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Comparison of Edwin to Emacs

This section documents known differences between Edwin 3.90 and Emacs 18.57. A reference to a "documented" feature of Emacs means that the feature is documented in the GNU Emacs version 18 manual.

Incompatibilities

These are differences in design, unlikely to be `fixed'.

Edwin's keyboard character set is a superset of Emacs'. Edwin has support for real MIT-style bucky bits. Under X windows and OS/2 (and perhaps other systems) Edwin can distinguish between C-a and C-A, C-SPC and C-@, etc. When running on a terminal, the input set is limited to 8-bit ASCII as in Emacs.
Edwin is case-insensitive for command and variable names.
Edwin additionally defines C-z and C-^ as prefix keys. C-z is the CTRL-META prefix, and C-^ is the CTRL prefix, both as in TOPS-20 Emacs.
C-z doesn't suspend Edwin. C-x C-z suspends both Emacs and Edwin, but isn't defined in the Emacs Manual. Under X, Emacs produces an error message when C-x C-z is typed; Edwin suspends itself if it was started from a shell with job control, otherwise it dies.
C-h f doesn't work for anything but editor commands, i.e. it only documents editor commands, not ordinary Scheme procedures like car or call-with-current-continuation.
C-h v doesn't work for anything but editor variables, i.e. it only documents editor variables, not ordinary Scheme variables.
In Edwin, C-w and C-y don't skip to next occurrence in reverse i-search. This is intentional, and matches the behavior of Emacs 19.
comment-indent-hook is defined differently. In Emacs, it is called with no arguments and with point at the beginning of the comment; in Edwin, it is called with a single argument, the mark at the beginning of the comment, and with point undefined.
Edwin's completion of Scheme variables is dependent on the environment. In Scheme and Scheme Interaction modes, M-TAB completes the Scheme variable name. Completion is environment-dependent, so a prefix may complete differently (or not at all) in two different buffers with different associated environments.
M-x load-file and M-x load-library behave somewhat differently in Edwin.
The evaluation commands are much different in Edwin.
Edwin doesn't recognize `Local Variables:' at the end of a file; instead it recognizes `Edwin Variables:'. This is done because it cannot support the full syntax of Emacs local variables.
Variable text-mode-hook is an event distributor rather than a procedure of no arguments.

Deficiencies

Deficiencies are shortcomings of Edwin that are likely to be fixed.

C-x ^ can be used to grow or shrink the minibuffer window in Emacs but not in Edwin.

C-h in Edwin is a subset of that in Emacs. Missing subcommands:

n   view-emacs-news
c-c describe-copying
c-d describe-distribution
c-w describe-warranty

Dired is missing these commands in Edwin: v and B.
C-x n is not disabled by default.
Edwin does not have the notion of "novice".

Missing Subsystems

The following documented subsystems are implemented by Emacs but not by Edwin.

abbrev mode (edwin has dynamic abbreviations)
emulation modes: edt, vi, vip
file locks
language modes: emacs-lisp, fortran, lisp, modula-2, prolog
overwrite mode
picture mode
slow terminal incremental search
spelling
tab stops
text formatter modes: nroff, scribe, tex, latex

These commands are implemented by Emacs but not by Edwin. The commands marked with an asterisk are implemented under Unix and OS/2 but not under Windows. Some of the asterisked commands can work under Windows but the code to implement them is not loaded in order to save space; others are require subprocess support that isn't available in the Windows implementation.

