match input {
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'q' => println!("Quitting"),
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'a' | 's' | 'w' | 'd' => println!("Moving around"),
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'0'..='9' => println!("Number input"),
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_ => println!("Something else"),
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}
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}
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```
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The `_` pattern is a wildcard pattern which matches any value.
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<details>
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Key Points:
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* You might point out how some specific characters are being used when in a patten
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* `|` as an `or`
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* `..` can expand as much as it needs to be
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* `1..=5` represents an inclusive range
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* `_` is a wild card
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* It can be useful to show how binding works, by for instance replacing a wildcard character with a variable, or removing the quotes around `q`.
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* You can demonstrate matching on a reference.
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* This might be a good time to bring up the concept of irrefutable patterns, as the term can show up in error messages.
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</details>
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