Versus
    32-bit vs 64-bit
    Annotations vs Decorators
    BigQuery vs Bigtable
    Block Storage vs File Storage vs Object Storage
    C vs C++
    Canvas vs SVG
    Constructor vs Init() vs Factory
    Containers vs Virtual Machines (VMs)
    DOM vs Virtual DOM vs Shadow DOM
    DQL vs DDL vs DCL vs DML
    Dagger vs Guice
    Data Mining vs Machine Learning vs Artificial Intelligence vs Data Science
    Flux vs Redux
    GCP API Gateway vs Cloud Endpoint
    GCP Cloud Run vs Cloud Functions vs App Engine
    GCP DataFlow vs Dataproc
    Google Analytics 4 vs Universal Analytics
    Google Internal vs Open Source
    HEIC vs HEIF vs HEVC vs JPEG
    Java vs C++
    Jetty vs Netty
    Kotlin vs Java
    LLVM vs JVM
    Linux vs BSD
    Microcontroller vs Microprocessor vs Computer
    Node.js vs Erlang
    POSIX vs SUS vs LSB
    Pass-by-value vs Pass-by-reference
    Proto2 vs Proto3
    PubSub vs Message Queue
    REST vs SOAP
    React vs Flutter vs Angular
    Rust vs C++
    SLI vs SLO vs SLA
    SRAM vs DRAM
    SSD vs HDD
    Software Engineer vs Site Reliability Engineer
    Spanner vs Bigtable
    Stack based VM vs Register based VM
    Stateless vs Stateful
    Static Site Generation vs Server-side Rendering vs Client-side Rendering
    Strong Consistency vs Eventual Consistency
    Subroutines vs Coroutines vs Generators
    Symlinks vs Hard Links
    Tensorflow vs PyTorch
    Terminal vs Shell
    Vi vs Vim vs gVim vs Neovim
    WAL vs rollback journal
    gtag vs Tag Manager
    stubs vs mocks vs fakes

Subroutines vs Coroutines vs Generators

Updated: 2022-02-21

Coroutines vs Subroutines

Subroutines:

  • invoked once and executes until it completed.
  • can be translated to a coroutine which does not call yield.

Coroutines:

  • a more generalized form of subroutines.
  • can be entered, exited, and resumed at many different points.
  • can pause execution and yield control back to the caller or another coroutine. The caller can then resume the coroutine when appropriate. (i.e. it may suspend its execution in one thread and resume in another one. A coroutine is not bound to any particular thread.)
  • used for cooperative multitasking and are often compared to fibers, lightweight threads and green threads

Coroutines vs Generators

Generators: a.k.a. "semicoroutines": a more limited form of coroutine that may only yield to its caller. Primarily used to simplify the writing of iterators.

Both can yield multiple times, suspending their execution and allowing re-entry at multiple entry points.

Key difference:

  • Generators: can only yield to its caller. Cannot specify a coroutine to jump to in the yield statement.
  • Coroutines: can control where execution continues immediately after they yield.

Coroutines vs Threads

  • threads: scheduled by the operating systems.
  • coroutines: scheduled by the users. (A.k.a. lightweight threads or green threads.)

Coroutines in Languages

  • C++: coroutines introduced in C++20.
  • Python:
  • Kotlin: in an extension lib kotlinx.coroutines. (NO keywords and NOT in the standard library)
    • launch, delay, suspend fun
  • Java: Project Loom.

Coroutines vs goroutines

  • goroutines imply parallelism; coroutines in general do not
  • goroutines communicate via channels; coroutines communicate via yield and resume operations

When to use Coroutines

  • data structure iterators.
  • event-driven code without the inversion of control.
  • cooperative multitasking.
  • concurrency frameworks such as actors, async-await and dataflow networks.
  • expressing asynchrony, and better composition of asynchronous systems.
  • capturing continuations.
  • expressing backtracking algorithms.
  • AI agents such as behavior trees.