Go (programming language)

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Go
Go Logo Aqua.svg
Paradigm Multi-paradigm: procedural, object-oriented,[1] concurrent
Designed by Robert Griesemer
Rob Pike
Ken Thompson
Developer Google
First appeared 10 November 2009; 8 years ago (2009-11-10)
Stable release
1.11 / 24 August 2018; 33 days ago (2018-08-24)[2]
Typing discipline Strong, static, inferred, structural[3][4]
Implementation language Go, assembly language (gc); C++ (gccgo)
OS DragonFly BSD, FreeBSD, Linux, macOS, NetBSD, OpenBSD,[5] Plan 9,[6] Solaris, Windows
License BSD-style[7] + patent grant[8]
Filename extensions .go
Website golang.org , github.com/golang/go
Major implementations
gc, gccgo
Influenced by
Alef, APL,[9] BCPL,[9] C, CSP, Limbo, Modula, Newsqueak, Oberon, occam, Pascal,[10] Smalltalk[11]
Influenced
Crystal

Go (often referred to as Golang) is a programming language created in 2009 by Google[12] employees Robert Griesemer, Rob Pike, and Ken Thompson.[10] Go is a statically typed, compiled language in the tradition of C, with memory safety, garbage collection, structural typing,[3] and CSP-style concurrency.[13] The compiler, tools, and source code are all free and open source.[14]

History[edit]

The language was announced in November 2009.[15] Version 1.0 was released in March 2012.[16][17] It is used in some of Google's production systems, as well as by many other companies and open source projects.[18]

Go originated as an experiment by Griesemer, Pike, and Thompson to design a programming language that would resolve common criticisms of other languages while maintaining their positive characteristics. The developers envisioned the new language as:[19]

The designers cited their shared dislike of C++ as a primary motivation for designing a new language.[21][22][23]

In April 2018, the original logo (Gopher mascot) was replaced with a stylized GO slanting right with trailing streamlines. However, the mascot remained the same.

In August 2018, the Go principal contributors published two ″draft designs″ for new language features, Generics and Error Handling, and asked Go users to submit feedback on them.[24][25] Lack of support for generic programming and the verbosity of error handling in Go 1.x had drawn considerable criticism.

Current Gopher mascot and old logo.

Version history[edit]

There exist a Go 1 compatibility guarantee[26] for the language specification and major parts of the standard library. All version up to the current Go 1.10 release[27] were able to follow this guarantee.

Each major Go release is supported until there are two newer major releases.[28]

