-- Auto-generated for Macaulay2-1.25.11. Do not modify this file manually. --

                          Running Macaulay2 in Emacs

running Macaulay2 in Emacs
**************************

Because some answers can be very wide, it is a good idea to run Macaulay2 in a
window that does not wrap output lines and allows the user to scroll
horizontally to see the rest of the output.  We provide a package for "Emacs"
that implements this. It also provides for dynamic completion of symbols in the
language.

There is an ASCII version of this section of the documentation distributed in
the file share/emacs/site-lisp/macaulay2/M2-emacs-help.txt. It might be useful
for you to visit that file with Emacs now, thereby avoiding having to cut and
paste bits of text into Emacs buffers for the demonstrations below.

If you are a newcomer to Emacs, start up Emacs with the command emacs and then
start up the Emacs tutorial with the keystrokes "C-h t".  (The notation "C-h"
indicates that you should type "Ctrl-H", by holding down the "Ctrl" key, and
pressing "H".)  The Emacs tutorial will introduce you to the basic keystrokes
useful with Emacs.  After running through that you will want to examine the
online Emacs manual that can be read with info mode; you may enter or re-enter
that mode with the keystrokes "C-h i". You may also want to purchase (or print
out) the Emacs manual.  It is cheap, comprehensive and informative.  Once you
have spent an hour with the Emacs tutorial and manual, come back and continue
from this point.

We assume you have taught Emacs how to find Macaulay2's files, as described in
the previous sections, and that Emacs is loading the file M2-init.el
successfully.  Loading that file will cause Emacs to enter a special mode for
editing Macaulay2 code whenever a file whose name has the form *.m2 is
encountered.  It will also provide a special mode for running Macaulay2 in an
Emacs buffer.  It sets the variable transient-mark-mode to have a different
value in each buffer, and sets hooks so that transient-mark-mode will be set to
t in M2 buffers. The effect of this is that the mark is only active
occasionally, and then Emacs functions that act on a region of text will refuse
to proceed unless the mark is active.  The set-mark function or the
exchange-point-and-mark function will activate the mark, and it will remain
active until some change occurs to the buffer.  The only reason we recommend
the use of this mode is so the same key can be used to evaluate a line or a
region of code, depending on whether the region is active.

Exit and restart Emacs with your new initialization file. If you are reading
this file with Emacs, then use the keystrokes "C-x 2" to divide the buffer
containing this file into two windows. Then press the "M-x M2" to start up
Macaulay2 in a buffer named *M2*.  (The command line used to start Macaulay2
may be edited before being run if you use a prefix argument with the above
command: press "C-u" just before.)

If this doesn't start up Macaulay2, one reason may be that your function keys
are not operable.  In that case press "M-x M2" instead.  (The notation "M-x" is
Emacs notation for pressing the "x" key while holding down the "Meta" or "Alt"
key.)  If that doesn't work, please see "teaching Emacs how to find M2-init.el"
and "teaching Emacs how to find M2".

You may wish to bind the Emacs function M2-send-to-program to a global
keystroke for ease of use; this is done automatically in Macaulay2 buffers.
For example, the following Emacs code will bind it to the function key "F11".

(global-set-key [ f11 ] 'M2-send-to-program)

You may use "C-x o" freely to switch from one window to the other. Verify that
Macaulay2 is running by entering a command such as "2+2". Now paste the
following text into a buffer, unless you have the ASCII version of this
documentation in an Emacs buffer already, position the cursor on the first line
of code, and press the "F11" function key repeatedly to present each line to
Macaulay2.

i1 : R = ZZ/101[x,y,z]
i2 : f = symmetricPower(2,vars R)
i3 : M = cokernel f
i4 : C = resolution M
i5 : betti C

Notice that the input prompts are not submitted to Macaulay2.

Here is a way to conduct a demo of Macaulay2 in which the code to be submitted
is not visible on the screen.  Visit a file called foo.m2 and paste the
following text into it.

20!
4 + 5 * 2^20
-- that's all folks!

Press "M-f11" with your cursor in this buffer to designate it as the source for
the Macaulay2 commands.  (The notation "M-f11" means that while holding the
"Meta" key down, you should press the "F11" function key.  The "Meta" key is
the "Alt" key on some keyboards, or it can be simulated by pressing Escape
(just once) and following that with the key you wanted to press while the meta
key was held down.)  Then position your cursor (and thus the Emacs point)
within the line containing 20!.  Now press "M-x M2-demo" to open up a new frame
called DEMO for the *M2* window with a large font suitable for use with a
projector, and with your cursor in that frame, press "F11" a few times to
conduct the demo.  (If the font or frame is the wrong size, you may have to
create a copy of the file M2.el with a version of the function M2-demo modified
to fit your screen.)

One press of "F11" brings the next line of code forward into the *M2* buffer,
and the next press executes it.  Use "C-x 5 0" when you want the demo frame to
go away.

There is a way to send a region of text to Macaulay2: simply select a region of
text, making sure the mark is active (as described above) and press "F11". Try
that on the list below; put it into an Emacs buffer, move your cursor to the
start of the list, press "M-C-@" or "M-C-space" to mark the list, and then
press "F11" to send it to Macaulay2. (The notation "M-C-@" means: while holding
down the "Meta" key and the "Ctrl" key press the "@" key, for which you'll also
need the shift key.)

{a,b,c,d,e,f,
     g,h,i,j,k,l,
     m,n}

We have developed a system for incorporating Macaulay2 interactions into $\TeX$
files. Here is an example of how that looks. Paste the following text into an
Emacs buffer.

The answer, 4, is displayed after the output label ``{\tt o1\ =}''.
     Multiplication is indicated with the traditional {\tt *}.
     <<<1*2*3*4>>>
     Powers are obtained as follows.
     <<<2^100>>>

The bits in brackets can be submitted to Macaulay2 easily.  Position your
cursor at the top of the buffer and press "F10".  The cursor will move just
past the first <<<, and the Emacs mark will be positioned just before the >>>.
Thus 1*2*3*4 is the region, and it will even be highlighted if you have set the
Emacs variable transient-mark-mode to t for this buffer.  Pressing "F11" will
send 1*2*3*4 to Macaulay2 for execution: try it now. A sequence of such
Macaulay2 commands can be executed by alternately pressing "F10" and "F11". You
may also use "M-f10" to move backward to the previous bracketed expression.

Now go to the very end of the *M2* buffer with "M->" and experiment with
keyword completion. Type reso and then press the "TAB" key.  Notice how the
word is completed to resolution for you.  Delete the word with "M-DEL", type
res and then press the "TAB" key. The possible completions are displayed in a
window.  Switch to it with the "F8" key, move to the desired completion, press
the "Enter" key, and then return to the *M2* buffer with "C-x o".
Alternatively, if you have a mouse, use the middle button to select the desired
completion.

Experiment with command line history in the *M2* buffer.  Position your cursor
at the end of the buffer, and then use "M-p" and "M-n" to move to the previous
and next line of input remembered in the history.  When you get to one you'd
like to run again, simply press return to do so.  Or edit it slightly to change
it before pressing return.



-------------------------------------------------------------------------------

The source of this document is in Macaulay2Doc/ov_editors_emacs.m2:459:0.
