问题描述(emacs-26.3, win10)：
- 安装一个甘特图插件(elgantt)时，需要依赖org-ql，该包安装后在.emacs启动文件中添加如下代码： (add-to-list 'load-path “D:/emacs/.emacs.d/elpa/elgantt/”) (require 'elgantt)
- require时报错：Debugger entered–Lisp error: (void-function -on)
- 在org-ql.el中包含"-on"的代码如下：
(defun org-ql--def-query-string-to-sexp-fn (predicates)
"Define function `org-ql--query-string-to-sexp' according to PREDICATES.
Builds the PEG expression using PREDICATES (which should be the
value of `org-ql-predicates')."
(let* ((names (--map (symbol-name (plist-get (cdr it) :name))
predicates))
(aliases (->> predicates
(--map (plist-get (cdr it) :aliases))
-non-nil
-flatten
(-map #'symbol-name)))
(predicate-names (->> (append names aliases)
-uniq
;; Sort the keywords longest-first to work around what seems to be an
;; obscure bug in `peg': when one keyword is a substring of another,
;; and the shorter one is listed first, the shorter one fails to match.
(-sort (-on #'> #'length))))
(pexs `((query (+ (and term (* [blank]))))
(term (or (and negation (list positive-term)
;; This is a bit confusing, but it seems to work. There's probably a better way.
`(pred -- (list 'not (car pred))))
positive-term))
(positive-term (or (and predicate-with-args `(pred args -- (cons (intern pred) args)))
(and predicate-without-args `(pred -- (list (intern pred))))
(and plain-string `(s -- (list org-ql-default-predicate s)))))
(plain-string (or quoted-arg unquoted-arg))
(predicate-with-args (substring predicate) ":" args)
(predicate-without-args (substring predicate) ":")
(predicate (or ,@predicate-names))
(args (list (+ (and (or keyword-arg quoted-arg unquoted-arg) (opt separator)))))
(keyword-arg (and keyword "=" `(kw -- (intern (concat ":" kw)))))
(keyword (substring (+ (not (or separator "=" "\"" (syntax-class whitespace))) (any))))
(quoted-arg "\"" (substring (+ (not (or separator "\"")) (any))) "\"")
(unquoted-arg (substring (+ (not (or separator "\"" (syntax-class whitespace))) (any))))
(negation "!")
(separator "," )))
(closure (lambda (input &optional boolean)
"Return query parsed from plain query string INPUT.
Multiple predicate-names are combined with BOOLEAN (default: `and')."
;; HACK: Silence unused lexical variable warnings.
(ignore predicates predicate-names names aliases)
(unless (s-blank-str? input)
(let* ((boolean (or boolean 'and))
(parsed-sexp
(with-temp-buffer
(insert input)
(goto-char (point-min))
;; Copied from `peg-parse'. There is no function in `peg' that
;; returns a matcher function--every entry point is a macro,
;; which means that, since we define our PEG rules at runtime when
;; predicate-names are defined, we either have to use `eval', or we
;; have to borrow some code. It ends up that we only have to
;; borrow this `with-peg-rules' call, which isn't too bad.
(eval `(with-peg-rules ,pexs
(peg-run (peg ,(caar pexs)) #'peg-signal-failure))))))
(pcase parsed-sexp
(`(,one-predicate) one-predicate)
(`(,_ . ,_) (cons boolean (reverse parsed-sexp)))
(_ nil)))))))
(fset 'org-ql--query-string-to-sexp closure)))
本人小白，看不懂lisp代码，请问该代码有bug吗？还是其它原因导致的报错。
甘特图elgantt: