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456 lines
16 KiB
EmacsLisp
456 lines
16 KiB
EmacsLisp
;;; ielm.el --- interaction mode for Emacs Lisp
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;; Copyright (C) 1994 Free Software Foundation, Inc.
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;; Author: David Smith <maa036@lancaster.ac.uk>
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;; Created: 25 Feb 1994
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;; Keywords: lisp
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;; This file is part of GNU Emacs.
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;; GNU Emacs is free software; you can redistribute it and/or modify
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;; it under the terms of the GNU General Public License as published by
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;; the Free Software Foundation; either version 2, or (at your option)
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;; any later version.
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;; GNU Emacs is distributed in the hope that it will be useful,
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;; but WITHOUT ANY WARRANTY; without even the implied warranty of
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;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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;; GNU General Public License for more details.
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;; You should have received a copy of the GNU General Public License
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;; along with GNU Emacs; see the file COPYING. If not, write to
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;; the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.
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;;; Commentary:
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;; Provides a nice interface to evaluating Emacs Lisp expressions.
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;; Input is handled by the comint package, and output is passed
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;; through the pretty-printer.
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;; To install: copy this file to a directory in your load-path, and
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;; add the following line to your .emacs file:
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;;
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;; (autoload 'ielm "ielm" "Start an inferior Emacs Lisp session" t)
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;;
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;; For completion to work, the comint.el from FSF Emacs 19.23 is
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;; required. If you do not have it, or if you are running Lemacs,
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;; also add the following code to your .emacs:
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;;
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;; (setq ielm-mode-hook
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;; '(lambda nil
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;; (define-key ielm-map "\t"
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;; '(lambda nil (interactive) (or (ielm-tab)
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;; (lisp-complete-symbol))))))
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;; To start: M-x ielm. Type C-h m in the *ielm* buffer for more info.
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;; The latest version is available by WWW from
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;; http://mathssun5.lancs.ac.uk:2080/~maa036/elisp/dir.html
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;; or by anonymous FTP from
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;; /anonymous@wingra.stat.wisc.edu:pub/src/emacs-lisp/ielm.el.gz
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;; or from the author: David M. Smith <maa036@lancaster.ac.uk>
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;;; Code:
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(require 'comint)
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(require 'pp)
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;;; User variables
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(defvar ielm-noisy t
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"*If non-nil, IELM will beep on error.")
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(defvar ielm-prompt "ELISP> "
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"Prompt used in IELM.")
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(defvar ielm-dynamic-return t
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"*Controls whether \\<ielm-map>\\[ielm-return] has intelligent behaviour in IELM.
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If non-nil, \\[ielm-return] evaluates input for complete sexps, or inserts a newline
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and indents for incomplete sexps. If nil, always inserts newlines.")
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(defvar ielm-dynamic-multiline-inputs t
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"*Force multiline inputs to start from column zero?
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If non-nil, after entering the first line of an incomplete sexp, a newline
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will be inserted after the prompt, moving the input to the next line.
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This gives more frame width for large indented sexps, and allows functions
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such as `edebug-defun' to work with such inputs.")
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(defvar ielm-mode-hook nil
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"*Hooks to be run when IELM (`inferior-emacs-lisp-mode') is started.")
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;;; System variables
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(defvar ielm-working-buffer nil
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"Buffer in which IELM sexps will be evaluated.
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This variable is buffer-local.")
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(defvar ielm-header
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(concat
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"*** Welcome to IELM version "
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(substring "$Revision: 1.2 $" 11 -2)
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" *** Type (describe-mode) for help.\n"
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"IELM has ABSOLUTELY NO WARRANTY; type (describe-no-warranty) for details.\n")
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"Message to display when IELM is started.")
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(defvar ielm-map nil)
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(if ielm-map nil
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(if (string-match "Lucid" emacs-version)
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;; Lemacs
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(progn
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(setq ielm-map (make-sparse-keymap))
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(set-keymap-parent ielm-map comint-mode-map))
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;; FSF
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(setq ielm-map (cons 'keymap comint-mode-map)))
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(define-key ielm-map "\t" 'comint-dynamic-complete)
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(define-key ielm-map "\C-m" 'ielm-return)
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(define-key ielm-map "\C-j" 'ielm-send-input)
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(define-key ielm-map "\e\C-x" 'eval-defun) ; for consistency with
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(define-key ielm-map "\e\t" 'lisp-complete-symbol) ; lisp-interaction-mode
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;; These bindings are from shared-lisp-mode-map -- can you inherit
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;; from more than one keymap??
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(define-key ielm-map "\e\C-q" 'indent-sexp)
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(define-key ielm-map "\eq" 'lisp-fill-paragraph)
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(define-key ielm-map "\177" 'backward-delete-char-untabify)
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;; Some convenience bindings for setting the working buffer
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(define-key ielm-map "\C-c\C-b" 'ielm-change-working-buffer)
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(define-key ielm-map "\C-c\C-f" 'ielm-display-working-buffer)
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(define-key ielm-map "\C-c\C-v" 'ielm-print-working-buffer))
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;;; Completion stuff
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(defun ielm-tab nil
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"Possibly indent the current line as lisp code."
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(interactive)
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(if (or (eq (preceding-char) ?\n)
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(eq (char-syntax (preceding-char)) ? ))
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(progn
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(ielm-indent-line)
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t)))
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(defun ielm-complete-symbol nil
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"Complete the lisp symbol before point."
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;; A wrapper for lisp-complete symbol that returns non-nil if
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;; completion has occurred
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(let* ((btick (buffer-modified-tick))
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(cbuffer (get-buffer "*Completions*"))
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(ctick (and cbuffer (buffer-modified-tick cbuffer))))
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(lisp-complete-symbol)
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;; completion has occurred if:
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(or
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;; the buffer has been modified
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(not (= btick (buffer-modified-tick)))
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;; a completions buffer has been modifed or created
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(if cbuffer
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(not (= ctick (buffer-modified-tick cbuffer)))
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(get-buffer "*Completions*")))))
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(defun ielm-complete-filename nil
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"Dynamically complete filename before point, if in a string."
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(if (nth 3 (parse-partial-sexp comint-last-input-start (point)))
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(comint-dynamic-complete-filename)))
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(defun ielm-indent-line nil
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"Indent the current line as Lisp code if it is not a prompt line."
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(if (save-excursion
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(beginning-of-line)
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(looking-at comint-prompt-regexp)) nil
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(lisp-indent-line)))
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;;; Working buffer manipulation
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(defun ielm-print-working-buffer nil
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"Print the current IELM working buffer's name in the echo area."
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(interactive)
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(message "The current working buffer is: %s" (buffer-name ielm-working-buffer)))
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(defun ielm-display-working-buffer nil
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"Display the current IELM working buffer.
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Don't forget that selecting that buffer will change its value of `point'
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to its value of `window-point'!"
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(interactive)
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(display-buffer ielm-working-buffer)
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(ielm-print-working-buffer))
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(defun ielm-change-working-buffer (buf)
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"Change the current IELM working buffer to BUF.
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This is the buffer in which all sexps entered at the IELM prompt are
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evaluated. You can achieve the same effect with a call to
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`set-buffer' at the IELM prompt."
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(interactive "bSet working buffer to: ")
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(setq ielm-working-buffer (or (get-buffer buf) (error "No such buffer")))
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(ielm-print-working-buffer))
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;;; Other bindings
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(defun ielm-return nil
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"Newline and indent, or evaluate the sexp before the prompt.
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Complete sexps are evaluated; for incomplete sexps inserts a newline
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and indents. If however `ielm-dynamic-return' is nil, this always
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simply inserts a newline."
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(interactive)
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(if ielm-dynamic-return
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(let ((state
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(save-excursion
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(end-of-line)
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(parse-partial-sexp (ielm-pm)
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(point)))))
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(if (and (< (car state) 1) (not (nth 3 state)))
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(ielm-send-input)
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(if (and ielm-dynamic-multiline-inputs
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(save-excursion
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(beginning-of-line)
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(looking-at comint-prompt-regexp)))
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(save-excursion
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(goto-char (ielm-pm))
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(newline 1)))
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(newline-and-indent)))
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(newline)))
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(defun ielm-input-sender (proc input)
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;; Just sets the variable ielm-input, which is in the scope of
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;; `ielm-send-input's call.
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(setq ielm-input input))
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(defun ielm-send-input nil
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"Evaluate the Emacs Lisp expression after the prompt."
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(interactive)
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(let ((buf (current-buffer))
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ielm-input) ; set by ielm-input-sender
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(comint-send-input) ; update history, markers etc.
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(ielm-eval-input ielm-input)))
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;;; Utility functions
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(defun ielm-is-whitespace (string)
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"Return non-nil if STRING is all whitespace."
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(or (string= string "") (string-match "\\`[ \t\n]+\\'" string)))
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(defun ielm-format-errors (errlist)
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(let ((result ""))
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(while errlist
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(setq result (concat result (prin1-to-string (car errlist)) ", "))
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(setq errlist (cdr errlist)))
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(substring result 0 -2)))
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(defun ielm-format-error (err)
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;; Return a string form of the error ERR.
