COMMENT ⊗   VALID 00002 PAGES
C REC  PAGE   DESCRIPTION
C00001 00001
C00002 00002	Description
C00006 ENDMK
C⊗;
Description

	Essay is  a modified version  of ETV, the  editor.  It  is an
experimental  document  retrieval  system.   It  allows  the user  to
comment on his readings, read  other user's comments, and read  other
text files referenced by a document. 
	Its operation is based on the file switching system, modified
to  behave  like  a  push  down  stack.    Commands which  switch  to
references and comments save the  state of the screen (name of  file,
page number,  line number, etc.) on  the stack.  The  user may at any
time  'POPJ' to return to a previous  state, or random access entries
on the stack. 


Operation
	<CTRL><META>π is  the  'PUSHJ' command.   It  scans the  page
(starting  at the current  line) for  a file name  or a pointer  to a
comment.  A file name is anything of the appropriate form including a
PPN.   A comment  pointer looks  like "(Comment here  by SGK  on page
69.)".   If a file name or comment pointer is found, the state of the
world is 'Pushed' onto the stack, and the comment  or file referenced
is displayed. 
	<CTRL><META>G is the 'POPJ' command.  It undoes the effect of
a  <CTRL><META>π, bringing  the user  back one entry  in his  list of
pushed states. 
	<CTRL><META>∀ is the  comment command.  It saves  the current
state on  the stack, and creates  a new page in  the file being read.
The user is expected to type (edit) an intelligent comment, then type
<CTRL><META>G which  saves the comment,  and returns the user  to the
place where he typed <CTRL><META>∀. 


	<CTRL>π is  like  the <CTRL>ε  command in  E  except that  it
treats the  file switching data structure like  a push down stack (as
do other Essay  commands) This means  you can  return from a  <CTRL>π
with  a <CTRL><META>G,  and is  otherwise compatable  with the  Essay
stack. 

Other commands that are useful to know about are:

	<CTRL>∃	Displays the stack including stale entries
	<CTRL>λ	Switches to a new file, or can be used to random access
		entries on the stack


Notes to authors:
If you want your document to be readable thru Essay, have it formated
for E, and put it on the [XXX,DOC] area.  When you want to reference
another file in your document that is on the system, make sure that
the file name includes a PPN and page and line numbers.  A typical
reference might look like this: "(See ESSAY.SGK[UP,DOC](2P69L) for
details.)".