Update README, to detail the Makefile

I’d hoped these tweaks to the system-file would
help binary-making work with ECL, but no dice.
Anyway, the Makefile has a basic build recipe and
one for installing Quicklisp, should the user not
already have it installed.

Makefile

@@ -0,0 +1,20 @@
+LISP ?= sbcl
+
+all: clean build
+
+clean:
+	-rm eksd
+
+quicklisp:
+	curl "https://beta.quicklisp.org/quicklisp.lisp" -o /tmp/ql.lisp
+	$(LISP) --load /tmp/ql.lisp \
+	--eval '(quicklisp-quickstart:install :path "~/.local/lib/quicklisp/")' \
+	--eval '(ql:add-to-init-file)' \
+	--eval '(quit)'
+
+build:
+	$(LISP) --load eksd.asd \
+	--eval '(ql:quickload :eksd)' \
+	--eval '(ql:quickload :eksd.unix)' \
+	--eval '(asdf:make :eksd.unix)' \
+	--eval '(quit)'

README.md

@@ -1,9 +1,9 @@
 # EKSD
 
-xxd is a very good hexdump program that makes editing files on UNIX very easy.
+[xxd](https://hg.256bit.org/vim/file/tip/src/xxd) is a very good hexdump program that makes editing files on UNIX very easy.
 It also doesn't support text-tables. Which sucks.
 
-eksd is a clone of a good hexdump program (even matching several arguments
+[eksd](https://hak.xwx.moe/jadedctrl/eksd) is a clone of a good hexdump program (even matching several arguments
 exactly)… except it supports text-tables.
 
 ## Usage
@@ -23,7 +23,7 @@ $ eksd -t $TABLE_FILE $FILE > $HEXDUMP_FILE
 ```
 
 Text-tables are in a simple format— one hexcode per line, followed by its
-character. See ./text-tables/* for examples.
+character. See [./text_tables/*](text_tables/) for examples.
 
 By default, eksd uses a built-in *fancy* text-table— it's basic ASCII,
 except it'll print nice pictographics for newline characters, etc. These
@@ -42,7 +42,7 @@ $ eksd -t castle-table.txt castlevania.nes  | grep -A4 "18e80"
 00018eb0: 5454 5454 5454 6668 6086 6e54 5454 5454  ......DEATH.....
 00018ec0: 5454 5462 6876 7c54 7688 6c7c 8470 5454  ...BELO.LUGOSI..
 ```
-And here's that same file in xxd (just because I feel like showing off):
+And here's that same file in [Vim’s](https://www.vim.org) xxd (just because I feel like showing off):
 ```
 $ xxd castlevania.nes | grep -A4 "18e80"
 00018e80: 5454 5454 866e 6854 6460 8486 5454 5454  TTTT.nhTd`..TTTT
@@ -54,20 +54,22 @@ $ xxd castlevania.nes | grep -A4 "18e80"
 
 
 ## Installation
-Making a binary requires a Lisp (I recommend SBCL) and Quicklisp
+Making a binary requires [an implementation](https://common-lisp.net/implementations) of Common Lisp installed: [Steel Bank Common Lisp](https://sbcl.org/) is our implementation-of-choice. It’s available on most operating systems under the package name `sbcl`.
-(https://quicklisp.org).
+
+You also need the library-manager [Quicklisp](https://quicklisp.org), which can [be installed](https://www.quicklisp.org/beta/#installation) quite easily, including via our [Makefile](Makefile).
+
+To install quicklisp, build a binary, and install it, simply:
 
-Put this repository into your `quicklisp/local-projects/`, then run, in your
-lisp interpreter:
 ```
-# (ql:quickload '(eksd eksd-unix))
+$ make quicklisp
-# (save-lisp-and-die "eksd" :toplevel #'eksd-unix:invoke :executable t)
+$ make build
+$ sudo cp eksd /usr/local/bin/eksd
 ```
 
-And bam, you've made a binary. Cool.
+Bam, you've made and installed a binary! Cool!
