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| -rw-r--r-- | doc/go_spec.html | 41 |
1 files changed, 34 insertions, 7 deletions
diff --git a/doc/go_spec.html b/doc/go_spec.html index 2238cb39fd..88b2a68057 100644 --- a/doc/go_spec.html +++ b/doc/go_spec.html @@ -1,6 +1,6 @@ <!--{ "Title": "The Go Programming Language Specification", - "Subtitle": "Language version go1.27 (April 1, 2026)", + "Subtitle": "Language version go1.27 (April 7, 2026)", "Path": "/ref/spec" }--> @@ -1294,6 +1294,8 @@ those methods, and the corresponding <a href="#Method_sets">method set</a> consi exactly of the methods specified by the interface. Interfaces whose type sets can be defined entirely by a list of methods are called <i>basic interfaces.</i> +Interface methods cannot declare <a href="#Type_parameter_declarations">type parameters</a>, +but they may use type parameters from the interface declaration. </p> <pre> @@ -2625,11 +2627,11 @@ func (l *List[T]) Len() int { … } <h3 id="Type_parameter_declarations">Type parameter declarations</h3> <p> -A type parameter list declares the <i>type parameters</i> of a generic function or type declaration. +A type parameter list declares the <i>type parameters</i> of a generic function, method, or type declaration. The type parameter list looks like an ordinary <a href="#Function_types">function parameter list</a> except that the type parameter names must all be present and the list is enclosed in square brackets rather than parentheses -[<a href="#Go_1.18">Go 1.18</a>]. +[<a href="#Go_1.18">Go 1.18</a>, <a href="#Go_1.27">Go 1.27</a>]. </p> <pre class="ebnf"> @@ -2643,7 +2645,7 @@ All non-blank names in the list must be unique. Each name declares a type parameter, which is a new and different <a href="#Types">named type</a> that acts as a placeholder for an (as of yet) unknown type in the declaration. The type parameter is replaced with a <i>type argument</i> upon -<a href="#Instantiations">instantiation</a> of the generic function or type. +<a href="#Instantiations">instantiation</a> of the generic function, method, or type. </p> <pre> @@ -2978,7 +2980,7 @@ and associates the method with the receiver's <i>base type</i>. </p> <pre class="ebnf"> -MethodDecl = "func" Receiver MethodName Signature [ FunctionBody ] . +MethodDecl = "func" Receiver MethodName [ TypeParameters ] Signature [ FunctionBody ] . Receiver = Parameters . </pre> @@ -3071,6 +3073,27 @@ func (HPoint) Draw(P) { … } // illegal: alias must not denote instantia func (*IPair) Second() int { … } // illegal: alias must not denote instantiated type Pair[int, int] </pre> +<p> +If the method declaration specifies <a href="#Type_parameter_declarations">type parameters</a> +(possibly in addition to type parameters declared by the receiver specification), the method name denotes +a <i>generic method</i>. +Like a generic function, a generic method must be <a href="#Instantiations">instantiated</a> before it can +be called or used as a value. +</p> + +<pre> +type List[E any] []E + +// Apply returns the list obtained from applying f to each element of l. +func (l List[E]) Apply[F any](f func(E) F) List[F] { + r := make(List[F], len(l)) + for i, x := range l { + r[i] = f(x) + } + return r +} +</pre> + <h2 id="Expressions">Expressions</h2> <p> @@ -4354,7 +4377,7 @@ with the same underlying array. <h3 id="Instantiations">Instantiations</h3> <p> -A generic function or type is <i>instantiated</i> by substituting <i>type arguments</i> +A generic function, method, or type is <i>instantiated</i> by substituting <i>type arguments</i> for the type parameters [<a href="#Go_1.18">Go 1.18</a>]. Instantiation proceeds in two steps: </p> @@ -4376,7 +4399,7 @@ of the corresponding type parameter. Otherwise instantiation fails. <p> Instantiating a type results in a new non-generic <a href="#Types">named type</a>; -instantiating a function produces a new non-generic function. +instantiating a function or method produces a new non-generic function or method. </p> <pre> @@ -8807,6 +8830,10 @@ An <a href="#Alias_declarations">alias declaration</a> may declare <h4 id="Go_1.27">Go 1.27</h4> <ul> <li> +A <a href="#Method_declarations">method declaration</a> may declare +<a href="#Type_parameter_declarations">type parameters</a>. +</li> +<li> A key in a struct <a href="#Composite_literals">composite literal</a> may be any valid field <a href="#Selectors">selector</a> for the struct type, not just a (top-level) field name of the struct. |