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spec: re-order built-ins sections alphabetically (more or less)

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Put the sections for the various built-ins into alphabetical order
based on the built-in name, while keeping built-ins that belong
together together.

The order is now (captialized letter determines order):

- Append
- Clear
- Close
- Complex, real, imag
- Delete
- Len, cap
- Make
- Min, max (to be inserted here)
- New
- Panic, recover
- Print, println

There are some white space adjustments but no changes to the prose
of the moved sections.

Change-Id: Iaec509918c6bc965df3f28656374de03279bdc9e
Reviewed-on: https://go-review.googlesource.com/c/go/+/498135
Reviewed-by: Robert Griesemer <gri@google.com>
TryBot-Bypass: Robert Griesemer <gri@google.com>
Reviewed-by: Ian Lance Taylor <iant@google.com>
This commit is contained in:
Robert Griesemer 2023-05-24 11:42:57 -07:00 committed by Robert Griesemer
parent 9b41418074
commit 15a4e0d970
1 changed files with 217 additions and 211 deletions
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@ -1,6 +1,6 @@
<!--{
"Title": "The Go Programming Language Specification",
"Subtitle": "Version of February 20, 2023",
"Subtitle": "Version of May 24, 2023",
"Path": "/ref/spec"
}-->
@ -7183,206 +7183,6 @@ so they can only appear in <a href="#Calls">call expressions</a>;
they cannot be used as function values.
</p>
<h3 id="Clear">Clear</h3>
<p>
The built-in function <code>clear</code> takes an argument of <a href="#Map_types">map</a>,
<a href="#Slice_types">slice</a>, or <a href="#Type_parameter_declarations">type parameter</a> type,
and deletes or zeroes out all elements.
</p>
<pre class="grammar">
Call Argument type Result
clear(m) map[K]T deletes all entries, resulting in an
empty map (len(m) == 0)
clear(s) []T sets all elements up to the length of
<code>s</code> to the zero value of T
clear(t) type parameter see below
</pre>
<p>
If the argument type is a <a href="#Type_parameter_declarations">type parameter</a>,
all types in its type set must be maps or slices, and <code>clear</code>
performs the operation corresponding to the actual type argument.
</p>
<p>
If the map or slice is <code>nil</code>, <code>clear</code> is a no-op.
</p>
<h3 id="Close">Close</h3>
<p>
For an argument <code>ch</code> with a <a href="#Core_types">core type</a>
that is a <a href="#Channel_types">channel</a>, the built-in function <code>close</code>
records that no more values will be sent on the channel.
It is an error if <code>ch</code> is a receive-only channel.
Sending to or closing a closed channel causes a <a href="#Run_time_panics">run-time panic</a>.
Closing the nil channel also causes a <a href="#Run_time_panics">run-time panic</a>.
After calling <code>close</code>, and after any previously
sent values have been received, receive operations will return
the zero value for the channel's type without blocking.
The multi-valued <a href="#Receive_operator">receive operation</a>
returns a received value along with an indication of whether the channel is closed.
</p>
<h3 id="Length_and_capacity">Length and capacity</h3>
<p>
The built-in functions <code>len</code> and <code>cap</code> take arguments
of various types and return a result of type <code>int</code>.
The implementation guarantees that the result always fits into an <code>int</code>.
</p>
<pre class="grammar">
Call Argument type Result
len(s) string type string length in bytes
[n]T, *[n]T array length (== n)
[]T slice length
map[K]T map length (number of defined keys)
chan T number of elements queued in channel buffer
type parameter see below
cap(s) [n]T, *[n]T array length (== n)
[]T slice capacity
chan T channel buffer capacity
type parameter see below
</pre>
<p>
If the argument type is a <a href="#Type_parameter_declarations">type parameter</a> <code>P</code>,
the call <code>len(e)</code> (or <code>cap(e)</code> respectively) must be valid for
each type in <code>P</code>'s type set.
The result is the length (or capacity, respectively) of the argument whose type
corresponds to the type argument with which <code>P</code> was
<a href="#Instantiations">instantiated</a>.
</p>
<p>
The capacity of a slice is the number of elements for which there is
space allocated in the underlying array.
At any time the following relationship holds:
</p>
<pre>
0 &lt;= len(s) &lt;= cap(s)
</pre>
<p>
The length of a <code>nil</code> slice, map or channel is 0.
