D Programming Language

D is a general-purpose programming language designed by Walter Bright (the creator of the first C++ compiler) and Andrei Alexandrescu, first released in 2001. D combines the performance and control of C and C++ with the productivity and safety of modern high-level languages. With over 4,000 stars as of 2026, D aims to be a language that is both powerful enough for systems programming and expressive enough for application development. Key features include: multiple paradigms (procedural, object-oriented, functional, concurrent, and metaprogramming), strong static typing with type inference (auto keyword), garbage collection by default (with option for manual memory management via @nogc attribute), compile-time function execution (CTFE, running arbitrary D code at compile time), powerful template metaprogramming (more expressive and safer than C++ templates, with constraints, variadic templates, and template mixins), string mixins (generating and compiling D code from strings at compile time), contract programming (invariants, preconditions, and postconditions via in, out, and invariant blocks), scope guard statements (ensuring cleanup actions run on scope exit, failure, or success), Unicode strings as first-class types (string, wstring, dstring), Slices (array views with bounds checking), ranges (a unifying abstraction for iteration inspired by D's standard library Phobos), pure functions (guaranteed side-effect-free via pure keyword), immutable data (immutable and const qualifiers), shared memory model for multi-threading (synchronized blocks and shared type qualifier), modules and packages, operator overloading, and direct C ABI compatibility (calling C functions without wrappers).