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(format "%s%s"
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(or (get (car err) 'error-message) "Peculiar error")
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(if (cdr err)
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(format ": %s" (ielm-format-errors (cdr err)))
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"")))
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;;; Evaluation
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(defun ielm-eval-input (ielm-string)
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"Evaluate the Lisp expression IELM-STRING, and pretty-print the result."
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;; This is the function that actually `sends' the input to the
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;; `inferior Lisp process'. All comint-send-input does is works out
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;; what that input is. What this function does is evaluates that
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;; input and produces `output' which gets inserted into the buffer,
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;; along with a new prompt. A better way of doing this might have
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;; been to actually send the output to the `cat' process, and write
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;; this as in output filter that converted sexps in the output
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;; stream to their evaluated value. But that would have involved
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;; more process coordination than I was happy to deal with.
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;;
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;; NOTE: all temporary variables in this function will be in scope
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;; during the eval, and so need to have non-clashing names.
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(let (ielm-form ; form to evaluate
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ielm-pos ; End posn of parse in string
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ielm-result ; Result, or error message
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ielm-error-type ; string, nil if no error
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(ielm-output "") ; result to display
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(ielm-wbuf ielm-working-buffer) ; current buffer after evaluation
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(ielm-pmark (ielm-pm)))
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(if (not (ielm-is-whitespace ielm-string))
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(progn
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(condition-case err
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(let (rout)
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(setq rout (read-from-string ielm-string))
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(setq ielm-form (car rout))
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(setq ielm-pos (cdr rout)))
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(error (setq ielm-result (ielm-format-error err))
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(setq ielm-error-type "Read error")))
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(if ielm-error-type nil
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;; Make sure working buffer has not been killed
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(if (not (buffer-name ielm-working-buffer))
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(setq ielm-result "Working buffer has been killed"
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ielm-error-type "IELM Error"
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ielm-wbuf (current-buffer))
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(if (ielm-is-whitespace (substring ielm-string ielm-pos))
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;; need this awful let convolution to work around
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;; an Emacs bug involving local vbls and let binding
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(let ((:save :)
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(::save ::)
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(:::save :::))
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(save-excursion
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(set-buffer ielm-working-buffer)
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(condition-case err
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(let ((: :save)
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(:: ::save)
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(::: :::save)
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(ielm-obuf (current-buffer)))
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(setq ielm-result (eval ielm-form))
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(setq ielm-wbuf (current-buffer))
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;; The eval may have changed current-buffer;
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;; need to set it back here to avoid a bug
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;; in let. Don't want to use save-excursion
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;; because we want to allow changes in point.
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(set-buffer ielm-obuf))
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(error (setq ielm-result (ielm-format-error err))
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(setq ielm-error-type "Eval error"))
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(quit (setq ielm-result "Quit during evaluation")
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(setq ielm-error-type "Eval error")))))
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(setq ielm-error-type "IELM error")
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(setq ielm-result "More than one sexp in input"))))
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;; If the eval changed the current buffer, mention it here
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(if (eq ielm-wbuf ielm-working-buffer) nil
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(message "current buffer is now: %s" ielm-wbuf)
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(setq ielm-working-buffer ielm-wbuf))
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(goto-char ielm-pmark)
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(if (not ielm-error-type)
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(condition-case err
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;; Self-referential objects cause loops in the printer, so
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;; trap quits here. May as well do errors, too
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(setq ielm-output (concat ielm-output (pp-to-string ielm-result)))
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(error (setq ielm-error-type "IELM Error")
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(setq ielm-result "Error during pretty-printing (bug in pp)"))
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(quit (setq ielm-error-type "IELM Error")
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(setq ielm-result "Quit during pretty-printing"))))
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(if ielm-error-type
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(progn
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(if ielm-noisy (ding))
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(setq ielm-output (concat ielm-output "*** " ielm-error-type " *** "))
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(setq ielm-output (concat ielm-output ielm-result)))
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;; There was no error, so shift the ::: values
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(setq ::: ::)
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(setq :: :)
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(setq : ielm-result))
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(setq ielm-output (concat ielm-output "\n"))))
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(setq ielm-output (concat ielm-output ielm-prompt))
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(comint-output-filter (ielm-process) ielm-output)))
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;;; Process and marker utilities
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(defun ielm-process nil
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;; Return the current buffer's process.
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(get-buffer-process (current-buffer)))
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(defun ielm-pm nil
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;; Return the process mark of the current buffer.