The capacity of a <code>nil</code> slice or channel is 0.
</p>
<p>
The expression <code>len(s)</code> is <a href="#Constants">constant</a> if
<code>s</code> is a string constant. The expressions <code>len(s)</code> and
<code>cap(s)</code> are constants if the type of <code>s</code> is an array
or pointer to an array and the expression <code>s</code> does not contain
<a href="#Receive_operator">channel receives</a> or (non-constant)
<a href="#Calls">function calls</a>; in this case <code>s</code> is not evaluated.
Otherwise, invocations of <code>len</code> and <code>cap</code> are not
constant and <code>s</code> is evaluated.
</p>
<pre>
const (
c1 = imag(2i) // imag(2i) = 2.0 is a constant
c2 = len([10]float64{2}) // [10]float64{2} contains no function calls
c3 = len([10]float64{c1}) // [10]float64{c1} contains no function calls
c4 = len([10]float64{imag(2i)}) // imag(2i) is a constant and no function call is issued
c5 = len([10]float64{imag(z)}) // invalid: imag(z) is a (non-constant) function call
)
var z complex128
</pre>
<h3 id="Allocation">Allocation</h3>
<p>
The built-in function <code>new</code> takes a type <code>T</code>,
allocates storage for a <a href="#Variables">variable</a> of that type
at run time, and returns a value of type <code>*T</code>
<a href="#Pointer_types">pointing</a> to it.
The variable is initialized as described in the section on
<a href="#The_zero_value">initial values</a>.
</p>
<pre class="grammar">
new(T)
</pre>
<p>
For instance
</p>
<pre>
type S struct { a int; b float64 }
new(S)
</pre>
<p>
allocates storage for a variable of type <code>S</code>,
initializes it (<code>a=0</code>, <code>b=0.0</code>),
and returns a value of type <code>*S</code> containing the address
of the location.
</p>
<h3 id="Making_slices_maps_and_channels">Making slices, maps and channels</h3>
<p>
The built-in function <code>make</code> takes a type <code>T</code>,
optionally followed by a type-specific list of expressions.
The <a href="#Core_types">core type</a> of <code>T</code> must
be a slice, map or channel.
It returns a value of type <code>T</code> (not <code>*T</code>).
The memory is initialized as described in the section on
<a href="#The_zero_value">initial values</a>.
</p>
<pre class="grammar">
Call Core type Result
make(T, n) slice slice of type T with length n and capacity n
make(T, n, m) slice slice of type T with length n and capacity m
make(T) map map of type T
make(T, n) map map of type T with initial space for approximately n elements
make(T) channel unbuffered channel of type T
make(T, n) channel buffered channel of type T, buffer size n
</pre>
<p>
Each of the size arguments <code>n</code> and <code>m</code> must be of <a href="#Numeric_types">integer type</a>,
have a <a href="#Interface_types">type set</a> containing only integer types,
or be an untyped <a href="#Constants">constant</a>.
A constant size argument must be non-negative and <a href="#Representability">representable</a>
by a value of type <code>int</code>; if it is an untyped constant it is given type <code>int</code>.
If both <code>n</code> and <code>m</code> are provided and are constant, then
<code>n</code> must be no larger than <code>m</code>.
For slices and channels, if <code>n</code> is negative or larger than <code>m</code> at run time,
a <a href="#Run_time_panics">run-time panic</a> occurs.
</p>
<pre>
s := make([]int, 10, 100) // slice with len(s) == 10, cap(s) == 100
s := make([]int, 1e3) // slice with len(s) == cap(s) == 1000
s := make([]int, 1&lt;&lt;63) // illegal: len(s) is not representable by a value of type int
s := make([]int, 10, 0) // illegal: len(s) > cap(s)
c := make(chan int, 10) // channel with a buffer size of 10
m := make(map[string]int, 100) // map with initial space for approximately 100 elements
</pre>
<p>
Calling <code>make</code> with a map type and size hint <code>n</code> will
create a map with initial space to hold <code>n</code> map elements.
The precise behavior is implementation-dependent.
</p>
<h3 id="Appending_and_copying_slices">Appending to and copying slices</h3>
@ -7466,27 +7266,51 @@ n3 := copy(b, "Hello, World!") // n3 == 5, b is []byte("Hello")
</pre>
<h3 id="Deletion_of_map_elements">Deletion of map elements</h3>
<h3 id="Clear">Clear</h3>
<p>
The built-in function <code>delete</code> removes the element with key
<code>k</code> from a <a href="#Map_types">map</a> <code>m</code>. The
value <code>k</code> must be <a href="#Assignability">assignable</a>
to the key type of <code>m</code>.
