CS 227 lecture -*- Outline -*-

* working with emacs and scheme
	See the handout "How to Run Scheme"

	will show you 3 ways, the last of which is best,
		but others useful to know for other languages

** the hard way
	edit file in emacs
		% emacs
			C-x C-f
	quit emacs
			C-x C-c
	start scheme
		% scheme
			(load "file.ss")
	quit scheme
			C-d

	edit file in emacs...

** unix processes
	to Unix a process is the execution of a program (a task)
		 (like our series of steps)
	can have more than one around at a time

*** only one process taking input from your keyboard at a time
		this is the foreground process
	there may be other processes that are suspended
		not running but will pick up where they left off

*** an easier way
-----------
% scheme
...
C-z
% emacs
...
C-z
% fg %scheme
;back in scheme
(load "hw2b.ss")
>
...
C-z
%
------------
	C-z means typing control and at the same time z
		in scheme this echos as ^Z
	C-z suspends job, fg resumes it (puts in foreground)
	
	when scheme resumes, it doesn't prompt you again,
		but it is waiting for input
		you can type in a number, such as 7, and then return
			to see a prompt

	Don't forget to save your files before suspending emacs,
		scheme reads only the file on disk, not the emacs buffer
		a good way to save files in emacs is C-x s, and then
			answer y to the questions
	
	When you logout, you should properly exit emacs and scheme

*** the jobs command 
	the jobs command shows what processes you have suspended
		 (from your shell)
-----------
% scheme
...
C-z
% jobs
[1]  + Suspended	scheme
% emacs
...
C-x C-z
% jobs
[1]  - Suspended	scheme
[2]  + Suspended	emacs
% fg %scheme
;back in scheme
(load "anotherfile.ss")
>
...
C-z
% jobs
[1]  + Suspended	scheme
[2]  - Suspended	emacs
%
------------

	background processes given a job number (printed in square brackets)

	on fg command can use job number: fg %1
		or command name: fg %emacs
	leaving off argument resumes the + job: fg

** even easier (requires a workstation)
	open an emacs window, and run scheme in the vincent window
-----------
% emacs &
% scheme
>
...
-----------
	separate the windows so it's clear to which you're typing
		type scheme to the vincent prompt, not in emacs
	You MUST save your files before you load them into scheme,
		scheme reads only the file on disk, not the emacs buffer
	this will be a disaster if you're not on a workstation

** even easier using scheme mode in emacs
	M-x run-scheme

	will be using this in lectures...