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Cargo.toml

Add dependencies with Cargo.toml.

Cargo.toml

Cargo.toml defines the package's identity and dependencies. It's in TOML format: [section] headers and key = value lines:

[package]
name = "fatura"
version = "0.1.0"
edition = "2021"

[dependencies]
serde = { version = "1", features = ["derive"] }
rand = "0.8"

[dev-dependencies]
pretty_assertions = "1"

edition decides which edition's rules the language is compiled with (2015, 2018, 2021, 2024); crates on different editions work together.

Cargo.lock

Cargo.lock records the exact version of every resolved dependency, so everyone gets the same build. In binary projects it's committed to version control. cargo update moves to the newest versions within the allowed range, and cargo add serde adds a dependency to Cargo.toml.

$ cargo add rand
$ cargo tree        # dependency tree
$ cargo update -p rand

Practice Read a TOML line

Split the text let girdi = "edition = \"2021\""; with split_once('='), trim both sides and remove the quotes from the value with trim_matches('"'). Print it as edition: 2021.

Starter code

main.rs
fn main() {
    // buraya yaz
}

Sample solution

main.rs
fn main() {
    let girdi = "edition = \"2021\"";
    let (anahtar, deger) = girdi.split_once('=').unwrap();
    let anahtar = anahtar.trim();
    let deger = deger.trim().trim_matches('"');
    println!("{}: {}", anahtar, deger);
}

Expected output

edition: 2021

Questions and answers

Review the lesson questions together with their answers. To test yourself, solve the lesson interactively.

1 When are dependencies under <code>[dev-dependencies]</code> compiled?

  • In every build
  • Only in a release build
  • Never
  • Only for tests, examples and benchmarks Correct answer

Explanation: Users of the library don't download dev-dependencies; ideal for test tools.

2 Dependency section

Question 
[____]
rand = "0.8"
Answer 
[dependencies]
rand = "0.8"

Explanation: Runtime dependencies go under [dependencies].

3 Key and meaning

Term Meaning
name Package name
version Package version
edition Language edition rules
[dev-dependencies] Test dependencies

All lessons in Intermediate

1 Traits

  1. What is a trait?
  2. Implementing a trait
  3. Default methods
  4. Traits as parameters
  5. Multiple traits
  6. Summary - Traits

2 Generics

  1. Generic function
  2. Generic struct
  3. Generic method
  4. Generic enum
  5. Turbofish
  6. Summary - Generics

3 Lifetimes

  1. What is a lifetime?
  2. Explicit lifetimes
  3. Function lifetimes
  4. Struct lifetimes
  5. Elision rules
  6. Summary - Lifetimes

4 Trait bounds

  1. Trait bound
  2. Multiple bounds
  3. where clause
  4. impl Trait
  5. dyn Trait
  6. Summary - Trait bounds

5 Project: Library crate

  1. Crate skeleton
  2. Public API
  3. Generic structure
  4. Searching with traits
  5. Test infrastructure

6 Smart pointers

  1. Box<T>
  2. Rc<T>
  3. Arc<T>
  4. Box and recursion
  5. Deref
  6. Summary - Smart pointers

7 Interior mutability

  1. RefCell<T>
  2. borrow and borrow_mut
  3. Rc<RefCell<T>>
  4. Cell<T>
  5. External mutation
  6. Summary - Interior mutability

8 Closures

  1. Closure syntax
  2. Type inference
  3. Capturing
  4. Fn, FnMut, FnOnce
  5. Closure and iterator
  6. Summary - Closures

9 Iterators

  1. Iterator trait
  2. next method
  3. map and filter
  4. collect
  5. Lazy evaluation
  6. Summary - Iterators

10 Collections

  1. HashMap
  2. BTreeMap
  3. HashSet
  4. Entry API
  5. Iterating collections
  6. Summary - Collections

11 Project: CLI app

  1. Command skeleton
  2. State with Vec
  3. Result and commands
  4. Processing with iterators
  5. Error and exit

12 Advanced error handling

  1. Error trait
  2. thiserror
  3. anyhow
  4. Error conversion
  5. Adding context
  6. Summary - Advanced error handling

13 Modules

  1. Defining modules
  2. use
  3. pub
  4. File modules
  5. crate and super
  6. Summary - Modules

14 Crates and packages

  1. Binary and library crate
  2. Cargo.toml
  3. Versions
  4. Features
  5. Workspace
  6. Summary - Crates and packages

15 Testing

  1. Unit test
  2. assert! macro
  3. Integration test
  4. Doc test
  5. should_panic
  6. Summary - Testing

16 File I/O

  1. Reading a file
  2. Writing a file
  3. Append mode
  4. BufReader
  5. Directory operations
  6. Summary - File I/O

17 CLI with clap

  1. Introducing clap
  2. Derive macro
  3. Positional argument
  4. Option flag
  5. Subcommand
  6. Summary - CLI with clap

18 Serialization with serde

  1. Serialize and Deserialize
  2. derive
  3. JSON
  4. Field rename
  5. Option and default
  6. Summary - Serde

19 Project: Blog API

  1. Model skeleton
  2. Reading JSON
  3. Error handling
  4. Listing records
  5. CLI

20 Intermediate final

  1. Generic stack
  2. Shapes with traits
  3. Iterator adapter
  4. JSON config reader