Major version Initial release date Language changes[29] Other changes
1 - 1.0.3 2012/03/28 Initial release
1.1 - 1.1.2 2013/05/13
  • In Go 1.1, an integer division by constant zero is not a legal program, so it is a compile-time error.
  • The definition of string and rune literals has been refined to exclude surrogate halves from the set of valid Unicode code points.
  • Method values
  • Loosened return requirements rules. If the compiler can proof that a function always returns before reaching the end of a function, a final terminating statement can be omitted.
  • The language allows the implementation to choose whether the int type and uint types are 32 or 64 bits.
  • On 64-bit architectures, the maximum heap size has been enlarged substantially, from a few gigabytes to several tens of gigabytes.
  • Addition of a race detector to the standard tool set.
1.2 - 1.2.2 2013/12/01
  • The language now specifies that, for safety reasons, certain uses of nil pointers are guaranteed to trigger a run-time panic.
  • Go 1.2 adds the ability to specify the capacity as well as the length when using a slicing operation on an existing array or slice. A slicing operation creates a new slice by describing a contiguous section of an already-created array or slice.
  • The runtime scheduler can now invoked on (non-inlined) function calls.
  • Go 1.2 introduces a configurable limit (default 10,000) to the total number of threads a single program may have.
  • In Go 1.2, the minimum size of the stack when a goroutine is created has been lifted from 4KB to 8KB.
1.3 - 1.3.3 2014/06/18 There are no language changes in this release.
  • The Go 1.3 memory model adds a new rule concerning sending and receiving on buffered channels, to make explicit that a buffered channel can be used as a simple semaphore, using a send into the channel to acquire and a receive from the channel to release.
  • Go 1.3 has changed the implementation of goroutine stacks away from the old, "segmented" model to a contiguous model.
  • For a while now, the garbage collector has been precise when examining values in the heap; the Go 1.3 release adds equivalent precision to values on the stack.
  • Iterations over small maps no longer happen in a consistent order. This is due to developers abusing implementation behaviour.
1.4 - 1.4.3 2014/12/10
  • Range-expression without assignment
  • Automatic double-dereference on method calls is now disallowed in gc and gccgo. This is a backwards incompatible change but inline within the language specification.
  • In 1.4, much of the runtime code has been translated to Go so that the garbage collector can scan the stacks of programs in the runtime and get accurate information about what variables are active.
  • The language accepted by the assemblers cmd/5a, cmd/6a and cmd/8a has had several changes, mostly to make it easier to deliver type information to the runtime.
  • Addition of internal packages.
  • New subcommand go generate.
1.5 - 1.5.4 2015/08/19
  • Due to an oversight, the rule that allowed the element type to be elided from slice literals was not applied to map keys. This has been corrected in Go 1.5.
  • The compiler and runtime are now implemented in Go and assembler, without C. Now that the Go compiler and runtime are implemented in Go, a Go compiler must be available to compile the distribution from source. The compiler is now self-hosted.
  • The garbage collector has been re-engineered for 1.5. The "stop the world" phase of the collector will almost always be under 10 milliseconds and usually much less.
  • In Go 1.5, the order in which goroutines are scheduled has been changed.
1.6 - 1.6.4 2016/02/17 There are no language changes in this release.
  • A major change was made to cgo defining the rules for sharing Go pointers with C code, to ensure that such C code can coexist with Go's garbage collector.
  • The Go parser is now hand-written instead of generated.
  • The go vet command now diagnoses passing function or method values as arguments to Printf, such as when passing f where f() was intended.
1.7 - 1.7.6 2016/08/15
  • Clarification on terminating statements in the language specification. This does not change existing behaviour.
  • For 64-bit x86 systems, the following instructions have been added: PCMPESTRI, RORXL, RORXQ, VINSERTI128, VPADDD, VPADDQ, VPALIGNR, VPBLENDD, VPERM2F128, VPERM2I128, VPOR, VPSHUFB, VPSHUFD, VPSLLD, VPSLLDQ, VPSLLQ, VPSRLD, VPSRLDQ, and VPSRLQ.
  • This release includes a new code generation back end for 64-bit x86 systems, based on SSA.
  • Packages using cgo may now include Fortran source files (in addition to C, C++, Objective C, and SWIG), although the Go bindings must still use C language APIs.
  • The new subcommand “go tool dist list” prints all supported operating system/architecture pairs.
1.8 - 1.8.7 2017/02/16
  • When explicitly converting a value from one struct type to another, as of Go 1.8 the tags are ignored. Thus two structs that differ only in their tags may be converted from one to the other.
  • For 64-bit x86 systems, the following instructions have been added: VBROADCASTSD, BROADCASTSS, MOVDDUP, MOVSHDUP, MOVSLDUP, VMOVDDUP, VMOVSHDUP, and VMOVSLDUP.
  • Garbage collection pauses should be significantly shorter than they were in Go 1.7, usually under 100 microseconds and often as low as 10 microseconds. See the document on eliminating stop-the-world stack re-scanning for details.
  • The overhead of deferred function calls has been reduced by about half.
  • The overhead of calls from Go into C has been reduced by about half.
1.9 - 1.9.7 2017/08/24
  • Go now supports type aliases.
  • Force the intermediate rounding in floating-point arithmetic.
  • The Go compiler now supports compiling a package's functions in parallel, taking advantage of multiple cores.
1.10 - 1.10.3 2018/02/16
  • A corner case involving shifts of untyped constants has been clarified.
  • The grammar for method expressions has been updated to relax the syntax to allow any type expression as a receiver.
  • For the X86 64-bit port, the assembler now supports 359 new instructions, including the full AVX, AVX2, BMI, BMI2, F16C, FMA3, SSE2, SSE3, SSSE3, SSE4.1, and SSE4.2 extension sets. The assembler also no longer implements MOVL $0, AX as an XORL instruction, to avoid clearing the condition flags unexpectedly.
1.11 2018/08/24 There are no changes to the language specification.
  • Go 1.11 adds an experimental port to WebAssembly.
  • Go 1.11 adds preliminary support for a new concept called “modules,” an alternative to GOPATH with integrated support for versioning and package distribution.
  • The assembler for amd64 now accepts AVX512 instructions.
  • Go 1.11 drops support of Windows XP and Windows Vista.[30]
Major version Release date Significant changes

Implementations[edit]

Two major implementations exist:

A third Go compiler, known as GopherJS[35], also exists. GopherJS compiles Go code into JavaScript code, and enables Go to be used for frontend development.

New logo.

Language design[edit]

Go is recognizably in the tradition of C, but makes many changes to improve brevity, simplicity, and safety. The language consists of:

Syntax[edit]

Go's syntax includes changes from C aimed at keeping code concise and readable. A combined declaration/initialization operator was introduced that allows the programmer to write i := 3 or s := "Hello, world!", without specifying the types of variables. This contrasts with C's int i = 3; and const char *s = "Hello, world!";. Semicolons still terminate statements[a], but are implicit when the end of a line occurs.[b] Functions may return multiple values, and returning a result, err pair is the conventional way a function indicates an error to its caller in Go.[c] Go adds literal syntaxes for initializing struct parameters by name, and for initializing maps and slices. As an alternative to C's three-statement for loop, Go's range expressions allow concise iteration over arrays, slices, strings, maps, and channels.[citation needed]

Types[edit]

Go has a number of built-in types, including numeric ones (byte, int64, float32, etc.), booleans, and character strings (string). Strings are immutable; built-in operators, and keywords (rather than functions) provide concatenation, comparison, and UTF-8 encoding/decoding.[43] Record types can be defined with the struct keyword.[citation needed]

For each type T and each non-negative integer constant n, there is an array type denoted [n]T; arrays of differing lengths are thus of different types. Dynamic arrays are available as "slices", denoted []T for some type T. These have a length and a capacity specifying when new memory needs to be allocated to expand the array. Several slices may share their underlying memory.[44][45][46]

Pointers are available for all types, and the pointer-to-T type is denoted *T. Address-taking and indirection use the & and * operators as in C, or happen implicitly through the method call or attribute access syntax.[47] There is no pointer arithmetic[d], except via the special unsafe.Pointer type in the standard library.[48]

For a pair of types K, V, the type map[K]V is the type of hash tables mapping type-K keys to type-V values. Hash tables are built into the language, with special syntax and built-in functions. chan T is a channel that allows sending values of type T between concurrent Go processes.[citation needed]