  abbrev-mode
  abbrev-prefix-mark
  add-change-log-entry
  add-change-log-entry-other-window
  add-global-abbrev
  add-mode-abbrev
  add-name-to-file
  append-to-buffer
  byte-compile-file
  byte-recompile-directory
  cancel-debug-on-entry
* compile
  convert-mocklisp-buffer
  copy-to-buffer
  debug-on-entry
  define-abbrevs
* delete-matching-lines
* delete-non-matching-lines
  describe-copying
  describe-distribution
  describe-no-warranty
  describe-syntax
  disable-command
  disassemble
  display-time                          (run-notifier is similar)
  dissociated-press
  doctor
  edit-abbrevs
  edit-abbrevs-redefine
  edit-options
  edit-picture
  edit-tab-stops
  edit-tab-stops-note-changes
  edt-emulation-on
  emacs-lisp-mode
  emacs-version
  enable-command
  expand-abbrev
  expand-region-abbrevs
  flush-lines
  fortran-mode
  global-set-key                        (set-key is similar)
  grep
  hanoi
  indent-c-exp                          c-indent-expression
  insert-abbrevs
  insert-kbd-macro                      write-kbd-macro
  insert-parentheses
  inverse-add-global-abbrev
  inverse-add-mode-abbrev
* keep-lines
  kill-all-abbrevs
  latex-mode                            Note: BAL has one
  lisp-complete-symbol                  (scheme-complete-variable is similar)
  lisp-interaction-mode                 (inferior-repl-mode is similar)
  lisp-mode
  lisp-send-defun
  list-abbrevs
  list-command-history
  list-options
  list-tags
  local-set-key
* lpr-buffer
* lpr-region
  make-symbolic-link
  make-variable-buffer-local
* manual-entry
  modify-syntax-entry
  move-past-close-and-reindent
  next-error
  next-file
  nroff-mode
* occur
* occur-mode-goto-occurrence
  open-dribble-file
  open-termscript
  overwrite-mode
  plain-tex-mode
  prepend-to-buffer
* print-buffer
* print-region
  read-abbrev-file
  recover-file
  run-lisp
  save-buffers-kill-emacs               save-buffers-kill-scheme
  set-gosmacs-bindings
* shell-command
* shell-command-on-region
  spell-buffer
  spell-region
  spell-string
  spell-word
  suspend-emacs                         suspend-scheme
  tab-to-tab-stop
  tags-apropos
  tex-mode
  top-level
  unexpand-abbrev
  vi-mode
  view-buffer
  view-emacs-news
  view-file
  vip-mode
  write-abbrev-file
  yow
  zap-to-char

Missing Variables

These documented variables are implemented by Emacs but not Edwin. The variables marked with an asterisk are implemented under Unix and OS/2, but not under Windows.

  abbrev-all-caps
  abbrev-file-name
  blink-matching-paren
  blink-matching-paren-distance
  buffer-read-only
  c-tab-always-indent
  comment-start-skip
* compile-command
  completion-ignore-case                (not documented)
  ctl-arrow
  debug-on-error                        debug-on-editor-error
                                        debug-on-internal-error
                                        debug-on-evaluation-error
                                        are similar, but more specific
  debug-on-quit
  default-directory
  default-major-mode
  echo-keystrokes
  initial-major-mode                    Scheme variable initial-buffer-mode
  insert-default-directory
  inverse-video
  kill-ring-max
  load-path
* lpr-switches
  major-mode
  mark-ring
  mark-ring-max                         mark-ring-maximum
  meta-flag
  no-redraw-on-recenter
  save-abbrevs
  selective-display-ellipses
* shell-file-name
  tab-stop-list
  tags-file-name                        (tags-table-pathname is similar)
  track-eol
  visible-bell

Per-Buffer Variables

These documented variables are per-buffer in Emacs but not in Edwin.

abbrev-mode
auto-fill-hook
buffer-auto-save-file-name
buffer-backed-up
buffer-file-name
buffer-offer-save
buffer-read-only
buffer-saved-size
buffer-undo-list
ctl-arrow
default-directory
local-abbrev-table
major-mode
mark-ring
mode-name
overwrite-mode
selective-display
selective-display-ellipses
shell-prompt-pattern

Edwin Bugs

Incorrect behavior of Edwin that will be fixed:

Negative argument to M-u, M-l, and M-c seems to work by accident.
`-*- foo -*-' is valid if preceded only by blank lines; in Edwin this works only if it is on a file's the first line.
Closing paren doesn't check for mismatched delimiters and issue warning message. In c-mode, `]' isn't treated specially, and don't flash the matching delimiter.
C-u C-x ; isn't handled right in Edwin.
M-x indent-for-comment shouldn't reindent existing comment in column zero.

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