pkg go/build/constraint, method (*AndExpr) Eval(func(string) bool) bool
pkg go/build/constraint, method (*AndExpr) String() string
pkg go/build/constraint, method (*NotExpr) Eval(func(string) bool) bool
pkg go/build/constraint, method (*NotExpr) String() string
pkg go/build/constraint, method (*OrExpr) Eval(func(string) bool) bool
pkg go/build/constraint, method (*OrExpr) String() string

</pre>

<p>
Although the examples above use non-interface types, it is also legal to create a method value
from a value of interface type.
</p>

<pre>
var i interface { M(int) } = myVal
f := i.M; f(7)  // like i.M(7)
</pre>


<h3 id="Index_expressions">Index expressions</h3>

<p>
A primary expression of the form
</p>

<pre>
a[x]
</pre>

<p>