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Merge pull request #185 from markozagar/zagar
Edits to Day1 Morning material
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@ -26,16 +26,21 @@ fn main() {
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```
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```
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<details>
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<details>
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Key points:
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Key points:
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Arrays:
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Arrays:
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* Arrays have elements of the same type, `T`, and length, `N`, which is a compile-time constant.
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* Arrays have elements of the same type, `T`, and length, `N`, which is a compile-time constant.
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Note that the length of the array is *part of its type*, which means that `[u8; 3]` and
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`[u8; 4]` are considered two different types.
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* We can use literals to assign values to arrays.
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* We can use literals to assign values to arrays.
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* In the main function, the print statement asks for the debug implementation with the `?` format parameter: `{a}` gives the default output, `{a:?}` gives the debug output.
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* In the main function, the print statement asks for the debug implementation with the `?` format
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parameter: `{}` gives the default output, `{:?}` gives the debug output. We
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could also have used `{a}` and `{a:?}` without specifying the value after the
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format string.
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* Adding `#`, eg `{a:#?}`, invokes a "pretty printing" format, which can be easier to read.
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* Adding `#`, eg `{a:#?}`, invokes a "pretty printing" format, which can be easier to read.
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@ -45,6 +50,11 @@ Tuples:
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* Tuples group together values of different types into a compound type.
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* Tuples group together values of different types into a compound type.
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* Fields that can be accessed by the period and the index of the value, e.g. `t.0`, `t.1`.
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* Fields of a tuple can be accessed by the period and the index of the value, e.g. `t.0`, `t.1`.
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* The empty tuple `()` is also known as the "unit type". It is both a type, and
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the only valid value of that type - that is to say both the type and its value
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are expressed as `()`. It is used to indicate, for example, that a function or
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expression has no return value, as we'll see in a future slide.
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</details>
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</details>
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@ -11,9 +11,18 @@ fn main() {
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}
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}
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```
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```
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Some differences from C++:
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Some notes:
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* We must dereference `ref_x` when assigning to it, similar to C pointers,
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* We must dereference `ref_x` when assigning to it, similar to C and C++ pointers.
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* Rust will auto-dereference in some cases, in particular when invoking
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* Rust will auto-dereference in some cases, in particular when invoking
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methods (try `count_ones`).
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methods (try `ref_x.count_ones()`).
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* References that are declared as `mut` can be bound to different values over their lifetime.
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* References that are declared as `mut` can be bound to different values over their lifetime.
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<details>
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Key points:
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* Be sure to note the difference between `let mut ref_x: &i32` and `let ref_x:
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&mut i32`. The first one represents a mutable reference which can be bound to
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different values, while the second represents a reference to a mutable value.
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</details>
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@ -7,6 +7,7 @@ Rust is built with all the experience gained in the last 40 years.
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* Enums and pattern matching.
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* Enums and pattern matching.
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* Generics.
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* Generics.
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* No overhead FFI.
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* No overhead FFI.
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* Zero-cost abstractions.
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## Tooling
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## Tooling
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@ -18,6 +19,15 @@ Rust is built with all the experience gained in the last 40 years.
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Key points:
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Key points:
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* Zero-cost abstractions, similar to C++, means that you don't have to 'pay'
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for higher-level programming constructs with memory or CPU. For example,
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writing a loop using `for` should result in roughly the same low level
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instructions as using the `.iter().fold()` construct.
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* It may be worth mentioning that Rust enums are 'Algebraic Data Types', also
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known as 'sum types', which allow the type system to express things like
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`Option<T>` and `Result<T, E>`.
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* Remind people to read the errors --- many developers have gotten used to
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* Remind people to read the errors --- many developers have gotten used to
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ignore lengthly compiler output. The Rust compiler is significantly more
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ignore lengthly compiler output. The Rust compiler is significantly more
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talkative than other compilers. It will often provide you with _actionable_
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talkative than other compilers. It will often provide you with _actionable_
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