What Does the '.' Mean in Go's `import` Statements?

Understanding the Significance of the '.' in Go Import Statements

In the Go programming language, the '.' (dot or period) in an import statement plays a crucial role in determining the accessibility of identifiers within the imported package. It allows developers to access exported identifiers from the imported package without specifying a qualifier.

The Go tutorial and most Go code often import packages using statements like:

import (
    "fmt"
    "os"
    "launchpad.net/lpad"
    ...
)

In this example, the imported identifiers, such as fmt.Println and os.Exit, require qualifiers (fmt and os, respectively) to be used within the current file block.

However, in some cases, the gocheck package is imported with a '.' (period) as seen in this example:

import (
    "http"
    . "launchpad.net/gocheck"
    "launchpad.net/lpad"
    "os"    
)

The significance of the '.' in this statement is to declare all the exported identifiers from the gocheck package in the current file block. This means that identifiers from gocheck can be used directly without a qualifier. For instance, instead of writing:

gocheck.Suite

You can simply use:

Suite

This abbreviated syntax is particularly beneficial when working with multiple imported packages that involve frequent use of specific identifiers. It enhances code readability and reduces the need for repeated qualifiers.

It's important to note that the '.' import style should only be used for packages whose identifiers are not likely to conflict with those in other imported packages. If there is a potential for name clashes, it is recommended to use explicit qualifiers to avoid ambiguity.

Understanding the role of the '.' in Go import statements empowers developers to better organize and structure their code. It allows for efficient access to exported identifiers, improving readability and maintainability.

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