The built-in function <code>clear</code> takes an argument of <a href="#Map_types">map</a>,
<a href="#Slice_types">slice</a>, or <a href="#Type_parameter_declarations">type parameter</a> type,
and deletes or zeroes out all elements.
</p>
<pre class="grammar">
delete(m, k) // remove element m[k] from map m
Call Argument type Result
clear(m) map[K]T deletes all entries, resulting in an
empty map (len(m) == 0)
clear(s) []T sets all elements up to the length of
<code>s</code> to the zero value of T
clear(t) type parameter see below
</pre>
<p>
If the type of <code>m</code> is a <a href="#Type_parameter_declarations">type parameter</a>,
all types in that type set must be maps, and they must all have identical key types.
If the argument type is a <a href="#Type_parameter_declarations">type parameter</a>,
all types in its type set must be maps or slices, and <code>clear</code>
performs the operation corresponding to the actual type argument.
</p>
<p>
If the map <code>m</code> is <code>nil</code> or the element <code>m[k]</code>
does not exist, <code>delete</code> is a no-op.
If the map or slice is <code>nil</code>, <code>clear</code> is a no-op.
</p>
<h3 id="Close">Close</h3>
<p>
For an argument <code>ch</code> with a <a href="#Core_types">core type</a>
that is a <a href="#Channel_types">channel</a>, the built-in function <code>close</code>
records that no more values will be sent on the channel.
It is an error if <code>ch</code> is a receive-only channel.
Sending to or closing a closed channel causes a <a href="#Run_time_panics">run-time panic</a>.
Closing the nil channel also causes a <a href="#Run_time_panics">run-time panic</a>.
After calling <code>close</code>, and after any previously
sent values have been received, receive operations will return
the zero value for the channel's type without blocking.
The multi-valued <a href="#Receive_operator">receive operation</a>
returns a received value along with an indication of whether the channel is closed.
</p>
@ -7558,6 +7382,187 @@ _ = imag(3 &lt;&lt; s) // illegal: 3 assumes complex type, can
Arguments of type parameter type are not permitted.
</p>
<h3 id="Deletion_of_map_elements">Deletion of map elements</h3>
<p>
The built-in function <code>delete</code> removes the element with key
<code>k</code> from a <a href="#Map_types">map</a> <code>m</code>. The
value <code>k</code> must be <a href="#Assignability">assignable</a>
to the key type of <code>m</code>.
</p>
<pre class="grammar">
delete(m, k) // remove element m[k] from map m
</pre>
<p>
If the type of <code>m</code> is a <a href="#Type_parameter_declarations">type parameter</a>,
all types in that type set must be maps, and they must all have identical key types.
</p>
<p>
If the map <code>m</code> is <code>nil</code> or the element <code>m[k]</code>
does not exist, <code>delete</code> is a no-op.
</p>
<h3 id="Length_and_capacity">Length and capacity</h3>
<p>
The built-in functions <code>len</code> and <code>cap</code> take arguments
of various types and return a result of type <code>int</code>.
The implementation guarantees that the result always fits into an <code>int</code>.
</p>
<pre class="grammar">
Call Argument type Result
len(s) string type string length in bytes
[n]T, *[n]T array length (== n)
[]T slice length
map[K]T map length (number of defined keys)
chan T number of elements queued in channel buffer
type parameter see below
cap(s) [n]T, *[n]T array length (== n)
[]T slice capacity
chan T channel buffer capacity
type parameter see below
</pre>
<p>
If the argument type is a <a href="#Type_parameter_declarations">type parameter</a> <code>P</code>,
the call <code>len(e)</code> (or <code>cap(e)</code> respectively) must be valid for
each type in <code>P</code>'s type set.
The result is the length (or capacity, respectively) of the argument whose type
corresponds to the type argument with which <code>P</code> was
<a href="#Instantiations">instantiated</a>.
</p>
<p>
The capacity of a slice is the number of elements for which there is
space allocated in the underlying array.
At any time the following relationship holds:
</p>
<pre>
0 &lt;= len(s) &lt;= cap(s)
</pre>
<p>
The length of a <code>nil</code> slice, map or channel is 0.
