The Direct Lineage — Objective-C, Ruby, and Beyond

smalltalk1-5 traced Smalltalk's design and UI influence — MVC, the GUI. This chapter traces a genuinely separate thread: languages that borrowed Smalltalk's own actual syntax and semantics directly, not just its ideas about screens and windows.

Objective-C — Smalltalk's Syntax, Bolted Onto C

Brad Cox and Tom Love created Objective-C in the early 1980s by adding Smalltalk-style messaging directly on top of C — literally grafting Smalltalk's own message-send syntax onto C's existing structure. [receiver message] and [receiver message: argument] are direct syntactic descendants of Smalltalk's own keyword-message form.

This is a real, direct lineage, tied concretely back to smalltalk1-3's own core claim: in Objective-C, [myArray count] is genuinely, literally sending the message count to the object myArray — the same message-passing model as Smalltalk, syntactically dressed to sit inside C's own surrounding structure. Not "OOP inspired by OOP in general" — the actual message-send concept survived the trip into Objective-C intact, not just classes and inheritance.

Objective-C went on to become the primary language for NeXTSTEP and, for decades, macOS and iOS development, right up until Swift. For a genuinely long stretch, Smalltalk's own message-passing model was running on hundreds of millions of Apple devices — mostly invisibly, to developers who may never have heard the word "Smalltalk" at all.

Ruby — Smalltalk's Philosophy, With Friendlier Syntax

Yukihiro "Matz" Matsumoto, Ruby's creator, has explicitly and repeatedly cited Smalltalk as one of Ruby's own major influences — a stated, acknowledged influence, not speculation. Ruby's own "everything is an object" claim, already flagged in smalltalk1-3's own note-box, is inherited close to directly: 3.times { ... } is a real method call on the integer object 3, not special syntax, and nil itself is an object of class NilClass, not a special non-object null value the way many other languages treat null.

Worth revisiting ruby1-6's own material directly: Ruby's own open classes — the ability to reopen and add methods to an existing class, even a built-in one like Integer or String, at any time — are a genuinely direct descendant of the same live-editability philosophy covered in smalltalk1-4's own image and class-browser material. The idea that a class definition isn't a sealed, fixed artifact, but something you can keep live-editing at any point, is inherited close to intact.

Beyond Objective-C and Ruby — A Wider, Fainter Trail

Briefly, and without overclaiming: many other languages absorbed some Smalltalk influence more indirectly or partially. Python's own object model is less directly Smalltalk-influenced than Ruby's, but still object-uniform in spirit for many built-in types. JavaScript's own prototype-based object model is worth flagging as a genuinely separate lineage — despite a superficial "everything is dynamic and objecty" resemblance, it did not descend from Smalltalk directly, and lumping every dynamically-typed, object-heavy language together as "basically Smalltalk" would be inaccurate.

Self and Squeak are worth naming here too, as more direct — if less mainstream — descendants; smalltalk1-8 covers Squeak specifically in full as this course's own closing chapter.

How Much of "Modern OOP" Genuinely Traces Back Here

Reflection Questions