Why Does Go Include the 'goto' Statement?

Go's "goto" Statement and Its Purpose

Contrary to the common perception of "goto" statements as a programming practice of the past, Go surprisingly includes them in its syntax. Questions have arisen regarding the rationale behind this decision, despite the widely held belief that functions and methods are superior for flow control.

Google's Motivation for Including "goto"

The presence of "goto" statements in Go's codebase suggests that they serve a specific purpose. Examining the source code of the Go standard library reveals instances where "goto" is employed judiciously.

An Example from the Math Library

In the math/gamma.go file, "goto" is used in the following manner:

for x < 0 {
    if x > -1e-09 {
      goto small
    }
    z = z / x
    x = x + 1
}
for x < 2 {
    if x < 1e-09 {
      goto small
    }
    z = z / x
    x = x + 1
}

// (Rest of the code omitted)

small:
  if x == 0 {
    return Inf(1)
  }
  return z / ((1 + Euler*x) * x)
}

In this example, the "goto small" statement allows for a concise and comprehensible exit from nested loops, without the need for an auxiliary variable for control flow. This simplifies the readability and maintainability of the code by eliminating unnecessary complexity.

Restrictions on "goto"

It is important to note that Go's "goto" statement is subject to certain limitations. It cannot be used to jump over variables coming into scope or into different code blocks. These restrictions ensure that "goto" is used responsibly and does not compromise code clarity or predictability.

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