Aside from its support for interfaces, Go's type system is nominal: the type keyword can be used to define a new named type, which is distinct from other named types that have the same layout (in the case of a struct, the same members in the same order). Some conversions between types (e.g., between the various integer types) are pre-defined and adding a new type may define additional conversions, but conversions between named types must always be invoked explicitly.[49] For example, the type keyword can be used to define a type for IPv4 addresses, based on 32-bit unsigned integers.[citation needed]

type ipv4addr uint32

With this type definition, ipv4addr(x) interprets the uint32 value x as an IP address. Simply assigning x to a variable of type ipv4addr is a type error.[citation needed]

Constant expressions may be either typed or "untyped"; they are given a type when assigned to a typed variable if the value they represent passes a compile-time check.[50]

Function types are indicated by the func keyword; they take zero or more parameters and return zero or more values, all of which are typed. The parameter and return values determine a function type; thus, func(string, int32) (int, error) is the type of functions that take a string and a 32-bit signed integer, and return a signed integer (of default width) and a value of the built-in interface type error.[citation needed]

Any named type has a method set associated with it. The IP address example above can be extended with a method for checking whether its value is a known standard.

// ZeroBroadcast reports whether addr is 255.255.255.255.
func (addr ipv4addr) ZeroBroadcast() bool {
    return addr == 0xFFFFFFFF
}

Due to nominal typing, this method definition adds a method to ipv4addr, but not on uint32. While methods have special definition and call syntax, there is no distinct method type.[51]

Interface system[edit]

Go provides two features that replace class inheritance.[citation needed]

The first is embedding, which can be viewed as an automated form of composition[52] or delegation.[53]:255

The second are its interfaces, which provides runtime polymorphism.[54]:266 Interfaces are a class of types and provide a limited form of structural typing in the otherwise nominal type system of Go. An object which is of an interface type is also of another type, much like C++ objects being simultaneously of a base and derived class. Go interfaces were designed after protocols from the Smalltalk programming language.[55] Multiple sources use the term duck typing when describing Go interfaces.[56][57] Although the term duck typing is not precisely defined and therefore not wrong, it usually implies that type conformance is not statically checked. Since conformance to a Go interface is checked statically by the Go compiler (except when performing a type assertion), the Go authors prefer the term structural typing.[58]

The definition of an interface type lists required methods by name and type. Any object of type T for which functions exist matching all the required methods of interface type I is an object of type I as well. The definition of type T need not (and cannot) identify type I. For example, if Shape, Square and Circle are defined as:

import "math"

type Shape interface {
    Area() float64
}

type Square struct { // Note: no "implements" declaration
    side float64
}

func (sq Square) Area() float64 { return sq.side * sq.side }

type Circle struct { // No "implements" declaration here either
    radius float64
}

func (c Circle) Area() float64 { return math.Pi * math.Pow(c.radius, 2) }

Both a Square and a Circle are implicitly a Shape and can be assigned to a Shape-typed variable.[54]:263–268 In formal language, Go's interface system provides structural rather than nominal typing. Interfaces can embed other interfaces with the effect of creating a combined interface that is satisfied by exactly the types that implement the embedded interface and any methods that the newly defined interface adds.[54]:270

The Go standard library uses interfaces to provide genericity in several places, including the input/output system that is based on the concepts of Reader and Writer.[54]:282–283

Besides calling methods via interfaces, Go allows converting interface values to other types with a run-time type check. The language constructs to do so are the type assertion,[59] which checks against a single potential type, and the type switch,[60] which checks against multiple types.[citation needed]

The empty interface interface{} is an important base case because it can refer to an item of any concrete type. It is similar to the Object class in Java or C# and is satisfied by any type, including built-in types like int.[54]:284 Code using the empty interface cannot simply call methods (or built-in operators) on the referred-to object, but it can store the interface{} value, try to convert it to a more useful type via a type assertion or type switch, or inspect it with Go's reflect package.[61] Because interface{} can refer to any value, it is a limited way to escape the restrictions of static typing, like void* in C but with additional run-time type checks.[citation needed]

Interface values are implemented using pointer to data and a second pointer to run-time type information.[62] Like some other types implemented using pointers in Go, interface values are nil if uninitialized.[63]

Package system[edit]

In Go's package system, each package has a path (e.g., "compress/bzip2" or "golang.org/x/net/html") and a name (e.g., bzip2 or html). References to other packages' definitions must always be prefixed with the other package's name, and only the capitalized names from other packages are accessible: io.Reader is public but bzip2.reader is not.[64] The go get command can retrieve packages stored in a remote repository such as GitHub,[65] and developers are encouraged to develop packages inside a base path corresponding to a source repository (such as github.com/user_name/package_name) to reduce the likelihood of name collision with future additions to the standard library or other external libraries.[66]

Proposals exist to introduce a proper package management solution for Go similar to Rust's cargo system or Node's npm system.[67]

Concurrency: goroutines and channels[edit]

The Go language has built-in facilities, as well as library support, for writing concurrent programs. Concurrency refers not only to CPU parallelism, but also to asynchrony: letting slow operations like a database or network-read run while the program does other work, as is common in event-based servers.[68]

The primary concurrency construct is the goroutine, a type of light-weight process. A function call prefixed with the go keyword starts a function in a new goroutine. The language specification does not specify how goroutines should be implemented, but current implementations multiplex a Go process's goroutines onto a smaller set of operating system threads, similar to the scheduling performed in Erlang.[69]:10

While a standard library package featuring most of the classical concurrency control structures (mutex locks, etc.) is available,[69]:151–152 idiomatic concurrent programs instead prefer channels, which provide send messages between goroutines.[70] Optional buffers store messages in FIFO order[53]:43 and allow sending goroutines to proceed before their messages are received.[citation needed]

