Descriptions:
The Pragmatic Engineer host Gergely Orosz interviews Anders Hejlsberg—the engineer behind Turbo Pascal, Delphi, C#, and TypeScript—in a wide-ranging conversation tracing four decades of programming language design. Hejlsberg recounts how each language emerged from distinct pressures: Turbo Pascal’s speed advantage in the early PC era (the name deliberately evoking Audi’s turbocharged quattros), C#’s birth from the wreckage of the Sun-Microsoft Java lawsuit, and TypeScript’s core insight that an erasable type system is valuable primarily because it enables better IDE tooling—not type safety as an end in itself.
The interview goes deep on language mechanics. Hejlsberg provides one of the clearest available explanations of how async/await actually works at the compiler level: the compiler transforms sequential-looking code into a state machine, moves all state that survives across await points to heap-allocated objects, and generates a switch statement to handle re-entry. He then contrasts this with OS threads and Go-style green thread goroutines, walking through the trade-offs around preemptiveness, function coloring (where async functions and regular functions cannot freely call each other), and lightweight concurrency design.
The final portion of the conversation touches on AI and programming languages—specifically whether existing languages need modification for agent use cases or whether purpose-built languages will emerge. For developers building compilers, language tooling, or AI coding assistants, this episode is a rare opportunity to hear the design rationale behind three of the most widely deployed programming languages in history from the person who built them.
📺 Source: The Pragmatic Engineer · Published May 13, 2026
🏷️ Format: Interview
