if debug {
		assert(start <= pos && pos < end)
	}
	return posSpan{start, pos, end}
}

// spanOf extracts an error span from the given positioner. By default this is
// the trivial span starting and ending at pos, but this span is expanded when
// the argument naturally corresponds to a span of source code.
func spanOf(at positioner) posSpan {
	switch x := at.(type) {
	case nil:
		panic("nil positioner")
	case posSpan:

	if span.list != list {
		print("runtime: failed mSpanList.remove span.npages=", span.npages,
			" span=", span, " prev=", span.prev, " span.list=", span.list, " list=", list, "\n")
		throw("mSpanList.remove")
	}
	if list.first == span {
		list.first = span.next
	} else {
		span.prev.next = span.next
	}
	if list.last == span {
		list.last = span.prev
	} else {
		span.next.prev = span.prev

			"funcInfo.entry",

			// GC-related ones
			"cgoInRange",
			"gclinkptr.ptr",
			"guintptr.ptr",
			"heapBitsSlice",
			"markBits.isMarked",
			"muintptr.ptr",
			"puintptr.ptr",
			"spanOf",
			"spanOfUnchecked",
			"typePointers.nextFast",
			"(*gcWork).putFast",
			"(*gcWork).tryGetFast",
			"(*guintptr).set",
			"(*markBits).advance",
			"(*mspan).allocBitsForIndex",
			"(*mspan).base",

// small object spans and heap arena spans.
//
// Note that the uintptr of each element means something different for small object
// spans and for heap arena spans. Small object spans are easy: they're never interpreted
// as anything but uintptr, so they're immune to differences in endianness. However, the
// heapBits for user arena spans is exposed through a dummy type descriptor, so the byte

		if p == nil {
			throw("heapdump: out of memory")
		}
		tmpbuf = (*[1 << 30]byte)(p)[:n]
	}
	// Convert heap bitmap to pointer bitmap.
	clear(tmpbuf[:nptr/8+1])
	s := spanOf(p)
	tp := s.typePointersOf(p, size)
	for {
		var addr uintptr
		if tp, addr = tp.next(p + size); addr == 0 {
			break
		}
		i := (addr - p) / goarch.PtrSize
		tmpbuf[i/8] |= 1 << (i % 8)
	}

		rzSize := computeRZlog(span.elemsize)
		span.elemsize -= rzSize
		span.largeType.Size_ = span.elemsize
		rzStart := span.base() + span.elemsize
		span.userArenaChunkFree = makeAddrRange(span.base(), rzStart)
		asanpoison(unsafe.Pointer(rzStart), span.limit-rzStart)
		asanunpoison(unsafe.Pointer(span.base()), span.elemsize)
	}

	if rate := MemProfileRate; rate > 0 {
		c := getMCache(mp)
		if c == nil {

//   can free a whole span if none of the objects are marked, but that
//   isn't its goal. This can be driven either synchronously by
//   mcentral.cacheSpan for mcentral spans, or asynchronously by
//   sweepone, which looks at all the mcentral lists.
//
// * The span reclaimer looks for spans that contain no marked objects
//   and frees whole spans. This is a separate algorithm because

			// bottom of the signal stack. Fetch from there.
			// TODO: in efence mode, stack is sysAlloc'd, so this wouldn't
			// work.
			sp := getcallersp()
			s := spanOf(sp)
			if s != nil && s.state.get() == mSpanManual && s.base() < sp && sp < s.limit {
				gp := *(**g)(unsafe.Pointer(s.base()))
				return gp
			}
			return nil
		}
	}
	return getg()
}

		}

		// Check if val points to a heap span.
		span := spanOfHeap(val)
		if span == nil {
			continue
		}

		// Check if val points to an allocated object.
		idx := span.objIndex(val)
		if span.isFree(idx) {
			continue
		}

		// val points to an allocated object. Mark it.
		obj := span.base() + idx*span.elemsize
		greyobject(obj, b, i, span, gcw, idx)
	}
}

import com.google.common.base.Objects;

import java.io.Serializable;

public class Span implements Serializable {
    private final Style style;
    private final String text;

    public Span(Style style, String text) {
        this.style = style;
        this.text = text;
    }

    public Span(String text) {
        this(Style.NORMAL, text);
    }

    public Style getStyle() {