Channels are typed, so that a channel of type chan T can only be used to transfer messages of type T. Special syntax is used to operate on them; <-ch is an expression that causes the executing goroutine to block until a value comes in over the channel ch, while ch <- x sends the value x (possibly blocking until another goroutine receives the value). The built-in switch-like select statement can be used to implement non-blocking communication on multiple channels; see below for an example. Go has a memory model describing how goroutines must use channels or other operations to safely share data.[71]

The existence of channels sets Go apart from actor model-style concurrent languages like Erlang, where messages are addressed directly to actors (corresponding to goroutines). The actor style can be simulated in Go by maintaining a one-to-one correspondence between goroutines and channels, but the language allows multiple goroutines to share a channel or a single goroutine to send and receive on multiple channels.[69]:147

From these tools one can build concurrent constructs like worker pools, pipelines (in which, say, a file is decompressed and parsed as it downloads), background calls with timeout, "fan-out" parallel calls to a set of services, and others.[72] Channels have also found uses further from the usual notion of interprocess communication, like serving as a concurrency-safe list of recycled buffers,[73] implementing coroutines (which helped inspire the name goroutine),[74] and implementing iterators.[75]

Concurrency-related structural conventions of Go (channels and alternative channel inputs) are derived from Tony Hoare's communicating sequential processes model. Unlike previous concurrent programming languages such as Occam or Limbo (a language on which Go co-designer Rob Pike worked),[76] Go does not provide any built-in notion of safe or verifiable concurrency.[77] While the communicating-processes model is favored in Go, it is not the only one: all goroutines in a program share a single address space. This means that mutable objects and pointers can be shared between goroutines; see § Lack of race condition safety, below.[citation needed]

Suitability for parallel programming[edit]

Although Go's concurrency features are not aimed primarily at parallel processing,[68] they can be used to program shared memory multi-processor machines. Various studies have been done into the effectiveness of this approach.[78] One of these studies compared the size (in lines of code) and speed of programs written by a seasoned programmer not familiar with the language and corrections to these programs by a Go expert (from Google's development team), doing the same for Chapel, Cilk and Intel TBB. The study found that the non-expert tended to write divide-and-conquer algorithms with one go statement per recursion, while the expert wrote distribute-work-synchronize programs using one goroutine per processor. The expert's programs were usually faster, but also longer.[79]

Lack of race condition safety[edit]

There are no restrictions on how goroutines access shared data, making race conditions possible. Specifically, unless a program explicitly synchronizes via channels or other means, writes from one goroutine might be partly, entirely, or not at all visible to another, often with no guarantees about ordering of writes.[77] Furthermore, Go's internal data structures like interface values, slice headers, hash tables, and string headers are not immune to race conditions, so type and memory safety can be violated in multithreaded programs that modify shared instances of those types without synchronization.[80][81] Instead of language support, safe concurrent programming thus relies on conventions; for example, Chisnall recommends an idiom called "aliases xor mutable", meaning that passing a mutable value (or pointer) over a channel signals a transfer of ownership over the value to its receiver.[69]:155

Binaries[edit]

The linker in the gc toolchain creates statically-linked binaries by default therefore all Go binaries include the Go runtime. [82][83]

Omissions[edit]

Go deliberately omits certain features common in other languages, including (implementation) inheritance, generic programming, assertions,[e] pointer arithmetic,[d] implicit type conversions, untagged unions,[f] and tagged unions.[g] The designers added only those facilities that all three agreed on.[86]

Of the omitted language features, the designers explicitly argue against assertions and pointer arithmetic, while defending the choice to omit type inheritance as giving a more useful language, encouraging instead the use of interfaces to achieve dynamic dispatch[h] and composition to reuse code. Composition and delegation are in fact largely automated by struct embedding; according to researchers Schmager et al., this feature "has many of the drawbacks of inheritance: it affects the public interface of objects, it is not fine-grained (i.e, no method-level control over embedding), methods of embedded objects cannot be hidden, and it is static", making it "not obvious" whether programmers will overuse it to the extent that programmers in other languages are reputed to overuse inheritance.[52]

The designers express an openness to generic programming and note that built-in functions are in fact type-generic, but these are treated as special cases; Pike calls this a weakness that may at some point be changed.[44] The Google team built at least one compiler for an experimental Go dialect with generics, but did not release it.[87] They are also open to standardizing ways to apply code generation.[88]

Initially omitted, the exception-like panic/recover mechanism was eventually added, which the Go authors advise using for unrecoverable errors such as those that should halt an entire program or server request, or as a shortcut to propagate errors up the stack within a package (but not across package boundaries; there, error returns are the standard API).[89][90][91][92]

Criticism[edit]

Go critics assert that:

The designers argue that these trade-offs are important to Go's success.[100] They explain particular decisions at length.[101]

GC has been improved to sub-millisecond GC pause times in later versions.[102][103][104] However, the developers acknowledge that this GC algorithm is not hard real-time.[citation needed]

Conventions and code style[edit]

The Go authors put substantial effort into molding the style and design of Go programs:

  • Indentation, spacing, and other surface-level details of code are automatically standardized by the gofmt tool. golint does additional style checks automatically.
  • Tools and libraries distributed with Go suggest standard approaches to things like API documentation (godoc),[105] testing (go test), building (go build), package management (go get), and so on.
  • Go enforces rules that are recommendations in other languages, for example banning cyclic dependencies, unused variables or imports, and implicit type conversions.
  • The omission of certain features (for example, functional-programming shortcuts like map and Java-style try/finally blocks) tends to encourage a particular explicit, concrete, and imperative programming style.
  • On day one the Go team published a collection of Go idioms,[105] and later also collected code review comments,[106] talks,[107] and official blog posts[108] to teach Go style and coding philosophy.

