For a full explanation of the motivation and design of Go 1, see XXX. Here follows a summary.
Go 1 is intended to be a stable language and core library set that will form a reliable foundation for people and organizations that want to make a long-term commitment to developing in the Go programming language. Go will continue to develop, but in a way that guarantees code written to the Go 1 specification will continue to work. For instance, Go 1 will be a supported platform on Google App Engine for the next few years. Incompatible changes to the environment, should they arise, will be done in a distinct version.
This document describes the changes in the language and libraries
in Go 1, relative to the previous release, r60 (at the time of
writing, tagged as r60.3). It also explains how to update code at
r60 to compile and run under Go 1. Finally, it outlines the new
go command for building Go programs and the new binary
release process being introduced. Most of these topics have more
thorough presentations elsewhere; such documents are linked below.
The original syntax for deleting an element in a map was:
m[x] = ignored, false
This syntax had a number of minor problems and is being replaced.
As of Go 1, that syntax is gone and in its place is a new built-in
function, delete. The call
will delete the map entry retrieved by the expression m[k].
There is no return value. Deleting a non-existent entry is a no-op.
Updating:
Gofix will convert expressions of the form m[k] = ignored,
false into delete(m, k) when it is clear that
the ignored value can be safely discarded from the program and
false refers to the predefined boolean constant. Gofix
will flag other uses of the syntax for inspection by the programmer.