// it has sufficient capacity, the destination is resliced to accommodate the
// new elements. If it does not, a new underlying array will be allocated.
// Append returns the updated slice. It is therefore necessary to store the
// result of append, often in the variable holding the slice itself:
//
//	slice = append(slice, elem1, elem2)
//	slice = append(slice, anotherSlice...)
//

// Fields interprets s as a sequence of UTF-8-encoded code points.
// It splits the slice s around each instance of one or more consecutive white space
// characters, as defined by unicode.IsSpace, returning a slice of subslices of s or an
// empty slice if s contains only white space.
func Fields(s []byte) [][]byte {
	// First count the fields.
	// This is an exact count if s is ASCII, otherwise it is an approximation.

// a byte slice.
// Unlike a [Buffer], a Reader is read-only and supports seeking.
// The zero value for Reader operates like a Reader of an empty slice.
type Reader struct {
	s        []byte
	i        int64 // current reading index
	prevRune int   // index of previous rune; or < 0
}

// Len returns the number of bytes of the unread portion of the
// slice.
func (r *Reader) Len() int {

The [Repeat] function returns a new slice that repeats the

The <i>capacity</i> is a measure of that extent: it is the sum of
the length of the slice and the length of the array beyond the slice;
a slice of length up to that capacity can be created by
<a href="#Slice_expressions"><i>slicing</i></a> a new one from the original slice.
The capacity of a slice <code>a</code> can be discovered using the
built-in function <a href="#Length_and_capacity"><code>cap(a)</code></a>.

}

func lookup(args []string, arg string) int {
	for i, a := range args {
		if a == arg {
			return i
		}
	}
	return -1
}

// invokeMacro pushes onto the input Stack a Slice that holds the macro definition with the actual
// parameters substituted for the formals.
// Invoking a macro does not touch the PC/line history.
func (in *Input) invokeMacro(macro *Macro) {

	nesting := 0
	colon := -1
	for tok != '\n' && tok != ';' {
		// Process one operand.
		var items []lex.Token
		if cap(operands) > len(operands) {
			// Reuse scratch items slice.
			items = operands[:cap(operands)][len(operands)][:0]
		} else {
			items = make([]lex.Token, 0, 3)
		}
		for {
			tok = p.nextToken()
			if len(operands) == 0 && len(items) == 0 {

pkg reflect, const SelectRecv = 2
pkg reflect, const SelectRecv SelectDir
pkg reflect, const SelectSend = 1
pkg reflect, const SelectSend SelectDir
pkg reflect, const SendDir = 2
pkg reflect, const Slice = 23
pkg reflect, const String = 24
pkg reflect, const Struct = 25
pkg reflect, const Uint = 7
pkg reflect, const Uint16 = 9
pkg reflect, const Uint32 = 10
pkg reflect, const Uint64 = 11

//go:linkname runtime_arena_arena_New
func runtime_arena_arena_New(arena unsafe.Pointer, typ any) any

// Mark as noescape to avoid escaping the slice header.
//
//go:noescape
//go:linkname runtime_arena_arena_Slice
func runtime_arena_arena_Slice(arena unsafe.Pointer, slice any, cap int)

//go:linkname runtime_arena_arena_Free
func runtime_arena_arena_Free(arena unsafe.Pointer)

//go:linkname runtime_arena_heapify

// scanning lines, a [SplitFunc] can return (0, nil, nil) to signal the
// [Scanner] to read more data into the slice and try again with a
// longer slice starting at the same point in the input.
//
// The function is never called with an empty data slice unless atEOF
// is true. If atEOF is true, however, data may be non-empty and,
// as always, holds unprocessed text.