Tools[edit]

Go includes the same sort of debugging, testing, and code-vetting tools as many language distributions. The Go distribution includes, among other tools,

  • go build, which builds Go binaries using only information in the source files themselves, no separate makefiles
  • go test, for unit testing and microbenchmarks
  • go fmt, for formatting code
  • go get, for retrieving and installing remote packages
  • go vet, a static analyzer looking for potential errors in code
  • go run, a shortcut for building and executing code
  • godoc, for displaying documentation or serving it via HTTP
  • gorename, for renaming variables, functions, and so on in a type-safe way
  • go generate, a standard way to invoke code generators

It also includes profiling and debugging support, runtime instrumentation (to, for example, track garbage collection pauses), and a race condition tester.

An ecosystem of third-party tools adds to the standard distribution, such as gocode, which enables code autocompletion in many text editors, goimports (by a Go team member), which automatically adds/removes package imports as needed, and errcheck, which detects code that might unintentionally ignore errors. Plugins exist for adding language support to several text editors. Several IDEs are available. For instance, LiteIDE, which is branded as "a simple, open source, cross-platform Go IDE",[109] and GoLand, which claims to be "capable and ergonomic."[110]

Examples[edit]

Hello world[edit]

Here is a Hello world program in Go:

package main

import "fmt"

func main() {
    fmt.Println("Hello, World")
}

Concurrency example[edit]

The following simple program demonstrates Go's concurrency features to implement an asynchronous program. It launches two "goroutines" (lightweight threads): one waits for the user to type some text, while the other implements a timeout. The select statement waits for either of these goroutines to send a message to the main routine, and acts on the first message to arrive (example adapted from David Chisnall book).[69]:152

package main

import (
    "fmt"
    "time"
)

func readword(ch chan string) {
    fmt.Println("Type a word, then hit Enter.")
    var word string
    fmt.Scanf("%s", &word)
    ch <- word
}

func timeout(t chan bool) {
    time.Sleep(5 * time.Second)
    t <- false
}

func main() {
    t := make(chan bool)
    go timeout(t)

    ch := make(chan string)
    go readword(ch)

    select {
    case word := <-ch:
        fmt.Println("Received", word)
    case <-t:
        fmt.Println("Timeout.")
    }
}

Projects[edit]

Some notable open-source applications in Go include:[111]

Other notable companies and sites using Go (generally together with other languages, not exclusively) include:[115][self-published source?][116]

Reception[edit]

The interface system, and the deliberate omission of inheritance, were praised by Michele Simionato, who likened these characteristics to those of Standard ML, calling it "a shame that no popular language has followed [this] particular route".[138]

Dave Astels at Engine Yard wrote:[139]

Go is extremely easy to dive into. There are a minimal number of fundamental language concepts and the syntax is clean and designed to be clear and unambiguous. Go is still experimental and still a little rough around the edges.

Go was named Programming Language of the Year by the TIOBE Programming Community Index in its first year, 2009, for having a larger 12-month increase in popularity (in only 2 months, after its introduction in November) than any other language that year, and reached 13th place by January 2010,[140] surpassing established languages like Pascal. By June 2015, its ranking had dropped to below 50th in the index, placing it lower than COBOL and Fortran.[141] But as of January 2017, its ranking had surged to 13th, indicating significant growth in popularity and adoption. Go was awarded TIOBE programming language of the year 2016.

Bruce Eckel has stated:[142]

The complexity of C++ (even more complexity has been added in the new C++), and the resulting impact on productivity, is no longer justified. All the hoops that the C++ programmer had to jump through in order to use a C-compatible language make no sense anymore -- they're just a waste of time and effort. Go makes much more sense for the class of problems that C++ was originally intended to solve.

A 2011 evaluation of the language and its gc implementation in comparison to C++ (GCC), Java and Scala by a Google engineer found:

Go offers interesting language features, which also allow for a concise and standardized notation. The compilers for this language are still immature, which reflects in both performance and binary sizes.

— R. Hundt[143]

The evaluation got a rebuttal from the Go development team. Ian Lance Taylor, who had improved the Go code for Hundt's paper, had not been aware of the intention to publish his code, and says that his version was "never intended to be an example of idiomatic or efficient Go"; Russ Cox then did optimize the Go code, as well as the C++ code, and got the Go code to run slightly faster than C++ and more than an order of magnitude faster than the code in the paper.[144]

Naming dispute[edit]

On 10 November 2009, the day of the general release of the language, Francis McCabe, developer of the Go! programming language (note the exclamation point), requested a name change of Google's language to prevent confusion with his language, which he had spent 10 years developing.[145] McCabe raised concerns that "the 'big guy' will end up steam-rollering over" him, and this concern resonated with the more than 120 developers who commented on Google's official issues thread saying they should change the name, with some[146] even saying the issue contradicts Google's motto of: Don't be evil.[147]

On 12 October 2010, the issue was closed by Google developer Russ Cox (@rsc) with the custom status "Unfortunate" accompanied by the following comment:

"There are many computing products and services named Go. In the 11 months since our release, there has been minimal confusion of the two languages."[147]

See also[edit]

Notes[edit]

