lisp/clhs.lisp @ 2316eb128101

;; Based on https://gist.github.com/fukamachi/3510ea1609c1b52830c2

(eval-when (:compile-toplevel :load-toplevel :execute)
  (ql:quickload '(:adopt :drakma :plump :clss :alexandria)
                :silent t))

(defpackage :clhs
  (:use :cl)
  (:export :toplevel :*ui*))

(in-package :clhs)


;;;; Config -------------------------------------------------------------------
(defparameter *default-hyperspec-url* "http://www.lispworks.com/documentation/HyperSpec/")
;; (defparameter *default-hyperspec-url* "file:///home/sjl/Dropbox/HyperSpec/HyperSpec/")
(defparameter *default-open-command* "open")
(defparameter *open* *default-open-command*)
(defparameter *url* *default-hyperspec-url*)


;;;; Curl ---------------------------------------------------------------------
(defun retrieve-url (url)
  (tagbody
    retry
    (multiple-value-bind (body status) (drakma:http-request url)
      (unless (= status 200)
        (restart-case
            (error "Failed to retrieve ~S (Code=~A)" url status)
          (retry-request ()
                         :report "Retry the request to URL."
                         (go retry))))
      (return-from retrieve-url body))))

(defun retrieve-file (path)
  (alexandria:read-file-into-string path))


(defun url (target)
  (format nil "~A~A" *url* target))

(defun retrieve (target)
  (let ((path-or-url (url target)))
    (if (string= "file://" path-or-url :end2 7)
      (retrieve-file (subseq path-or-url 7))
      (retrieve-url path-or-url))))


;;;; Cache --------------------------------------------------------------------
(defun cache-directory ()
  (let ((cache-dir
          (uiop:ensure-directory-pathname
            (uiop:getenv "XDG_CACHE_HOME")
            (merge-pathnames ".cache/" (user-homedir-pathname)))))
    (merge-pathnames #P"clhs/" cache-dir)))

(defun cache-file ()
  (merge-pathnames #P"symbols-map.sexp" (cache-directory)))

(defun retrieve-symbol-map ()
  (let ((body (retrieve "Front/X_AllSym.htm")))
    (map 'list
         (lambda (a)
           (cons (plump:text a)
                 (let ((path (plump:attribute a "href")))
                   ;; Omit "../" and URL fragment
                   (subseq path 3 (position #\# path)))))
         (clss:select "a[rel=definition]" (plump:parse body)))))

(defun rebuild-cache ()
  (let ((cache (cache-file)))
    (format t "Rebuilding cache at ~A~%" cache)
    (let ((symbols (retrieve-symbol-map)))
      (ensure-directories-exist cache)
      (with-open-file (out cache
                           :direction :output
                           :if-exists :supersede
                           :if-does-not-exist :create)
        (prin1 symbols out))
      symbols)))

(defun symbol-map ()
  (let ((cache (cache-file)))
    (if (probe-file cache)
      (uiop:read-file-form cache)
      (rebuild-cache))))

(defun find-symbol-path (target-symbol)
  (cdr (assoc target-symbol (symbol-map) :test #'string-equal)))

(defun run (target-symbol)
  (let ((path (find-symbol-path target-symbol)))
    (if path
      (let ((url (url path)))
        (format t "Opening ~A~%" url)
        (uiop:run-program `(,*open* ,url)
                          :ignore-error-status t
                          :input :interactive
                          :output :interactive)
        t)
      nil)))


;;;; User Interface -----------------------------------------------------------
(defmacro define-string (var string)
  `(defparameter ,var (format nil ,string)))

(define-string *documentation*
  "Look up SYMBOL in the Common Lisp HyperSpec and open its page in a web browser.~@
  ~@
  The first time the program is run it will create a cache of all symbols in ~
  the HyperSpec.  Subsequent runs will use this cache to look up symbol links ~
  faster.")

(defparameter *examples*
  '((".Look up STRING in the HyperSpec and open it in the default browser:" .
     "clhs string")
    ("Look up MAKE-ARRAY in a local copy of the HyperSpec and open it in lynx:" .
     "clhs --url file:///home/sjl/doc/hyperspec/ --open lynx make-array")))

(adopt:define-interface *ui*
    (:name "clhs"
     :usage "[OPTIONS] SYMBOL"
     :summary "Look up a symbol in the Common Lisp HyperSpec."
     :documentation *documentation*
     :examples *examples*)
  ((help)
   :documentation "display help and exit"
   :manual "Display help and exit."
   :long "help"
   :short #\h
   :reduce (constantly t))
  ((rebuild-cache)
   :documentation "rebuild the symbol cache"
   :manual "Rebuild the symbol cache, even if it already exists, instead of looking up a symbol."
   :long "rebuild-cache"
   :reduce (constantly t))
  ((open)
   :documentation (format nil "program to use to open hyperspec URLs (default ~A)" *default-open-command*)
   :manual (format nil "The program to use to open hyperspec URLs.  The default is: ~A" *default-open-command*)
   :long "open"
   :short #\o
   :parameter "COMMAND"
   :initial-value *default-open-command*
   :reduce #'adopt:newest)
  ((url)
   :documentation (format nil "base HyperSpec URL (default ~A)" *default-hyperspec-url*)
   :manual (format nil
                   "The base HyperSpec URL.  The default is: ~A~@
                   ~@
                   A local copy of the HyperSpec can be used with a file:// prefix."
                   *default-hyperspec-url*)
   :long "url"
   :short #\u
   :parameter "URL"
   :initial-value *default-hyperspec-url*
   :reduce #'adopt:newest))

(defun toplevel ()
  (handler-case
      (multiple-value-bind (arguments options) (adopt:parse-options *ui*)
        (when (gethash 'help options)
          (adopt:print-usage-and-exit *ui*))
        (let ((*open* (gethash 'open options))
              (*url* (gethash 'url options))
              (target (first arguments)))
          (if (gethash 'rebuild-cache options)
            (rebuild-cache)
            (progn
              (when (/= (length arguments) 1)
                (cerror "Type a symbol"
                        "Exactly one symbol to look up must be provided (got ~D: ~S)"
                        (length arguments)
                        arguments)
                (setf arguments (list (read-line))))
              (unless (run target)
                (adopt:print-error-and-exit
                  (format nil "Symbol not found: ~A~%" target)))))))
    (error (c) (adopt:print-error-and-exit c))))