<h3 id="Slice_expressions">Slice expressions</h3>

<p>
Slice expressions construct a substring or slice from a string, array, pointer
to array, or slice. There are two variants: a simple form that specifies a low
and high bound, and a full form that also specifies a bound on the capacity.
</p>

<h4>Simple slice expressions</h4>

<p>
For a string, array, pointer to array, or slice <code>a</code>, the primary expression

// A sparse file can be represented as either a sparseDatas or a sparseHoles.
// As long as the total size is known, they are equivalent and one can be
// converted to the other form and back. The various tar formats with sparse
// file support represent sparse files in the sparseDatas form. That is, they
// specify the fragments in the file that has data, and treat everything else as
// having zero bytes. As such, the encoding and decoding logic in this package

but guarantees never to return nil. If C's malloc indicates out of memory,
the helper function crashes the program, like when Go itself runs out
of memory. Because C.malloc cannot fail, it has no two-result form
that returns errno.

# C references to Go

Go functions can be exported for use by C code in the following way:

	//export MyFunction
	func MyFunction(arg1, arg2 int, arg3 string) int64 {...}

canonicalizing values (like "interning" or "hash-consing").

Any value of comparable type may be canonicalized with the new
`Make[T]` function, which produces a reference to a canonical copy of
the value in the form of a `Handle[T]`.
Two `Handle[T]` are equal if and only if the values used to produce the
handles are equal, allowing programs to deduplicate values and reduce
their memory footprint.

}
</pre>

<h4 id="General_interfaces">General interfaces</h4>

<p>
In their most general form, an interface element may also be an arbitrary type term
<code>T</code>, or a term of the form <code>~T</code> specifying the underlying type <code>T</code>,
or a union of terms <code>t<sub>1</sub>|t<sub>2</sub>|…|t<sub>n</sub></code>
[<a href="#Go_1.18">Go 1.18</a>].

// the last sent value is received. After the last value has been received
// from a closed channel c, any receive from c will succeed without
// blocking, returning the zero value for the channel element. The form
//
//	x, ok := <-c
//
// will also set ok to false for a closed and empty channel.
func close(c chan<- Type)

// The panic built-in function stops normal execution of the current

	}

	fw := &fileWriter{
		header: h,
		zipw:   w.cw,
	}
	w.last = fw
	return fw, nil
}

// Copy copies the file f (obtained from a [Reader]) into w. It copies the raw
// form directly bypassing decompression, compression, and validation.
func (w *Writer) Copy(f *File) error {
	r, err := f.OpenRaw()
	if err != nil {
		return err
	}