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The Origins of Go

C-Like Language

Go is sometimes described as a “C-like language,” or as “C for the 21st century.”

From C, Go inherited its

• expression syntax,
• control-flow statements,
• basic data types,
• call-by-value parameter passing,
• pointers, and above all,
• C’s emphasis on programs that compile to efficient machine code and cooperate naturally with the abstractions of current operating systems.

Niklaus Wirth

But there are other ancestors in Go’s family tree. One major stream of influence comes from languages by Niklaus Wirth, beginning with

• Pascal
• Modula-2 inspired the package concept.
• Oberon eliminated the distinction between module interface files and module implementation files.
• Oberon-2 influenced the syntax for packages, imports, and declarations
• and Object Oberon provided the syntax for method declarations.

Communicating Sequential Processes (CSP)

Another lineage among Go’s ancestors, and one that makes Go distinctive among recent programming languages, is a sequence of little-known research languages developed at Bell Labs, all inspired by the concept of communicating sequential processes (CSP) from Tony Hoare’s seminal 1978 paper on the foundations of concurrency.

In CSP, a program is a parallel composition of processes that have no shared state; the processes communicate and synchro- nize using channels. But Hoare’s CSP was a formal language for describing the fundamental concepts of concurrency, not a programming language for writing executable programs.

Rob Pike Squeak

Rob Pike and others began to experiment with CSP implementations as actual languages. The first was called:

• Squeak
  • (“A language for communicating with mice”), which provided a language for handling mouse and keyboard events, with statically created channels.
• Newsqueak
  • which offered C-like statement and expression syntax and Pascal-like type notation.
  • It was a purely functional language with garbage collection, again aimed at managing keyboard, mouse, and window events.
  • Channels became first-class values, dynamically created and storable in variables.

Plan 9 and Alef

The Plan 9 operating system carried these ideas forward in a language called Alef. Alef tried to make Newsqueak a viable system programming language, but its omission of garbage collection made concurrency too painful.

Miscellaneous Sources

Other constructions in Go show the influence of non-ancestral genes here and there;

• for example iota is loosely from ‘APL’, and
• lexical scope with nested functions is from ‘Scheme’ (and most languages since).

Here too we find novel mutations.

• Go’s innovative ‘slices’ provide dynamic arrays with efficient random access but also permit sophisticated sharing arrangements reminiscent of linked lists.
• And the defer statement is new with Go.