 
 
 ## Misc
 * License is the GNU GPLv3 (COPYING.txt)
-* Author is Jaidyn Ann <jadedctrl@teknik.io>
+* Author is Jaidyn Ann <jadedctrl@posteo.at>
-* Sauce is at https://github.com/jadedctrl/eksd
+* Sauce is at https://hak.xwx.moe/jadedctrl/eksd

eksd.asd

@@ -1,15 +1,23 @@
-(defsystem "eksd"
+(require "asdf")
-	   :version "0.1"
-           :license "GPLv3"
-	   :author "Jaidyn Ann <jadedctrl@teknik.io>"
-	   :description "For reading files into hex— `xxd`-like with text-tables."
-	   :depends-on ()
-	   :components ((:file "eksd")))
 
-(defsystem "eksd-unix"
+(asdf:defsystem "eksd"
-	   :version "0.1"
+  :version "0.11"
-           :license "GPLv3"
+  :license "GPLv3"
-	   :author "Jaidyn Ann <jadedctrl@teknik.io>"
+  :author "Jaidyn Ann <jadedctrl@posteo.at>"
-	   :description "UNIX terminal front-tend to eksd. `xxd` twin."
+  :homepage "https://hak.xwx.moe/jadedctrl/eksd"
-	   :depends-on (:eksd :unix-opts :cl-strings)
+  :description "For reading files into hex— `xxd`-like with text-tables."
-	   :components ((:file "eksd-unix")))
+  :depends-on ()
+  :components ((:file "src/eksd")))
+
+(asdf:defsystem "eksd.unix"
+  :version "0.11"
+  :license "GPLv3"
+  :author "Jaidyn Ann <jadedctrl@posteo.at>"
+  :homepage "https://hak.xwx.moe/jadedctrl/eksd"
+  :description "UNIX terminal front-tend to eksd. `xxd` twin."
+  :class asdf:program-system
+  :build-operation "program-op"
+  :build-pathname "eksd"
+  :entry-point "eksd.unix:main"
+  :depends-on (:cl-strings :eksd :unix-opts)
+  :components ((:file "src/unix")))

src/eksd.lisp

@@ -1,11 +1,19 @@
-;; This file is free software: you can redistribute it and/or modify
+;;;; eksd: Backend to the xxd-clone hex-dump program eksd.
-;; it under the terms of version 3 of the GNU General Public License
+
-;; as published by the Free Software Foundation.
+;; Copyright © 2019–2024 Jaidyn Ann <jadedctrl@posteo.at>
+;;
+;; This program is free software: you can redistribute it and/or
+;; modify it under the terms of the GNU General Public License as
+;; published by the Free Software Foundation, either version 3 of
+;; the License, or (at your option) any later version.
 ;;
 ;; This program is distributed in the hope that it will be useful,
 ;; but WITHOUT ANY WARRANTY; without even the implied warranty of
-;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
 ;; GNU General Public License for more details.
+;;
+;; You should have received a copy of the GNU General Public License
+;; along with this program. If not, see <https://www.gnu.org/licenses/>.
 
 (defpackage :eksd
   (:use :cl)
@@ -22,8 +30,9 @@
 
 (in-package :eksd)
 
-;; —————————————————————————————————————
+
-
+;;; Constants
+;;; —————————————————————————————————————
 (defparameter *ascii-text-table*
   '(("20" #\space)("21" #\!)("22" #\")("23" #\#)("24" #\$) ("25" #\%)
     ("26" #\&) ("27" #\') ("28" #\() ("29" #\)) ("2A" #\*) ("2B" #\+)
@@ -47,16 +56,16 @@
 (defparameter *fancy-text-table* (append *ascii-text-table* *fancy-text-bits*))
 
 
-;; —————————————————————————————————————
+
-;; X → HEX
+;;; X → Hex
-
+;;; —————————————————————————————————————
-;; STREAM → LIST_OF_STRINGS
+;; stream → list-of-strings
 (defun stream-to-hex (stream)
   "Return a stream's data as a list of hexadecimal strings."
   (loop :while   (listen stream)
         :collect (read-hex stream)))
 
-;; PATHNAME → LIST_OF_STRINGS
+;; pathname → list-of-strings
 (defun file-to-hex (pathname)
   "Return a list of  a file's octets represented in hexadecimal strings."
   (with-open-file (fstream pathname
@@ -64,17 +73,16 @@
     (stream-to-hex fstream)))
 
 
-
+
-;; —————————————————————————————————————
+;;; Hex → X
-;; HEX → X
+;;; —————————————————————————————————————
-
+;; list-of-strings stream → nil
-;; LIST_OF_STRINGS STREAM → NIL
 (defun hex-to-stream (hexes stream)
   "Write a list of bytes (in hex-string format) to a stream."