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(process-mark (get-buffer-process (current-buffer))))
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(defun ielm-set-pm (pos)
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;; Set the process mark in the current buffer to POS.
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(set-marker (process-mark (get-buffer-process (current-buffer))) pos))
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;;; Major mode
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(defun inferior-emacs-lisp-mode nil
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"Major mode for interactively evaluating Emacs Lisp expressions.
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Uses the interface provided by `comint-mode' (which see).
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* \\<ielm-map>\\[ielm-send-input] evaluates the sexp following the prompt. There must be at most
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one top-level sexp per prompt.
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* \\[ielm-return] inserts a newline and indents, or evaluates a
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complete expression (but see variable `ielm-dynamic-return').
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Inputs longer than one line are moved to the line following the
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prompt (but see variable `ielm-dynamic-multiline-inputs').
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* \\[comint-dynamic-complete] completes Lisp symbols (or filenames, within strings),
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or indents the line if there is nothing to complete.
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During evaluations, the values of the variables `:', `::', and `:::'
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are the results of the previous, second previous and third previous
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evaluations respectively.
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The current working buffer may be changed (with a call to
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`set-buffer', or with \\[ielm-change-working-buffer]), and its value
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is preserved between successive evaluations. In this way, expressions
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may be evaluated in a different buffer than the *ielm* buffer.
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Display the name of the working buffer with \\[ielm-print-working-buffer],
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or the buffer itself with \\[ielm-display-working-buffer].
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Expressions evaluated by IELM are not subject to `debug-on-quit' or
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`debug-on-error'.
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The behaviour of IELM may be customised with the following variables:
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* To stop beeping on error, set `ielm-noisy' to nil
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* If you don't like the prompt, you can change it by setting `ielm-prompt'.
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* Set `ielm-dynamic-return' to nil for bindings like `lisp-interaction-mode'
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* Entry to this mode runs `comint-mode-hook' and `ielm-mode-hook'
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(in that order).
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Customised bindings may be defined in `ielm-map', which currently contains:
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\\{ielm-map}"
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(interactive)
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(comint-mode)
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(setq comint-prompt-regexp (concat "^" (regexp-quote ielm-prompt)))
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(make-local-variable 'paragraph-start)
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(setq paragraph-start comint-prompt-regexp)
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(setq comint-input-sender 'ielm-input-sender)
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(setq comint-process-echoes nil)
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(setq comint-dynamic-complete-functions
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'(ielm-tab comint-replace-by-expanded-history ielm-complete-filename ielm-complete-symbol))
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(setq comint-get-old-input 'ielm-get-old-input)
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(setq major-mode 'inferior-emacs-lisp-mode)
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(setq mode-name "IELM")
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(use-local-map ielm-map)
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(set-syntax-table emacs-lisp-mode-syntax-table)
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(make-local-variable 'indent-line-function)
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(make-local-variable 'ielm-working-buffer)
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(setq ielm-working-buffer (current-buffer))
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(setq indent-line-function 'ielm-indent-line)
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;; Value holders
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(setq : nil)
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(make-local-variable ':)
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(setq :: nil)
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(make-local-variable '::)
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(setq ::: nil)
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(make-local-variable ':::)
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;; A dummy process to keep comint happy. It will never get any input
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(if (comint-check-proc (current-buffer)) nil
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(start-process "ielm" (current-buffer) "cat")
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(process-kill-without-query (ielm-process))
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(goto-char (point-max))
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;; Add a silly header
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(insert ielm-header)
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(ielm-set-pm (point-max))
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(comint-output-filter (ielm-process) ielm-prompt)
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(set-marker comint-last-input-start (ielm-pm))
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(set-process-filter (get-buffer-process (current-buffer)) 'comint-output-filter))
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(run-hooks 'ielm-mode-hook))
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(defun ielm-get-old-input nil
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;; Return the previous input surrounding point
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(save-excursion
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(beginning-of-line)
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(if (looking-at comint-prompt-regexp) nil
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(re-search-backward comint-prompt-regexp))
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(comint-skip-prompt)
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(buffer-substring (point) (progn (forward-sexp 1) (point)))))
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;;; User command
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;;;###autoload
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(defun ielm nil
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"Interactively evaluate Emacs Lisp expressions.
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Switches to the buffer *ielm*, or creates it if it does not exist."
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(interactive)
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(if (comint-check-proc "*ielm*") nil
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(progn
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(set-buffer (get-buffer-create "*ielm*"))
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(inferior-emacs-lisp-mode)))
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(switch-to-buffer "*ielm*"))
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;;; ielm.el ends here
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