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Advanced Features.md
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Any Number of Futures.md
Applying Async.md
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Cargo and Cratesio.md
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Closures.md
Collection of Common Data Structs.md
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Deref Trait.md
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For later baja.md
Futures and Async.md
Futures in Sequence.md
Futures, Tasks and Threads Together.md
Generic Types Traits and Lifetimes.md
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Hash.md
Implementing OO Design Pattern.md
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Iterators and Closures.md
Iterators.md
Leaky Reference Cycles.md
Lifetimes.md
Modules and Use.md
OOP Programming Features.md
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Passing Data Between Threads.md
Paths.md
Pattern Matching.md
Pattern Syntax.md
Places Patterns Can Be Used.md
Primitives.md
Project Organization.md
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README.md
Reducing_Code_Duplication.md
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44 lines
1.9 KiB
Markdown
44 lines
1.9 KiB
Markdown
# Patterns and Matching
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*Patterns* are a special syntax in Rust for matching against the structure of types, both complex and simple.
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Using patterns in conjunction with `match` expressions and other constructs give you more control over a program's flow.
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A pattern consists of some combination of the following:
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- Literals
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- Destructured arrays, enums, structs, or tuples
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- Variables
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- Wildcards
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- Placeholders
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Some examples include `x`, `(a, 3)` and `Some(Color::Red)`.
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In the contexts in which patterns are valid, these components describe the shape of data.
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Our program then matches values against the patterns to determine whether it has the correct shape of data to continue running a particular piece of code.
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In order to use a pattern, we compare it to some value.
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If the pattern matches the value, we use the value parts in our code.
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Recall the `match` expression that used patterns, such as the coin-sorting machine example.
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If the value fits the shape of the pattern, we can use the named pieces.
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If it doesn't, the code associated with the pattern won't run.
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This chapter is intended to be a reference on all things related to patterns.
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We will cover:
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- Valid places to use patterns [Section Link Here]()
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- Difference between refutable and irrefutable patterns [Section Link Here](./Refutability.md)
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- Different kinds of pattern syntax [Section Link Here](./Pattern%20Syntax.md)
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By the end you will know how to use patterns to express many concepts in a clear way.
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## Summary
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Patterns are very useful in distinguishing between different kinds of data.
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When used in `match` expressions, Rust ensures your patterns cover every possible value, or your program will not compile.
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Patterns in `let` statements and function parameters make those constructs more useful, enabling the destructuring of values into smaller parts at the same time as assigning to variables.
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Then we can create simple or complex patterns to suit our needs. |