Methods on built-ins

Hashmap

  • .entry — Used for in-place manipulation of the value for a corresponding key, scores.entry(team_id)
  • .or_default — Insert an empty default value if the key is not present, returning a mutable reference, scores.entry(team_id).or_default()
  • .or_insert — Insert a populated default value if the key is not present, also returning a mutable reference, sat_scores.entry(student_id).or_insert(400)

String slice

  • .len — Get the length of the string slice, name.len()
  • .is_empty — Check if the string slice is empty, name.is_empty()
  • .to_string — Convert a string slice to a String, name.to_string(); compare, contrast with String::from

Keywords

Variable Bindings and Data Declaration

  • let — Declare a variable
  • const — Declare a compile-time constant
  • static — Declare a static variable (global variable with a fixed memory location)
  • mut — Mark a binding as mutable
  • ref — Bind by reference

Type System

  • type — Create a type alias
  • struct — Define a structure/record type
  • enum — Define an enumeration type
  • trait — Define an interface type
  • impl — Implement methods or traits
  • dyn — Dynamic dispatch to a trait object
  • Self — Type alias for the implementing type within a trait or impl
  • self — Method receiver or current module
  • super — Parent module
  • where — Add constraints to generic types

Control Flow

  • if — Conditional branching
  • else — Alternative branch in conditional
  • match — Pattern matching
  • loop — Infinite loop
  • while — Conditional loop
  • for — Iterator-based loop
  • in — Part of for loop syntax and pattern matching
  • break — Exit a loop early
  • continue — Skip to the next loop iteration
  • return — Return from a function

Functions and Closures

  • fn — Define a function
  • move — Force closure to take ownership of captured variables
  • async — Define an asynchronous function or block
  • await — Suspend execution until an async result is ready

Memory Management

  • unsafe — Denote unsafe code block
  • extern — Link to external functions or crates
  • raw — Raw pointer operations (used with references)

Modules and Visibility

  • mod — Define a module
  • pub — Make an item public
  • use — Import items from other modules
  • crate — Reference the current crate or external crate
  • as — Rename or alias in imports

Macros

  • macro_rules! — Define a declarative macro

Type Operations

  • as — Type casting
  • _ — Wildcard pattern or type placeholder

Reserved for Future Use (No Functionality Yet)

  • abstract
  • become
  • box
  • do
  • final
  • macro
  • override
  • priv
  • try
  • typeof
  • unsized
  • virtual
  • yield