   (loop :for hex :in hexes
         :do (write-hex hex stream)))
 
-;; LIST_OF_STRINGS PATHNAME → NIL
+;; list-of-strings pathname → nil
 (defun hex-to-file (hexes pathname)
   "Write a list of bytes (in hex-string format) to a file."
   (with-open-file (fstream pathname
@@ -82,62 +90,60 @@
     (hex-to-stream hexes fstream)))
 
 
-
+
+;; Text-table fun
 ;; —————————————————————————————————————
-;; TEXT-TABLE FUN
-
 (defgeneric hex-to-char (hex/es &optional text-table) 
   (:documentation "Return a hexadecimal's respective character (as string)
                   according to the given text-table."))
 
-;; STRING LIST → STRING
+;; string list → string
 (defmethod hex-to-char ((hex string) &optional (text-table *ascii-text-table*))
   (or (cadr (assoc hex text-table :test #'equal)) #\.))
 
-;; LIST_OF_STRINGS LIST → LIST_OF_STRINGS
+;; list-of-strings list → list-of-strings
 (defmethod hex-to-char ((hexes list) &optional (text-table *ascii-text-table*))
   (mapcar (lambda (hex) (hex-to-char hex text-table)) hexes))
 
 
-;; PATHNAME LIST → LIST_OF_STRINGS
+;; pathname list → list_of_strings
 (defun file-to-char (pathname &optional (text-table *ascii-text-table*))
   "Print character representation of a file, as per the given character table."
   (hex-to-char (file-to-hex pathname) text-table))
 
-
+;; character list → string
-;; CHARACTER LIST → STRING
 (defun char-hex (char &optional text-table)
   "Return a character's hex, given a text-table."
   (if (not text-table) 
     (integer-to-hex (char-code char))
     (cadr (assoc char (mapcar #'reverse text-table)))))
 
+;; string list → list
 (defun string-hex (string &optional text-table)
+  "Given a string and text-table, return a list of its characters’ hex-codes."
   (loop :for char :across string
         :collect (char-hex char text-table)))
 
 
-
+
-;; —————————————————————————————————————
+;;; Misc
-;; MISC
+;;; —————————————————————————————————————
-
+;; stream → string
-;; STREAM → STRING
 (defun read-hex (stream)
   "Read a byte from a stream as a hexcode."
   (integer-to-hex (read-byte stream)))
 
-;; STREAM → STRING
+;; stream → string
 (defun write-hex (hex stream)
   "Read a byte from a stream as a hexcode."
   (write-byte (hex-to-integer hex) stream))
 
-
+;; number → string
-;; NUMBER → STRING
 (defun integer-to-hex (number)
   "Return the base-16 of a number."
   (format nil "~2,'0x" number))
 
-;; STRING → NUMBER
+;; string → number
 (defun hex-to-integer (hex)
   "Convert hex to a base-10 integer."
   (parse-integer hex :radix 16))

src/unix.lisp

@@ -1,75 +1,83 @@
-;; This file is free software: you can redistribute it and/or modify
+;;;; eksd.unix: UNIX-style cli interface for the xxd-clone eksd.
-;; it under the terms of version 3 of the GNU General Public License
+
-;; as published by the Free Software Foundation.
+;; Copyright © 2019–2024 Jaidyn Ann <jadedctrl@posteo.at>
+;;
+;; This program is free software: you can redistribute it and/or
+;; modify it under the terms of the GNU General Public License as
+;; published by the Free Software Foundation, either version 3 of
+;; the License, or (at your option) any later version.
 ;;
 ;; This program is distributed in the hope that it will be useful,
 ;; but WITHOUT ANY WARRANTY; without even the implied warranty of
-;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
 ;; GNU General Public License for more details.
+;;
+;; You should have received a copy of the GNU General Public License
+;; along with this program. If not, see <https://www.gnu.org/licenses/>.
 
-(defpackage :eksd-unix
+(defpackage :eksd.unix
   (:use :cl :eksd)
-  (:export :invoke
+  (:export :main
            *text-table*))
 
-(in-package :eksd-unix)
+(in-package :eksd.unix)
-
-;; —————————————————————————————————————
 
+
+;;; —————————————————————————————————————
 (opts:define-opts
-  (:name :help
+    (:name :help
-         :description "print this help text."
