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572 lines
21 KiB
EmacsLisp
572 lines
21 KiB
EmacsLisp
;;; ielm.el --- interaction mode for Emacs Lisp
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;; Copyright (C) 1994, 2001-2012 Free Software Foundation, Inc.
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;; Author: David Smith <maa036@lancaster.ac.uk>
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;; Maintainer: FSF
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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 3 of the License, or
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;; (at your option) 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. If not, see <http://www.gnu.org/licenses/>.
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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 start: M-x ielm. Type C-h m in the *ielm* buffer for more info.
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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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(defgroup ielm nil
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"Interaction mode for Emacs Lisp."
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:group 'lisp)
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(defcustom ielm-noisy t
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"If non-nil, IELM will beep on error."
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:type 'boolean
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:group 'ielm)
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(defcustom ielm-prompt-read-only t
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"If non-nil, the IELM prompt is read only.
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The read only region includes the newline before the prompt.
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Setting this variable does not affect existing IELM runs.
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This works by setting the buffer-local value of `comint-prompt-read-only'.
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Setting that value directly affects new prompts in the current buffer.
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If this option is enabled, then the safe way to temporarily
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override the read-only-ness of IELM prompts is to call
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`comint-kill-whole-line' or `comint-kill-region' with no
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narrowing in effect. This way you will be certain that none of
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the remaining prompts will be accidentally messed up. You may
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wish to put something like the following in your `.emacs' file:
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\(add-hook 'ielm-mode-hook
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(lambda ()
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(define-key ielm-map \"\\C-w\" 'comint-kill-region)
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(define-key ielm-map [C-S-backspace]
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'comint-kill-whole-line)))
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If you set `comint-prompt-read-only' to t, you might wish to use
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`comint-mode-hook' and `comint-mode-map' instead of
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`ielm-mode-hook' and `ielm-map'. That will affect all comint
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buffers, including IELM buffers. If you sometimes use IELM on
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text-only terminals or with `emacs -nw', you might wish to use
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another binding for `comint-kill-whole-line'."
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:type 'boolean
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:group 'ielm
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:version "22.1")
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(defcustom ielm-prompt "ELISP> "
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"Prompt used in IELM.
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Setting this variable does not affect existing IELM runs.
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Interrupting the IELM process with \\<ielm-map>\\[comint-interrupt-subjob],
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and then restarting it using \\[ielm], makes the then current
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default value affect _new_ prompts. Unless the new prompt
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differs only in text properties from the old one, IELM will no
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longer recognize the old prompts. However, executing \\[ielm]
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does not update the prompt of an *ielm* buffer with a running process.
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For IELM buffers that are not called `*ielm*', you can execute
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\\[inferior-emacs-lisp-mode] in that IELM buffer to update the value,
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for new prompts. This works even if the buffer has a running process."
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:type 'string
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:group 'ielm)
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(defvar ielm-prompt-internal "ELISP> "
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"Stored value of `ielm-prompt' in the current IELM buffer.
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This is an internal variable used by IELM. Its purpose is to
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prevent a running IELM process from being messed up when the user
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customizes `ielm-prompt'.")
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(defcustom ielm-dynamic-return t
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"Controls whether \\<ielm-map>\\[ielm-return] has intelligent behavior 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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:type 'boolean
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:group 'ielm)
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(defcustom 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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:type 'boolean
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:group 'ielm)
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(defcustom ielm-mode-hook nil
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"Hooks to be run when IELM (`inferior-emacs-lisp-mode') is started."
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:options '(turn-on-eldoc-mode)
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:type 'hook
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:group 'ielm)
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(defvaralias 'inferior-emacs-lisp-mode-hook 'ielm-mode-hook)
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(defvar * nil
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"Most recent value evaluated in IELM.")
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(defvar ** nil
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"Second-most-recent value evaluated in IELM.")
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(defvar *** nil
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"Third-most-recent value evaluated in IELM.")
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(defvar ielm-match-data nil
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"Match data saved at the end of last command.")
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(defvar *1 nil
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"During IELM evaluation, most recent value evaluated in IELM.
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Normally identical to `*'. However, if the working buffer is an IELM
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buffer, distinct from the process buffer, then `*' gives the value in
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the working buffer, `*1' the value in the process buffer.
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The intended value is only accessible during IELM evaluation.")
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(defvar *2 nil
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"During IELM evaluation, second-most-recent value evaluated in IELM.
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Normally identical to `**'. However, if the working buffer is an IELM
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buffer, distinct from the process buffer, then `**' gives the value in
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the working buffer, `*2' the value in the process buffer.
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The intended value is only accessible during IELM evaluation.")
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(defvar *3 nil
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"During IELM evaluation, third-most-recent value evaluated in IELM.
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Normally identical to `***'. However, if the working buffer is an IELM
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buffer, distinct from the process buffer, then `***' gives the value in
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the working buffer, `*3' the value in the process buffer.
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The intended value is only accessible during IELM evaluation.")
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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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"*** Welcome to IELM *** Type (describe-mode) for help.\n"
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"Message to display when IELM is started.")
