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The Origins of Go

The figure below shows the most important influences of earlier programming languages on the design of Go.

C

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: Pascal, Modula-2, Oberon, Oberon-2, Project Oberson

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.

Tony Hoare: 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 synchronize 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, Newsqueak

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.
• This was followed by 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, dynami- cally created and storable in variables.

Plan 9: 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 Others

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.