+       :description "print this help text."
-         :short #\h  :long "help")
+       :short #\h  :long "help")
-  (:name :reverse
+    (:name :reverse
-         :description "reverse operation: convert hexdump into binary."
+       :description "reverse operation: convert hexdump into binary."
-         :short #\r  :long "reverse")
+       :short #\r  :long "reverse")
   (:name :upcase
-         :description "print hexadecimal in uppercase."
+   :description "print hexadecimal in uppercase."
-         :short #\u  :long "upcase")
+   :short #\u  :long "upcase")
   (:name :width
-         :description "octets per line; 16 as default."
+   :description "octets per line; 16 as default."
-         :short #\c  :long "cols"
+   :short #\c  :long "cols"
-         :arg-parser #'parse-integer
+   :arg-parser #'parse-integer
-         :meta-var "COLS")
+   :meta-var "COLS")
   (:name :seek
-         :description "skip given amount of bytes in file."
+   :description "skip given amount of bytes in file."
-         :short #\s  :long "seek"
+   :short #\s  :long "seek"
-         :arg-parser #'parse-integer
+   :arg-parser #'parse-integer
-         :meta-var "OFFSET")
+   :meta-var "OFFSET")
   (:name :group
-         :description "octets per group; 2 as default."
+   :description "octets per group; 2 as default."
-         :short #\g  :long "groupsize"
+   :short #\g  :long "groupsize"
-         :arg-parser #'parse-integer
+   :arg-parser #'parse-integer
-         :meta-var "OCTETS")
+   :meta-var "OCTETS")
   (:name :ascii
-         :description "use simple-ascii for previews; default is fun."
+   :description "use simple-ascii for previews; default is fun."
-         :short #\a  :long "ascii")
+   :short #\a  :long "ascii")
   (:name :text-table
-         :description "specify a text-table; semi-ascii as default."
+   :description "specify a text-table; semi-ascii as default."
-         :short #\t  :long "table"
+   :short #\t  :long "table"
-         :arg-parser #'probe-file
+   :arg-parser #'probe-file
-         :meta-var "TABLE"))
+   :meta-var "TABLE"))
 
 
-;; —————————————————————————————————————
+
-;; MACROS
+;;; Macros
-
+;;; —————————————————————————————————————
-;; LIST SYMBOL FORM
+;; list symbol form
 (defmacro when-opt (opts option body)
   `(when (getf ,opts ,option)
      ,body))
 
-;; LIST SYMBOL FORM FORM
+;; list symbol form form
 (defmacro if-opt (opts option if-form &optional else-form)
   `(if (getf ,opts ,option)
-     ,if-form ,else-form))
+       ,if-form ,else-form))
 
 
-;; —————————————————————————————————————
+
-;; MAIN - INVOCATION
+;;; Main - Invocation
-
+;;; —————————————————————————————————————
-;; NIL → NIL
+;; nil → nil
-(defun invoke ()
+(defun main ()
   "Actual invocation of the program. This is what you should set as :toplevel."
   (multiple-value-bind (opts free) (opts:get-opts)
     (when-opt opts :help (help))
@@ -85,54 +93,51 @@
 
       (close input-stream))))
 
-
+;; number stream → nil
-;; NUMBER STREAM → NIL
 (defun help (&optional (exit-code 0) (stream *standard-output*))
   "Prints help message and dies."
   (unix-opts:describe :prefix "usage: eksd [-hr] [-t table-file] file"
                       :stream stream)
   (unix-opts:exit exit-code))
 
-;; —————————————————
+; list stream → nil
-
-;; LIST STREAM → NIL
 (defun reverse-or-dump (opts input-stream)
   "Determine if a hexdump or reversal's necessary— and execute it."
   (if-opt opts :reverse
-    (reverse-stream input-stream)
+          (reverse-stream input-stream)
-    (apply #'print-stream (choose-pstream-args opts input-stream))))
+          (apply #'print-stream (choose-pstream-args opts input-stream))))
 
 
-;; —————————————————————————————————————
+
-;; INPUT
+;;; Input
-
+;;; —————————————————————————————————————
-;; LIST → STREAM
+;; list → stream
 (defun choose-input-stream (free-args opts)
   "Select an input stream, between a file passed in free-args or stdin."