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(defvar ielm-map
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(let ((map (make-sparse-keymap)))
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(define-key map "\t" 'comint-dynamic-complete)
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(define-key map "\C-m" 'ielm-return)
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(define-key map "\C-j" 'ielm-send-input)
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(define-key map "\e\C-x" 'eval-defun) ; for consistency with
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(define-key map "\e\t" 'completion-at-point) ; lisp-interaction-mode
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;; These bindings are from `lisp-mode-shared-map' -- can you inherit
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;; from more than one keymap??
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(define-key map "\e\C-q" 'indent-sexp)
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(define-key map "\177" 'backward-delete-char-untabify)
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;; Some convenience bindings for setting the working buffer
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(define-key map "\C-c\C-b" 'ielm-change-working-buffer)
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(define-key map "\C-c\C-f" 'ielm-display-working-buffer)
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(define-key map "\C-c\C-v" 'ielm-print-working-buffer)
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map)
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"Keymap for IELM mode.")
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(defvaralias 'inferior-emacs-lisp-mode-map 'ielm-map)
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(defvar ielm-font-lock-keywords
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'(("\\(^\\*\\*\\*[^*]+\\*\\*\\*\\)\\(.*$\\)"
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(1 font-lock-comment-face)
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(2 font-lock-constant-face)))
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"Additional expressions to highlight in IELM buffers.")
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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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(when (or (eq (preceding-char) ?\n)
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(eq (char-syntax (preceding-char)) ?\s))
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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 modified 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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(when (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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(when (save-excursion (comint-bol) (bolp))
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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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(let ((buffer (get-buffer buf)))
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(if (and buffer (buffer-live-p buffer))
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(setq ielm-working-buffer buffer)
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(error "No such buffer: %S" buf)))
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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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(when (and ielm-dynamic-multiline-inputs
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(save-excursion
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(beginning-of-line)
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(looking-at-p 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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(defvar ielm-input)
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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 (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-or-comment (string)
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"Return non-nil if STRING is all whitespace or a comment."
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(or (string= string "")
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(string-match-p "\\`[ \t\n]*\\(?:;.*\\)*\\'" string)))
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;;; Evaluation
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(defvar ielm-string)
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(defvar ielm-form)
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(defvar ielm-pos)
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(defvar ielm-result)
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(defvar ielm-error-type)
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(defvar ielm-output)
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(defvar ielm-wbuf)
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(defvar ielm-pmark)
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(defun ielm-eval-input (input-string)
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"Evaluate the Lisp expression INPUT-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-string input-string) ; input expression, as a string
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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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(unless (ielm-is-whitespace-or-comment ielm-string)
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(condition-case err
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(let ((rout (read-from-string ielm-string)))
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(setq ielm-form (car rout)
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ielm-pos (cdr rout)))
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(error (setq ielm-result (error-message-string err))
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(setq ielm-error-type "Read error")))
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(unless ielm-error-type
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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-or-comment (substring ielm-string ielm-pos))
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;; To correctly handle the ielm-local variables *,
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;; ** and ***, we need a temporary buffer to be
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;; current at entry to the inner of the next two let
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;; forms. We need another temporary buffer to exit
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;; that same let. To avoid problems, neither of
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;; these buffers should be alive during the
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;; evaluation of ielm-form.
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(let ((*1 *)
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(*2 **)
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(*3 ***)
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ielm-temp-buffer)
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(set-match-data ielm-match-data)
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(save-excursion
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(with-temp-buffer
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(condition-case err
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(unwind-protect
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;; The next let form creates default
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;; bindings for *, ** and ***. But
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;; these default bindings are
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;; identical to the ielm-local
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;; bindings. Hence, during the
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;; evaluation of ielm-form, the
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;; ielm-local values are going to be
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;; used in all buffers except for
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;; other ielm buffers, which override
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;; them. Normally, the variables *1,
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;; *2 and *3 also have default
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;; bindings, which are not overridden.
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(let ((* *1)
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(** *2)
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(*** *3))
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(kill-buffer (current-buffer))
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(set-buffer ielm-wbuf)
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(setq ielm-result
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(eval ielm-form lexical-binding))
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(setq ielm-wbuf (current-buffer))
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(setq
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ielm-temp-buffer
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(generate-new-buffer " *ielm-temp*"))
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(set-buffer ielm-temp-buffer))
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(when ielm-temp-buffer
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(kill-buffer ielm-temp-buffer)))
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(error (setq ielm-result (error-message-string 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-match-data (match-data)))
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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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(unless (eq ielm-wbuf ielm-working-buffer)
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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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(unless ielm-error-type
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(condition-case nil
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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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(when 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-internal))
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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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(define-derived-mode inferior-emacs-lisp-mode comint-mode "IELM"
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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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The current working buffer may be changed (with a call to `set-buffer',
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or with \\[ielm-change-working-buffer]), and its value is preserved between successive
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|
evaluations. In this way, expressions may be evaluated in a different
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|
buffer than the *ielm* buffer. By default, its name is shown on the
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mode line; you can always display it with \\[ielm-print-working-buffer], or the buffer itself
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|
with \\[ielm-display-working-buffer].
