go/doc/go1.html

<!-- Go 1 Release Notes -->

<h2 id="introduction">Introduction to Go 1</h2>

<p>
For a full explanation of the motivation and design of Go 1, see XXX.
Here follows a summary.
</p>

<p>
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.
</p>

<p>
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
<code>go</code> 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.

<h2 id="language">Changes to the language</h2>

<h3 id="append">Append</h3>

<h3 id="close">Close</h3>

<h3 id="composite_literals">Composite literals</h3>

<h3 id="goroutines_init">Goroutines during init</h3>

<h3 id="rune">The rune type</h3>

<h3 id="map_deletion">Deleting from maps</h3>

<p>
The original syntax for deleting an element in a map was:
</p>

<pre>
    m[x] = ignored, false
</pre>

<p>
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, <code>delete</code>.  The call
</p>

<pre><!--{{code "progs/go1.go" `/delete\(m, k\)/`}}
-->    delete(m, k)
</pre>

<p>
will delete the map entry retrieved by the expression <code>m[k]</code>.
There is no return value. Deleting a non-existent entry is a no-op.
</p>

<p>
<em>Updating</em>:
Gofix will convert expressions of the form <code>m[k] = ignored,
false</code> into <code>delete(m, k)</code> when it is clear that
the ignored value can be safely discarded from the program and
<code>false</code> refers to the predefined boolean constant.  Gofix
will flag other uses of the syntax for inspection by the programmer.
</p>

<h3 id="map_iteration">Iterating in maps</h3>

<h3 id="multiple_assignment">Multiple assignment</h3>

<h3 id="shadowing">Returns and shadowed variables</h3>

<h3 id="struct_equality">Equality of structs and arrays</h3>

<h2 id="library">Changes to the library</h2>

<h3 id="package_hierarchy">The package hierarchy</h3>

<h3 id="errors">The error type</h3>

<h3 id="syscall_errors">System call errors</h3>

<h3 id="time">Time</h3>

<h3 id="html">The html package</h3>

<h3 id="http">The http package</h3>

<h3 id="strconv">The strconv package</h3>

<h3 id="exp">The package tree exp</h3>

<h3 id="old">The package tree old</h3>

<h3 id="deleted_packages">Deleted packages</h3>

<!-- 
go/typechecker
go/types
ebnf (and cmd/ebnflint)
container/vector
try (and gotry)
exp/datafmt
netchan
-->

<h3 id="subrepo_packages">Packages moving to subrepositories</h3>

<!-- 
crypto/openpgp to XXX
maybe exp/ssh?
-->

<h3 id="os_fileinfo">The os.FileInfo type</h3>

<h2 id="go_command">The go command</h2>

<h2 id="releases">Packaged releases</h2>