   (let* ((input-file   (car free-args))
          (input-file-p (ignore-errors (probe-file input-file)))
          (stdin-p      (listen *standard-input*)))
-    (cond ((and (getf opts :reverse) input-file-p)
+    (cond ((and (getf opts :reverse) input-file-p
-               (open input-file :direction :input :element-type 'character))
+                (open input-file :direction :input :element-type 'character)))
           (input-file-p (open-byte input-file))
           (stdin-p      *standard-input*))))
 
-;; LIST → NIL
+;; list → nil
 (defun choose-text-table (opts)
   "Choose the appropriate text-table— user-given or otherwise."
   (if-opt opts :text-table
           (setq *text-table* (parse-table-file (getf opts :text-table)))
           (if-opt opts :ascii
-            (setq *text-table* eksd:*ascii-text-table*)
+                  (setq *text-table* eksd:*ascii-text-table*)
-            (setq *text-table* eksd:*fancy-text-table*))))
+                  (setq *text-table* eksd:*fancy-text-table*))))
 
-;; LIST STREAM → NIL
+;; list stream → nil
 (defun choose-stream-position (opts stream)
   "Choose the correct stream position— if seek arg used, etc."
   (when (not (eq stream *standard-input*))
     (if-opt opts :seek (file-position stream (getf opts :seek)))))
 
-;; LIST STREAM → LIST
+;; list stream → list
 (defun choose-pstream-args (opts input-stream)
   "Take all options, and return the appropriate arguments to #'print-stream."
   (let ((args (list input-stream)))
@@ -141,33 +146,33 @@
     (when-opt opts :group  (nconc args `(:group ,(getf opts :group))))
     args))
 
-;; —————————————————
+
+;;; —————————————————
 
-;; STREAM NUMBER NUMBER → LIST NUMBER
+;; stream number number → list number
 (defun get-line-hex (stream index width)
   "Return a line's worth of octets; and a new octet-index."
   (values
-    (loop :while (listen stream) :for i :from 1 :to width
+   (loop :while (listen stream) :for i :from 1 :to width
-          :collect (eksd:read-hex stream) :do (incf index))
+         :collect (eksd:read-hex stream) :do (incf index))
-    index))
+   index))
 
 
+
+;; Output
 ;; —————————————————————————————————————
-;; OUTPUT
+;; stream number number stream
-
-;; STREAM NUMBER NUMBER STREAM
 (defun print-stream (stream &key (width 16) (group 2) (upcase nil) (out 't))
   "Print an entire stream in hex, xxd-style."
   (let ((index 0))
     (loop :while (listen stream)
           :do (setq index (print-line stream :out out :index index 
-                                      :group group :width width
+                                             :group group :width width
-                                      :upcase upcase)))))
+                                             :upcase upcase)))))
 
-
+;; stream stream number number number → number
-;; STREAM STREAM NUMBER NUMBER NUMBER → NUMBER
 (defun print-line (stream &key (out 't) (index 0) (width 16) (group 2)
-                               (upcase nil))
+                            (upcase nil))
   "Print a given line of xxd-style output— index, bytes, preview and all.
   Returns the new index of the stream."
   (multiple-value-bind (hexes new-index) (get-line-hex stream index width)
@@ -177,29 +182,29 @@
     (format t "~%")
     new-index))
 
-;; NUMBER STREAM → NIL
+;; number stream → nil
 (defun print-index (index &optional (out 't))
   "Print the current index, padded to 8 char-length and in hexadecimal."
   (format out "~8,,,'0@A: " (string-downcase (eksd:integer-to-hex index))))
 
-;; LIST_OF_STRINGS NUMBER STREAM → NIL
+;; list-of-strings number stream → nil
 (defun print-bytes (hexes group-size upcase &optional (out 't))
   "Print the given list of bytes on a line in specified-sized groupings."
   (mapcar (lambda (group)
             (format out (if upcase "~{~@:(~a~)~} " "~{~(~a~)~} ") group))
           (pairs hexes group-size)))
 
-;; LIST_OF_STRINGS STREAM → NIL
+;; list-of-strings stream → nil
 (defun print-preview (hexes &optional (out 't))
   "Print a given list of bytes' preview, as per ASCII table."
