Rob Pike: Play It Again, Sam

[croft at su-safe.ARPA]

From: Bill Croft <croft at su-safe.ARPA>

                          PIXELS AND PREDICATES
       Sam: A Text Editor Based on Structural Regular Expressions
                           Rob Pike, Bell Labs
                 1:00 pm, Monday, March 3, CSLI trailers
     (This meeting is Monday not Wednesday, the usual meeting date)

        This talk will assume some familiarity with the `cut and paste'
   model of editing supported by the mouse interface, and will focus on
   the command language.
      `Sam' has two interfaces: a mouse-based language very similar to
   `jim'(9.1), and a command language reminiscent of `ed'(1).  `Sam' is
   based on `structural regular expressions': the application of regular
   expressions to describe the form of a file.  Conventional Unix tools
   think of their input as arrays of lines.  The new notation makes it
   easy to make changes to files regardless of their structure, to define
   structure within the elements (e.g., the pieces of a line), and to
   change the apparent shape of a file according to the change being
   made.
      The use of structural regular expressions makes it possible for the
   mouse and command languages to operate on the same objects, so that
   editing commands from the mouse and keyboard may be mixed comfortably
   and effectively.  Of course, either mouse or keyboard may be used
   exclusively of the other, so `sam' can be used as if it were `jim',
   `ed' or even `sed'---a `stream' version of `sam' is forthcoming.