features.md

Programming Language Features

Good

AST Library

• Go ast
  • API is really complex

Compile-Time Code Generation

• Go generate
  • Compiles from strings -- AST or hybrid would be nicer
  • Or some inline generation syntax?

Runtime Code Generation

• C libtcc
  • Compiles from strings -- AST or hybrid would be nicer
  • Or some inline generation syntax?

Reflection

• Go reflect

Struct Tags

• Go struct tags

Decorators

• Python decorators

Automatic Object-Level Concurrency Isolation

• Swift actor
  • This is broken for async

Reference Counting

• Python garbage collector
• Swift automatic reference counting

Channels

• Go channel basics
• Go channel buffering
  • The constant here has always seemed a bit sloppy
  • Usually you want 0, 1, or infinite
• Go channel range, close

Inclusive and Exclusive Range

• Swift range

Select

• Go select
• Go select default

Hidden Event Loop Singleton

• libuv
  • Efficient (epoll on Linux, kqueue on Darwin/BSD)
  • Timeouts (min heap)
  • File descriptors
  • Signals (signalfd on Linux)
  • Processes (pidfd on Linux)

Async Semaphore / Mutex

• JavaScript async mutex

Async Sleep

• Python asyncio.sleep vs time.sleep

Every Value Can Hold An Error

• C++ ErrorOr<>
• Should propagate up automatically
  • Attempt to operate on an error value returns immediately with the same error

Composable Errors

• Go errors.Join
• Go errors.As

List Comprehensions

• Python list comprehensions
• Encapsulates filter and map

Type Inference In All Directions

• Function arguments (bidirectional)
• Return types (bidirectional)

Trailing Closure Syntax

• Swift trailing closure syntax

Automatic Parallelization

• Wikipedia: Automatic parallelization

Protocols

• Swift protocols

Mid-Block Optional Unwrapping

• Swift guard optional unwrapping

if Optional Unwrapping

• Swift if let optional unwrapping

Any Type

• Go any

Automatic Named Tuple Types

• Swift tuples

Argument Name Overloading

• Swift argument name overloading

Transparent Context / Task Local Variables

• Swift task local values

Bad

Explicit async/await

• Should be automatic like Go
• Swift async/await
• JavaScript async/await

Explicit try

• Should be automatic like JavaScript
• Swift try

Explicit range

• Should be automatic like Swift
• Go range

Explicit context

• Should be automatic like Swift
• Go context

Getters & Setters

• Function calls should look like function calls
• Swift computed properties