  1. ^ but "To allow complex statements to occupy a single line, a semicolon may be omitted before a closing ) or }".[41]
  2. ^ “if the newline comes after a token that could end a statement, [the lexer will] insert a semicolon”.[42]
  3. ^ Usually, exactly one of the result and error values has a value other than the type's zero value; sometimes both do, as when a read or write can only be partially completed, and sometimes neither, as when a read returns 0 bytes. See Semipredicate problem: Multivalued return.
  4. ^ a b Language FAQ "Why is there no pointer arithmetic? Safety … never derive an illegal address that succeeds incorrectly … using array indices can be as efficient as … pointer arithmetic … simplify the implementation of the garbage collector…."[10]
  5. ^ Language FAQ "Why does Go not have assertions? …our experience has been that programmers use them as a crutch to avoid thinking about proper error handling and reporting…."[10]
  6. ^ Language FAQ "Why are there no untagged unions…? [they] would violate Go's memory safety guarantees."[10]
  7. ^ Language FAQ "Why does Go not have variant types? … We considered [them but] they overlap in confusing ways with interfaces…. [S]ome of what variant types address is already covered, … although not as elegantly."[10] (The tag of an interface type[84] is accessed with a type assertion[85]).
  8. ^ Questions "How do I get dynamic dispatch of methods?" and "Why is there no type inheritance?" in the language FAQ.[10]

References[edit]

