Datatypes, etc

Rust Playground

https://play.rust-lang.org/

Writing Programs

• Programs look a lot like any imperative language

• Can't have mutable global variables (kind of)

• Assignment is done with let statement, needn't provide types (static type inference)

• Types must agree completely, conversions are explicit with as

• Blocks must be bracketed. (Brackets and parens are kind of interchangeable)

• Semicolon is statement separator; optional null statements and expressions (comma)

• Last expression in block is value of that block

• If statement is ternary expression

• Fairly normal-looking while and for

• match is switch equivalent

Rust Datatypes

• Emphasis on safe, efficient, simple

• Type system borrows heavily from all the other parametric/template type systems out there

• "Borrow checker" tangled in with the type system statically checks lifetimes

Fundamental Datatypes

• Unit type: ()

• Boolean type: bool (true, false)

• Integer types:

  • i8, u8, i16, u16, i32, u32, i64, u64, i128, u128
  • isize, usize

• Floating types: f32, f64

• Character type: char

  • 32-bit Unicode code point
  • Conversion-to implies checking: from_u32 vs from_u32_unchecked
  • Strings are UTF-8, so not chars

• These types can be copied implicitly

• Numeric literals can have type suffix e.g. 0u64

Tuples

• Tuple types e.g. (u8,char,f64)

• Fixed number of values of diverse type

    (u64, f64, char)
  

  with obvious value representation

    let t = (12, 1.2, 'x');
  

• Great for e.g. multiple return values, points

• Copyable if elements are

• Pattern-matching syntax

• Accessible by dot-index