C++ and D

This page reconstructs the old “C++ vs D” note. It is about new application and systems-adjacent code you control.

Literate programming still applies: C++ codebases especially accumulate “how” without “why.”

The problem with C++ as a default

C++ is several languages in a trench coat: C with classes, template metaprogramming, a moving standard, and a culture of undefined behavior with a standards-committee changelog.

For application code — GUI hosts, tools, services that are not a browser — that budget is usually the wrong purchase:

  • Complexity is the product. Move semantics, overload resolution, header hygiene, ABI, and three ways to initialize a thing are not a learning ramp. They are a career.

  • Safety is optional. Smart pointers and guidelines help. The language still lets you alias, dangle, and race by default.

  • Build and package story is fragmented. There is no Cargo. There are a dozen CMake dialects.

A loud version of the same thesis: this C++ rant on YouTube. Use it as color, not as a citation.

What D is for here

D is the suggestion for application programming and for scripting-shaped tools that still talk to the OS:

  • Syntax that stays readable (the “Python-shaped” pitch) without shipping a massive interpreter.

  • Modules, slices, and a standard library aimed at getting work done.

  • GC when you want to think about the problem; @nogc / -betterC when you need to think about the heap. See D and Rust for the honest cost of that split.

  • C interop when you must call into an existing world.

That is the cull: **D instead of C** for owned application code, not “never call a C library.”

What this is not

  • Not a claim that game engines, Unreal, or Qt shops should rewrite next quarter.

  • Not a claim that D’s GUI ecosystem matches those incumbents. Pair D (or Rust) in the host with a webview UI when that is the product; see UI-heavy web applications.

  • Not a claim that Rust is the wrong application language. Rust is the no-GC / ecosystem pole. D is the default when you want the high-level surface.

See also