document_range is a pair of document_position objects,
with each position indicating the start and end of the range,
respectively.document_range(start, end = NULL)is.document_range(x)
as.document_range(x)
document_position indicating the start of the
range.document_position indicating the end of the range.document_range.list with class document_range and fields:
start: |
| The start position. |
end: |
| The end position. |