  1. ^ "Go: code that grows with grace". Retrieved 24 June 2018. 
  2. ^ "Release History - The Go Programming Language". Retrieved 8 June 2018. 
  3. ^ a b "Why doesn't Go have "implements" declarations?". golang.org. Retrieved 1 October 2015. 
  4. ^ Pike, Rob (2014-12-22). "Rob Pike on Twitter". Retrieved 2016-03-13. Go has structural typing, not duck typing. Full interface satisfaction is checked and required. 
  5. ^ "lang/go: go-1.4 – Go programming language". OpenBSD ports. 2014-12-23. Retrieved 2015-01-19. 
  6. ^ "Go Porting Efforts". Go Language Resources. cat-v. 12 January 2010. Retrieved 18 January 2010. 
  7. ^ "Text file LICENSE". The Go Programming Language. Google. Retrieved 5 October 2012. 
  8. ^ "Additional IP Rights Grant". The Go Programming Language. Google. Retrieved 5 October 2012. 
  9. ^ a b Pike, Rob (2014-04-24). "Hello Gophers". Retrieved 2016-03-11. 
  10. ^ a b c d e f g "Language Design FAQ". golang.org. 16 January 2010. Retrieved 27 February 2010. 
  11. ^ "The Evolution of Go". Retrieved 2015-09-26. 
  12. ^ Kincaid, Jason (10 November 2009). "Google's Go: A New Programming Language That's Python Meets C++". TechCrunch. Retrieved 18 January 2010. 
  13. ^ a b Metz, Cade (5 May 2011). "Google Go boldly goes where no code has gone before". The Register. 
  14. ^ "LICENSE - The Go Programming Language". golang.org. 
  15. ^ Griesemer, Robert; Pike, Rob; Thompson, Ken; Taylor, Ian; Cox, Russ; Kim, Jini; Langley, Adam. "Hey! Ho! Let's Go!". Google Open Source. Google. Retrieved 17 May 2018. 
  16. ^ Shankland, Stephen (2012-03-30). "Google's Go language turns one, wins a spot at YouTube: The lower-level programming language has matured enough to sport the 1.0 version number. And it's being used for real work at Google". News. CNet. CBS Interactive Inc. Retrieved 2017-08-06. Google has released version 1 of its Go programming language, an ambitious attempt to improve upon giants of the lower-level programming world such as C and C++. 
  17. ^ "Release History". 
  18. ^ "Go FAQ: Is Google using Go internally?". Retrieved 2013-03-09. 
  19. ^ Pike, Rob (28 April 2010). "Another Go at Language Design". Stanford EE Computer Systems Colloquium. Stanford University.  Video available.
  20. ^ "Frequently Asked Questions (FAQ) - The Go Programming Language". golang.org. Retrieved 2016-02-26. 
  21. ^ Andrew Binstock (18 May 2011). "Dr. Dobb's: Interview with Ken Thompson". Retrieved 2014-02-07. 
  22. ^ Pike, Rob (2012). "Less is exponentially more". 
  23. ^ Robert Griesemer (2015). "The Evolution of Go". 
  24. ^ "Go 2 Draft Designs". Retrieved 12 September 2018. 
  25. ^ "The Go Blog: Go 2 Draft Designs". 28 August 2018. 
  26. ^ "Go 1 and the Future of Go Programs". 
  27. ^ "Go 1.10 Release Notes". 
  28. ^ "Release History". 
  29. ^ "Release History - The Go Programming Language". golang.org. Retrieved 2018-08-24. 
  30. ^ https://golang.org/doc/go1.11
  31. ^ "Google's In-House Programming Language Now Runs on Phones". wired.com. 19 August 2015. 
  32. ^ "Go 1.5 Release Notes". Retrieved 28 January 2016. The compiler and runtime are now implemented in Go and assembler, without C. 
  33. ^ "FAQ: Implementation". golang.org. 16 January 2010. Retrieved 2010-01-18. 
  34. ^ "Installing GCC: Configuration". Retrieved 2011-12-03. Ada, Go and Objective-C++ are not default languages 
  35. ^ https://github.com/gopherjs/gopherjs
  36. ^ Pike, Rob. "The Go Programming Language". YouTube. Retrieved 2011-07-01. 
  37. ^ Rob Pike (10 November 2009). The Go Programming Language (flv) (Tech talk). Google. Event occurs at 8:53. 
  38. ^ Download and install packages and dependencies - go - The Go Programming Language; see godoc.org for addresses and documentation of some packages
  39. ^ "GoDoc". godoc.org. 
  40. ^ Rob Pike, on The Changelog podcast
  41. ^ "Go Programming Language Specification, §Semicolons". golang.org. 
  42. ^ "Effective Go, §Semicolons". golang.org. 
  43. ^ Rob Pike, Strings, bytes, runes and characters in Go, 23 October 2013
  44. ^ a b Pike, Rob (26 September 2013). "Arrays, slices (and strings): The mechanics of 'append'". The Go Blog. Retrieved 7 March 2015. 
  45. ^ Andrew Gerrand, Go Slices: usage and internals
  46. ^ The Go Authors, Effective Go: Slices
  47. ^ The Go authors Selectors - The Go Programming Language Specification and Calls - The Go Programming Language Specification
  48. ^ "Go Programming Language Specification, §Package unsafe". golang.org. 
  49. ^ "The Go Programming Language Specification". golang.org. 
  50. ^ "The Go Programming Language Specification". golang.org. 
  51. ^ "The Go Programming Language Specification". golang.org. 
  52. ^ a b Schmager, Frank; Cameron, Nicholas; Noble, James (2010). GoHotDraw: evaluating the Go programming language with design patterns. Evaluation and Usability of Programming Languages and Tools. ACM. 
  53. ^ a b Summerfield, Mark (2012). Programming in Go: Creating Applications for the 21st Century. Addison-Wesley. 
  54. ^ a b c d e Balbaert, Ivo (2012). The Way to Go: A Thorough Introduction to the Go Programming Language. iUniverse. 
  55. ^ "The Evolution of Go". talks.golang.org. Retrieved 2016-03-13. 
  56. ^ Diggins, Christopher (2009-11-24). "Duck Typing and the Go Programming Language". Dr. Dobb's. Retrieved 2016-03-10. 
  57. ^ Ryer, Mat (2015-12-01). "Duck typing in Go". Retrieved 2016-03-10. 
  58. ^ "Frequently Asked Questions (FAQ) - The Go Programming Language". golang.org. 
  59. ^ "The Go Programming Language Specification". golang.org. 
  60. ^ "The Go Programming Language Specification". golang.org. 
  61. ^ reflect.ValueOf(i interface{}) converts an interface{} to a reflect.Value that can be further inspected
  62. ^ "Go Data Structures: Interfaces". Retrieved 15 November 2012. 
  63. ^ "The Go Programming Language Specification". golang.org. 
  64. ^ "A Tutorial for the Go Programming Language". The Go Programming Language. Google. Retrieved 10 March 2013. In Go the rule about visibility of information is simple: if a name (of a top-level type, function, method, constant or variable, or of a structure field or method) is capitalized, users of the package may see it. Otherwise, the name and hence the thing being named is visible only inside the package in which it is declared. 
  65. ^ "go - The Go Programming Language". golang.org. 
