October 2015
Beginner to intermediate
400 pages
14h 44m
English
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10.5 Blank Imports
It is an error to import a package into a file but not refer to the
name it defines within that file.
However, on occasion we must import a package merely for the side
effects of doing so: evaluation of the initializer expressions of its
package-level variables and execution of its init functions
(§2.6.2).
To suppress the “unused import” error we would otherwise encounter, we
must use a renaming import in which the alternative name is _, the
blank identifier.
As usual, the blank identifier can never be referenced.
import _ "image/png" // register PNG decoder
This is known as a blank import. It is most often used to implement a compile-time mechanism whereby the main program can enable optional ...