• Create BookmarkCreate Bookmark
  • Create Note or TagCreate Note or Tag
  • PrintPrint
Share this Page URL
Help

Chapter Five. Unification > Cursor Design and a Strategy for Making Selections

5-5. Cursor Design and a Strategy for Making Selections

The traditional intent of both delimited- and incremental-string searches is to find and to select a target string in the text. Patterns that people use in searches tend to be short because long patterns are tedious to type and, in most systems, must be accurate to the character if they are to match the target. Therefore, string searches typically are not used to select even moderately large targets—say, those greater than 10 or 15 characters in length—much less truly large blocks of text. One application of string searches is to help you find the location of a desired selection, after which you use another technique, such as using a GID to drag from one end of the selection to the other, to establish the selection. However, if the ends of the selection are not visible simultaneously, you must use another strategy. The strategy consists of (1) marking one end of the selection, with the method of marking depending on the system being used; (2) using such facilities as scroll bars to make the other end of the selection visible; and (3) marking the other end of the selection. In most systems, marking the second end of the selection establishes the desired selection.

A more efficient approach is to design the search mechanism such that it positions the cursor on a particular character. Two such positionings can be used to define the first and last characters of a selection. The multiplicity of mechanisms conventionally needed to find the ends of a selection—cursor motion, scrolling, various page and pattern find facilities, and so on—and to mark them are replaced with one mechanism used twice, making learning, operation, and habituation easier and simplifying the implementation.


PREVIEW

                                                                          

Not a subscriber?

Start A Free Trial


  
  • Creative Edge
  • Create BookmarkCreate Bookmark
  • Create Note or TagCreate Note or Tag
  • PrintPrint