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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. If the working buffer is another IELM
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|
buffer, then the values in the working buffer are used. The variables
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`*1', `*2' and `*3', yield the process buffer values.
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|
|
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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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|
|
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The behavior of IELM may be customized 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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* If you do not like that the prompt is (by default) read-only, set
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|
`ielm-prompt-read-only' to nil.
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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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|
|
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Customized bindings may be defined in `ielm-map', which currently contains:
|
|
\\{ielm-map}"
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|
:syntax-table emacs-lisp-mode-syntax-table
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|
|
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(setq comint-prompt-regexp (concat "^" (regexp-quote ielm-prompt)))
|
|
(set (make-local-variable 'paragraph-separate) "\\'")
|
|
(set (make-local-variable 'paragraph-start) comint-prompt-regexp)
|
|
(setq comint-input-sender 'ielm-input-sender)
|
|
(setq comint-process-echoes nil)
|
|
(set (make-local-variable 'comint-dynamic-complete-functions)
|
|
'(ielm-tab comint-replace-by-expanded-history
|
|
ielm-complete-filename ielm-complete-symbol))
|
|
(set (make-local-variable 'ielm-prompt-internal) ielm-prompt)
|
|
(set (make-local-variable 'comint-prompt-read-only) ielm-prompt-read-only)
|
|
(setq comint-get-old-input 'ielm-get-old-input)
|
|
(set (make-local-variable 'comint-completion-addsuffix) '("/" . ""))
|
|
(setq mode-line-process '(":%s on " (:eval (buffer-name ielm-working-buffer))))
|
|
|
|
(set (make-local-variable 'indent-line-function) 'ielm-indent-line)
|
|
(set (make-local-variable 'ielm-working-buffer) (current-buffer))
|
|
(set (make-local-variable 'fill-paragraph-function) 'lisp-fill-paragraph)
|
|
(add-hook 'completion-at-point-functions
|
|
'lisp-completion-at-point nil 'local)
|
|
|
|
;; Value holders
|
|
(set (make-local-variable '*) nil)
|
|
(set (make-local-variable '**) nil)
|
|
(set (make-local-variable '***) nil)
|
|
(set (make-local-variable 'ielm-match-data) nil)
|
|
|
|
;; font-lock support
|
|
(set (make-local-variable 'font-lock-defaults)
|
|
'(ielm-font-lock-keywords nil nil ((?: . "w") (?- . "w") (?* . "w"))))
|
|
|
|
;; A dummy process to keep comint happy. It will never get any input
|
|
(unless (comint-check-proc (current-buffer))
|
|
;; Was cat, but on non-Unix platforms that might not exist, so
|
|
;; use hexl instead, which is part of the Emacs distribution.
|
|
(condition-case nil
|
|
(start-process "ielm" (current-buffer) "hexl")
|
|
(file-error (start-process "ielm" (current-buffer) "cat")))
|
|
(set-process-query-on-exit-flag (ielm-process) nil)
|
|
(goto-char (point-max))
|
|
|
|
;; Lisp output can include raw characters that confuse comint's
|
|
;; carriage control code.
|
|
(set (make-local-variable 'comint-inhibit-carriage-motion) t)
|
|
|
|
;; Add a silly header
|
|
(insert ielm-header)
|
|
(ielm-set-pm (point-max))
|
|
(unless comint-use-prompt-regexp
|
|
(let ((inhibit-read-only t))
|
|
(add-text-properties
|
|
(point-min) (point-max)
|
|
'(rear-nonsticky t field output inhibit-line-move-field-capture t))))
|
|
(comint-output-filter (ielm-process) ielm-prompt-internal)
|
|
(set-marker comint-last-input-start (ielm-pm))
|
|
(set-process-filter (get-buffer-process (current-buffer)) 'comint-output-filter)))
|
|
|
|
(defun ielm-get-old-input nil
|
|
;; Return the previous input surrounding point
|
|
(save-excursion
|
|
(beginning-of-line)
|
|
(unless (looking-at-p comint-prompt-regexp)
|
|
(re-search-backward comint-prompt-regexp))
|
|
(comint-skip-prompt)
|
|
(buffer-substring (point) (progn (forward-sexp 1) (point)))))
|
|
|
|
;;; User command
|
|
|
|
;;;###autoload
|
|
(defun ielm nil
|
|
"Interactively evaluate Emacs Lisp expressions.
|
|
Switches to the buffer `*ielm*', or creates it if it does not exist."
|
|
(interactive)
|
|
(let (old-point)
|
|
(unless (comint-check-proc "*ielm*")
|
|
(with-current-buffer (get-buffer-create "*ielm*")
|
|
(unless (zerop (buffer-size)) (setq old-point (point)))
|
|
(inferior-emacs-lisp-mode)))
|
|
(switch-to-buffer "*ielm*")
|
|
(when old-point (push-mark old-point))))
|
|
|
|
(provide 'ielm)
|
|
|
|
;;; ielm.el ends here
|