The capacity of a <code>nil</code> slice or channel is 0.
</p>
<p>
The expression <code>len(s)</code> is <a href="#Constants">constant</a> if
<code>s</code> is a string constant. The expressions <code>len(s)</code> and
<code>cap(s)</code> are constants if the type of <code>s</code> is an array
or pointer to an array and the expression <code>s</code> does not contain
<a href="#Receive_operator">channel receives</a> or (non-constant)
<a href="#Calls">function calls</a>; in this case <code>s</code> is not evaluated.
Otherwise, invocations of <code>len</code> and <code>cap</code> are not
constant and <code>s</code> is evaluated.
</p>
<pre>
const (
c1 = imag(2i) // imag(2i) = 2.0 is a constant
c2 = len([10]float64{2}) // [10]float64{2} contains no function calls
c3 = len([10]float64{c1}) // [10]float64{c1} contains no function calls
c4 = len([10]float64{imag(2i)}) // imag(2i) is a constant and no function call is issued
c5 = len([10]float64{imag(z)}) // invalid: imag(z) is a (non-constant) function call
)
var z complex128
</pre>
<h3 id="Making_slices_maps_and_channels">Making slices, maps and channels</h3>
<p>
The built-in function <code>make</code> takes a type <code>T</code>,
optionally followed by a type-specific list of expressions.
The <a href="#Core_types">core type</a> of <code>T</code> must
be a slice, map or channel.
It returns a value of type <code>T</code> (not <code>*T</code>).
The memory is initialized as described in the section on
<a href="#The_zero_value">initial values</a>.
</p>
<pre class="grammar">
Call Core type Result
make(T, n) slice slice of type T with length n and capacity n
make(T, n, m) slice slice of type T with length n and capacity m
make(T) map map of type T
make(T, n) map map of type T with initial space for approximately n elements
make(T) channel unbuffered channel of type T
make(T, n) channel buffered channel of type T, buffer size n
</pre>
<p>
Each of the size arguments <code>n</code> and <code>m</code> must be of <a href="#Numeric_types">integer type</a>,
have a <a href="#Interface_types">type set</a> containing only integer types,
or be an untyped <a href="#Constants">constant</a>.
A constant size argument must be non-negative and <a href="#Representability">representable</a>
by a value of type <code>int</code>; if it is an untyped constant it is given type <code>int</code>.
If both <code>n</code> and <code>m</code> are provided and are constant, then
<code>n</code> must be no larger than <code>m</code>.
For slices and channels, if <code>n</code> is negative or larger than <code>m</code> at run time,
a <a href="#Run_time_panics">run-time panic</a> occurs.
</p>
<pre>
s := make([]int, 10, 100) // slice with len(s) == 10, cap(s) == 100
s := make([]int, 1e3) // slice with len(s) == cap(s) == 1000
s := make([]int, 1&lt;&lt;63) // illegal: len(s) is not representable by a value of type int
s := make([]int, 10, 0) // illegal: len(s) > cap(s)
c := make(chan int, 10) // channel with a buffer size of 10
m := make(map[string]int, 100) // map with initial space for approximately 100 elements
</pre>
<p>
Calling <code>make</code> with a map type and size hint <code>n</code> will
create a map with initial space to hold <code>n</code> map elements.
The precise behavior is implementation-dependent.
</p>
<h3 id="Allocation">Allocation</h3>
<p>
The built-in function <code>new</code> takes a type <code>T</code>,
allocates storage for a <a href="#Variables">variable</a> of that type
at run time, and returns a value of type <code>*T</code>
<a href="#Pointer_types">pointing</a> to it.
The variable is initialized as described in the section on
<a href="#The_zero_value">initial values</a>.
</p>
<pre class="grammar">
new(T)
</pre>
<p>
For instance
</p>
<pre>
type S struct { a int; b float64 }
new(S)
</pre>
<p>
allocates storage for a variable of type <code>S</code>,
initializes it (<code>a=0</code>, <code>b=0.0</code>),
and returns a value of type <code>*S</code> containing the address
of the location.
</p>
<h3 id="Handling_panics">Handling panics</h3>
<p> Two built-in functions, <code>panic</code> and <code>recover</code>,
@ -7655,6 +7660,7 @@ accept arbitrary argument types, but printing of boolean, numeric, and string
<a href="#Types">types</a> must be supported.
</p>
<h2 id="Packages">Packages</h2>
<p>