   (format out " ~{~A~}"
           (mapcar (lambda (hex) (hex-to-char hex *text-table*)) hexes)))
 
 
-;; —————————————————————————————————————
+
-;; REVERSAL
+;;; Reversal
-
+;;; —————————————————————————————————————
-;; STREAM STREAM → NIL
+;; stream stream → nil
 (defun reverse-stream (stream &optional (out *standard-output*))
   "Take a stream of xxd-style/eksd-output hexcode and convert back into binary."
   (loop :while (listen stream)
@@ -207,26 +212,26 @@
                       (write-byte (eksd:hex-to-integer byte) out))
                     (line-to-hexes (read-line stream)))))
 
-;; STRING → LIST
+;; string → list
 (defun line-to-hexes (line)
   "Convert an xxd-style/eksd-output hexcode line into a list of hexcodes."
   (mapcar (lambda (pair) (format nil "~{~A~}" pair))
-    (string-pairs
+          (string-pairs
-      (remove #\space (car (cl-strings:split
+                 (remove #\space (car (cl-strings:split
-                             (left-clip-string line ": ")"  "))))))
+                                            (left-clip-string line ": ")"  "))))))
 
 
-;; —————————————————————————————————————
+
-;; TEXT-TABLES
+;;; Text-tables
-
+;;; —————————————————————————————————————
-;; STRING → LIST
+;; string → list
 (defun parse-table-line (string)
   "Parse a text-table line into a pair of hex-code and preview character."
   (let ((chars (char-list string)))
     (list (format nil "~{~a~}" (list (car chars) (cadr chars)))
           (tail chars))))
 
-;; PATHNAME → LIST
+;; pathname → list
 (defun parse-table-file (pathname)
   "Parse a text-table file (hexcode followed by preview character) into a list
   of lists '(hexcode character)."
@@ -235,17 +240,17 @@
           :collect (parse-table-line (read-line istream)))))
 
 
-;; —————————————————————————————————————
+
-;; MISC
+;;; Misc
-
+;;; —————————————————————————————————————
-;; LIST NUMBER VARYING → LIST
+;; list number varying → list
 (defun list-pad (list target-length &optional (padding nil))
   "Pad a list out to length, by appending padding as necessary."
   (if (not (eq target-length (length list)))
-    (list-pad (append list (list padding)) target-length padding)
+      (list-pad (append list (list padding)) target-length padding)
-    list))
+      list))
 
-;; LIST NUMBER → LIST
+;; list number → list
 (defun pairs (list width &optional pairs)
   "Split a list into pairs (sublist) of a given width."
   (cond ((not list) pairs)
@@ -253,26 +258,31 @@
          (pairs (cdr list) width (nconc pairs `((,(car list))))))
         ((not (eq width (length (tail pairs))))
          (pairs (cdr list) width
-           (nconc (de-tail pairs) `(,(nconc (tail pairs) `(,(car list)))))))))
+                (nconc (de-tail pairs) `(,(nconc (tail pairs) `(,(car list)))))))))
 
-;; STRING CHARACTER → STRING
+;; string character → string
 (defun left-clip-string (string &optional (seperator #\space))
   "Clip a string up to the first instance of the seperator."
   (reduce (lambda (a b) (format nil "~A~A~A" a seperator b))
           (cdr (cl-strings:split string seperator))))
 
-;; STRING NUMBER → LIST
+;; string number → list
 (defun string-pairs (string &optional (pair-length 2))
   "Return a list of characters from a string in pairs of given length."
   (pairs (char-list string) pair-length))
 
-;; PATHNAME → STREAM
+;; pathname → stream
 (defun open-byte (pathname)
   "Open an input file as a byte-stream."
   (open pathname :direction :input :element-type '(unsigned-byte 8)))
 
-;; —————————————————
+;; string → list
+(defun char-list (string)
+  "Convert a string into a list of characters."
+  (loop :for char :across string :collect char))
+
+;; list → list
+(defun de-tail (list)
+  "Remove the last element from a list."
+  (reverse (cdr (reverse list))))
 
-(defun char-list (string) (loop :for char :across string :collect char))
-(defun de-tail (list) (reverse (cdr (reverse list))))
-(defun tail  (list) (car (last list)))