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C00002 00002	Some proposed new commands for E of the SWITCH_TO type. 
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Some proposed new commands for E of the SWITCH_TO type. 

     The  general philosophy is  that one  has a HOME  file that one  is
editing.  There may  be as many as 9 additional files that may be OPENed
(with LOOK-UP) and readily referenced at any one time.  One  may extract
lines of text  from these files via  the ATTACH buffer.   Pages of these
opened  files  may be  modified  during  the process  of  collecting the
information that is to be  gotten together but these modified  pages are
never  written  out so  that  these  files are  free  of  any danger  of
unintended alterations. One can further change the designated HOME  file
at any time so that one can alternate between  editing two or more files
but it will be  always clear as to which file one is editing.  Marks are
kept as  to one's location  in the  opened files  and one  automatically
returns to these locations on a simple command. When desired information
has  been collected into  the ATTACH buffer  one can return  to the HOME
file by a simple <CONTROL>H command and the ATTACH buffer will appear on
the screen above  the former CURRENT  line in the  HOME file and  can be
dealt  with as  desired.   Alternately,  one can  switch back  and forth
between two files, by  changing the HOME  file designation, and so  move
text back and forth between them, if this is, in fact, desired. 

    There is one problem with all of this.   In order for this scheme to
be convenient  to use, the type of  read-only reference provided  should
be such that  one would not  be continually  bothered with the  reminder
that one was in READONLY mode.  When one changed pages corrections would
just  go away. Of course,  if one forgot that one  was in this situation
and really wanted  to make the  changes then one  would be a bit  upset.
The solution seems to be that  the form of display must be such that one
is always aware  of this  limitation so  that one  does not  unwittingly
change pages and lose some desired corrections.   If one should suddenly
change  ones mind  after modifying  a  read-only page  and then  want to
preserve the  changes one  could  save the  situation by  attaching  the
entire page and then specifying the read-only file as the new HOME file,
depositing the  altered page and then deleting the old page.  This would
have to be done before a page change in the read-only file. 

    One proposed form of display would be to split the screen and show a
read-only page  above a dividing line with a few  lines of the HOME file
below as a reminder. This would also make it easier to keep in  mind the
intended  location for  the garnered  lines.   The limitation  would, of
course,  be the fact that one would not be  able to see quite as much of
the page  of the  read-only file.    On returning  to a  home file  this
portion of the screen would be expanded to resume it normal form. 

    It  is further intended  that the  information regarding  the opened
files will be kept on  the TMPCOR file as relating  to the HOME file  at
the time of exiting from E so that one can resume editing at some future
time with a minimum of inconvenience. 


The following commands are to be implemented. 

⊗O <file  name><cr> .   . Keep  the same HOME  file but OPEN  (and
                LOOK_UP)  the  designated  file  in  unchangeable,
                read-only, mode.  Files  so OPENed are assigned  a
                number,  automatically,  and  they  can  later  be
                referenced  by  this number  rather than  by name.
                OPENed files may be viewed page by  page and lines
                altered as long as  one stays on the same page but
                the altered  pages are  never  written out.    The
                ATTACH commands also work and  things put into the
                ATTACH  buffer remain  there  when one  leaves the
                file, always appearing just above the CURRENT line
                in the newly referenced file. 

⊗O#<cr> .  .  . Keep  the same HOME file but  OPEN  (actually only
                LOOK_UP)   the  file  that   had  previously  been
                referenced and  assigned the number  #.  The  last
                page formerly referenced will be displayed. 

⊗G<file name><cr> .  .  GO_TO (OPEN, LOOK_UP  and ENTER) the named
                file as  the new  HOME file  and assign  the  next
                available  number to  it.  This  file may  now  be
                altered as desired. 

⊗G#<cr>  .   .   .  GO_TO (actually  LOOK_UP  and ENTER)  the file
                previously assigned the number  # as the new  HOME
                file.  The default value  for # is 0 (the original
                HOME file). 

⊗H  .  .  .  .  Return to the HOME file at the former CURRENT line
                after visiting an OPEN file. 

⊗λ . .  .  . .  List the numbers that have been assigned with
                their associated file names as a memory refresher. 
                These appear in the scratch pad area at the bottom
                of the screen.