Control Flow

Expressions

• Blocks have value

• Operator precedence table is in the reference manual. 18 levels. Left associativity. Left-to-right evaluation?

• Conversion is mostly explicit through as. Only conversions that are "safe" work (where safe has a somewhat non-intuitive definition)

• Reference magic happens

  • Auto dereference in certain situations as discussed earlier
  • Auto reference conversions in certain situations, e.g. String, Vec, Box

Expressions and Control Flow

• In Rust, some of what we would normally do with control flow is done with simple expressions. This is part of Rust's functional-language heritage

  • if is an expression type
  • "method" chaining is a standard mechanism

"Method" Chaining

• Many Rust operations are used in an "object-oriented style":

  "hello".to_uppercase()
  

  vs

  to_uppercase("hello")
  

• This allows stringing together expressions in more readable syntax (and also facilitates proper borrowing/sharing).

  https://play.rust-lang.org/?gist=fe8f51647a4cd3268c74e2276bef9089&version=undefined

Explicit Control Flow

• if-else

• if let, while let

• match

• while

• loop

• for and iterators