Ada, Its Design, and the Language That Made Languages

Since the early 1980s, Ada already had designs that today's modern languages only caught up with much later.

• Packages strictly separate specification from body, with the compiler enforcing the boundary between interface and implementation.
• Private types completely hide representation, preventing clients from guessing or bypassing internal structure.
• Range types embed meaning directly into the type, as in type Age is range 0 .. 150, blocking semantic confusion at compile time.
• Discriminated records correspond to sum types / algebraic data types, with the compiler even checking which fields exist.
• Generic units provide parametric polymorphism as a standard feature, turning type-specific reusable code into a formal language feature.
• Tasking / concurrency was included in the language specification itself rather than a library, and was later joined by protected objects, null exclusion, and contracts.

The background wasn't software science but a procurement failure. In the 1970s, the DoD had to clean up a chaotic proliferation of more than 450 languages and dialects, which resulted in the Steelman requirements. These included strong static typing, separation of interface/implementation, concurrency, exception handling, machine independence, and verifiability.

Based on those requirements, the Green team was selected in 1979, and the language was named Ada. The article compares how C, Java, Python, JavaScript, Go, Rust, C#, Swift, and TypeScript each later rediscovered Ada's designs in their own ways, arguing that Ada was not an 'obscure government language' but a forerunner of modern language safety.