  66. ^ "How to Write Go Code". golang.org. The packages from the standard library are given short import paths such as "fmt" and "net/http". For your own packages, you must choose a base path that is unlikely to collide with future additions to the standard library or other external libraries. If you keep your code in a source repository somewhere, then you should use the root of that source repository as your base path. For instance, if you have a GitHub account at github.com/user, that should be your base path 
  67. ^ "Go Packaging Proposal Process". 
  68. ^ a b Rob Pike, Concurrency is not Parallelism
  69. ^ a b c d e Chisnall, David (2012). The Go Programming Language Phrasebook. Addison-Wesley. 
  70. ^ "Effective Go". golang.org. 
  71. ^ "The Go Memory Model". Retrieved 10 April 2017. 
  72. ^ "Go Concurrency Patterns". golang.org. 
  73. ^ John Graham-Cumming, Recycling Memory Buffers in Go
  74. ^ "tree.go". 
  75. ^ Ewen Cheslack-Postava, Iterators in Go
  76. ^ Brian W. Kernighan, A Descent Into Limbo
  77. ^ a b "The Go Memory Model". Google. Retrieved 5 January 2011. 
  78. ^ Tang, Peiyi (2010). Multi-core parallel programming in Go (PDF). Proc. First International Conference on Advanced Computing and Communications. 
  79. ^ Nanz, Sebastian; West, Scott; Soares Da Silveira, Kaue. Examining the expert gap in parallel programming (PDF). Euro-Par 2013. CiteSeerX 10.1.1.368.6137Freely accessible. 
  80. ^ Russ Cox, Off to the Races
  81. ^ Pike, Rob (25 October 2012). "Go at Google: Language Design in the Service of Software Engineering". Google, Inc.  "There is one important caveat: Go is not purely memory safe in the presence of concurrency."
  82. ^ https://golang.org/doc/faq
  83. ^ https://hackernoon.com/a-story-of-a-fat-go-binary-20edc6549b97
  84. ^ "Go Programming Language Specification, §Interface types". golang.org. 
  85. ^ "Go Programming Language Specification, §Type assertions". golang.org. 
  86. ^ "All Systems Are Go". informIT. 2010-08-17. Retrieved 2018-06-21. 
  87. ^ "E2E: Erik Meijer and Robert Griesemer – Going Go". Channel 9. Microsoft. 7 May 2012. 
  88. ^ Rob Pike, Generating code
  89. ^ Panic And Recover, Go wiki
  90. ^ "Weekly Snapshot History". golang.org. 
  91. ^ "Proposal for an exception-like mechanism". golang-nuts. 25 March 2010. Retrieved 25 March 2010. 
  92. ^ "Effective Go". golang.org. 
  93. ^ a b c d Will Yager, Why Go is not Good
  94. ^ Egon Elbre, Summary of Go Generics discussions
  95. ^ Fitzpatrick, Brad. "Go: 90% Perfect, 100% of the time". Retrieved 28 January 2016. 
  96. ^ Andrew Morgan, "What I Don’t Like About Error Handling in Go, and How to Work Around It"
  97. ^ Danny Gratzer, Leaving Go
  98. ^ a b Jared Forsyth, Rust vs. Go
  99. ^ Janos Dobronszki, Everyday Hassles in Go
  100. ^ Rob Pike, Less is exponentially more
  101. ^ The Go Authors, Frequently Asked Questions (FAQ)
  102. ^ Rhys Hiltner (2016-07-05). "Go's march to low-latency GC". Twitch.tv. It’s the story of how improvements to the Go runtime between Go 1.4 and Go 1.6 gave us a 20x improvement in garbage collection (GC) pause time, of how we’ve gotten another 10x improvement in Go 1.6’s pauses, and of how sharing our experience with the Go runtime team helped them give us an additional 10x speedup in Go 1.7 while obsoleting our manual tuning. 
  103. ^ Richard Hudson, Go 1.4+ Garbage Collection (GC) Plan and Roadmap
  104. ^ Hatfield, Brian (2016-12-01). "SUB. MILLISECOND. PAUSE. TIME. ON. AN. 18. GIG. HEAP". Retrieved 2017-10-07. 
  105. ^ a b "Effective Go". golang.org. 
  106. ^ "Code Review Comments". Retrieved 3 July 2018. 
  107. ^ "Talks". Retrieved 3 July 2018. 
  108. ^ "Errors Are Values". Retrieved 3 July 2018. 
  109. ^ "visualfc/liteide". GitHub. 
  110. ^ "GoLand: A Clever IDE to Go by JetBrains". JetBrains. 
  111. ^ avelino/awesome-go: A curated list of awesome Go frameworks, libraries and software, retrieved 2018-01-10 
  112. ^ dcrd: Decred daemon in Go (golang), Decred, 2017-12-18, retrieved 2017-12-19 
  113. ^ "ipfs/go-ipfs". GitHub. Retrieved 2018-06-01. 
  114. ^ Lightning Developers Network installation guide 
  115. ^ Erik Unger, The Case For Go
  116. ^ Andrew Gerrand, Four years of Go, The Go Blog
  117. ^ "Test driven development in Go | Cacoo". Cacoo. 2016-07-29. Retrieved 2018-06-01. 
  118. ^ "Chango". GitHub. 
  119. ^ John Graham-Cumming, Go at CloudFlare
  120. ^ John Graham-Cumming, What we've been doing with Go
  121. ^ "Go at CoreOS". 
  122. ^ "Couchbase". GitHub. 
  123. ^ Patrick Lee, Open Sourcing Our Go Libraries, 7 July 2014.
  124. ^ "dl.google.com: Powered by Go". golang.org. 
  125. ^ Matt Welsh, Rewriting a Large Production System in Go
  126. ^ David Symonds, High Performance Apps on Google App Engine
  127. ^ "Mongo DB". GitHub. 
  128. ^ "The Netflix Tech Blog: Application data caching using SSDs". 
  129. ^ "Google+ post by Don Dwoske". Google+. Retrieved 2017-01-21. 
  130. ^ "golang/go". GitHub. 
  131. ^ Steven Sacks. "Search & Advances". plug.dj tech blog. 
  132. ^ Tim Jenkins. "How to Convince Your Company to Go With Golang". SendGrid's Email Deliverability Blog. 
  133. ^ Peter Bourgon, Go at SoundCloud
  134. ^ "Go at Google I/O and Gopher SummerFest - The Go Blog". golang.org. 
  135. ^ TWSTRIKE. "CoyIM". ThoughtWorks STRIKE team. 
  136. ^ Rhys Hiltner, Go’s march to low-latency GC, 5 July 2016.
  137. ^ "How We Built Uber Engineering's Highest Query per Second Service Using Go". Uber Engineering Blog. Retrieved 2016-03-02. 
  138. ^ Simionato, Michele (15 November 2009). "Interfaces vs Inheritance (or, watch out for Go!)". artima. Retrieved 15 November 2009. 
  139. ^ Astels, Dave (9 November 2009). "Ready, Set, Go!". engineyard. Retrieved 9 November 2009. 
  140. ^ jt. "Google's Go Wins Programming Language Of The Year Award". jaxenter. Retrieved 5 December 2012. 
  141. ^ "TIOBE Programming Community Index for June 2015". TIOBE Software. June 2015. Retrieved 5 July 2015. 
  142. ^ Bruce Eckel (27 August 2011). "Calling Go from Python via JSON-RPC". Retrieved 29 August 2011. 
  143. ^ Hundt, Robert (2011). Loop recognition in C++/Java/Go/Scala (PDF). Scala Days. 
  144. ^ Metz, Cade (1 July 2011). "Google Go strikes back with C++ bake-off". The Register. 
  145. ^ Brownlee, John (13 November 2009). "Google didn't google "Go" before naming their programming language'". 
  146. ^ Claburn, Thomas (11 November 2009). "Google 'Go' Name Brings Accusations Of Evil'". InformationWeek. Retrieved 18 January 2010. 
  147. ^ a b "Issue 9 - go — I have already used the name for *MY* programming language". Google Code. Google Inc. Retrieved 12 October 2010. 

External links[edit]