;; Rx translates a sexp notation for regular expressions into the
;; usual string notation. The translation can be done at compile-time
-;; by using the `rx' macro. It can be done at run-time by calling
-;; function `rx-to-string'. See the documentation of `rx' for a
-;; complete description of the sexp notation.
+;; by using the `rx' macro. The `regexp' and `literal' forms accept
+;; non-constant expressions, in which case `rx' will translate to a
+;; `concat' expression. Translation can be done fully at run time by
+;; calling function `rx-to-string'. See the documentation of `rx' for
+;; a complete description of the sexp notation.
;;
;; Some examples of string regexps and their sexp counterparts:
;;
;; "^[a-z]*"
-;; (rx (and line-start (0+ (in "a-z"))))
+;; (rx line-start (0+ (in "a-z")))
;;
;; "\n[^ \t]"
-;; (rx (and "\n" (not (any " \t"))))
+;; (rx ?\n (not (in " \t")))
;;
;; "\\*\\*\\* EOOH \\*\\*\\*\n"
;; (rx "*** EOOH ***\n")
;;
;; "\\<\\(catch\\|finally\\)\\>[^_]"
-;; (rx (and word-start (submatch (or "catch" "finally")) word-end
-;; (not (any ?_))))
+;; (rx word-start (submatch (or "catch" "finally")) word-end
+;; (not (in ?_)))
;;
-;; "[ \t\n]*:\\([^:]+\\|$\\)"
-;; (rx (and (zero-or-more (in " \t\n")) ":"
-;; (submatch (or line-end (one-or-more (not (any ?:)))))))
+;; "[ \t\n]*:\\($\\|[^:]+\\)"
+;; (rx (* (in " \t\n")) ":"
+;; (submatch (or line-end (+ (not (in ?:))))))
;;
-;; "^content-transfer-encoding:\\(\n?[\t ]\\)*quoted-printable\\(\n?[\t ]\\)*"
-;; (rx (and line-start
-;; "content-transfer-encoding:"
-;; (+ (? ?\n)) (any " \t")
-;; "quoted-printable"
-;; (+ (? ?\n)) (any " \t"))
+;; "^content-transfer-encoding:\\(?:\n?[\t ]\\)*quoted-printable\\(?:\n?[\t ]\\)*"
+;; (rx line-start
+;; "content-transfer-encoding:"
+;; (* (? ?\n) (in " \t"))
+;; "quoted-printable"
+;; (* (? ?\n) (in " \t")))
;;
;; (concat "^\\(?:" something-else "\\)")
-;; (rx (and line-start (eval something-else))), statically or
-;; (rx-to-string '(and line-start ,something-else)), dynamically.
+;; (rx line-start (regexp something-else))
;;
;; (regexp-opt '(STRING1 STRING2 ...))
;; (rx (or STRING1 STRING2 ...)), or in other words, `or' automatically
;; calls `regexp-opt' as needed.
;;
;; "^;;\\s-*\n\\|^\n"
-;; (rx (or (and line-start ";;" (0+ space) ?\n)
-;; (and line-start ?\n)))
+;; (rx (or (seq line-start ";;" (0+ space) ?\n)
+;; (seq line-start ?\n)))
;;
;; "\\$[I]d: [^ ]+ \\([^ ]+\\) "
-;; (rx (and "$Id: "
-;; (1+ (not (in " ")))
-;; " "
-;; (submatch (1+ (not (in " "))))
-;; " "))
+;; (rx "$Id: "
+;; (1+ (not (in " ")))
+;; " "
+;; (submatch (1+ (not (in " "))))
+;; " ")
;;
;; "\\\\\\\\\\[\\w+"
-;; (rx (and ?\\ ?\\ ?\[ (1+ word)))
+;; (rx "\\\\[" (1+ word))
;;
;; etc.
(not-syntax . (rx-not-syntax 1 1)) ; sregex
(category . (rx-category 1 1 rx-check-category))
(eval . (rx-eval 1 1))
+ (literal . (rx-literal 1 1 stringp))
(regexp . (rx-regexp 1 1 stringp))
(regex . regexp) ; sregex
(digit . "[[:digit:]]")
"Non-nil means produce greedy regular expressions for `zero-or-one',
`zero-or-more', and `one-or-more'. Dynamically bound.")
+(defvar rx--compile-to-lisp nil
+ "Nil means return a regexp as a string.
+Non-nil means we may return a lisp form which produces a
+string (used for `rx' macro).")
(defun rx-info (op head)
"Return parsing/code generation info for OP.
(> nargs max-args))
(error "rx form `%s' accepts at most %d args"
(car form) max-args))
- (when (not (null type-pred))
+ (when type-pred
(dolist (sub-form (cdr form))
(unless (funcall type-pred sub-form)
(error "rx form `%s' requires args satisfying `%s'"
;; for concatenation
((eq group ':)
(if (rx-atomic-p
- (if (string-match
- "\\(?:[?*+]\\??\\|\\\\{[0-9]*,?[0-9]*\\\\}\\)\\'" regexp)
+ (if (and (stringp regexp)
+ (string-match
+ "\\(?:[?*+]\\??\\|\\\\{[0-9]*,?[0-9]*\\\\}\\)\\'" regexp))
(substring regexp 0 (match-beginning 0))
regexp))
(setq group nil)))
;; do anyway
((eq group t))
((rx-atomic-p regexp t) (setq group nil)))
- (if group
- (concat "\\(?:" regexp "\\)")
- regexp))
+ (cond ((and group (stringp regexp))
+ (concat "\\(?:" regexp "\\)"))
+ (group `("\\(?:" ,@regexp "\\)"))
+ (t regexp)))
(defvar rx-parent)
FORM is of the form `(and FORM1 ...)'."
(rx-check form)
(rx-group-if
- (mapconcat (lambda (x) (rx-form x ':)) (cdr form) nil)
+ (rx--subforms (cdr form) ':)
(and (memq rx-parent '(* t)) rx-parent)))
((null (cdr form)) regexp-unmatchable)
((cl-every #'stringp (cdr form))
(regexp-opt (cdr form) nil t))
- (t (mapconcat (lambda (x) (rx-form x '|)) (cdr form) "\\|")))
+ (t (rx--subforms (cdr form) '| "\\|")))
(and (memq rx-parent '(: * t)) rx-parent)))
(unless (and (integerp (nth 1 form))
(> (nth 1 form) 0))
(error "rx `=' requires positive integer first arg"))
- (format "%s\\{%d\\}" (rx-form (nth 2 form) '*) (nth 1 form)))
+ (let ((subform (rx-form (nth 2 form) '*)))
+ (if (stringp subform)
+ (format "%s\\{%d\\}" subform (nth 1 form))
+ `(,@subform ,(format "\\{%d\\}" (nth 1 form))))))
(defun rx->= (form)
(unless (and (integerp (nth 1 form))
(> (nth 1 form) 0))
(error "rx `>=' requires positive integer first arg"))
- (format "%s\\{%d,\\}" (rx-form (nth 2 form) '*) (nth 1 form)))
+ (let ((subform (rx-form (nth 2 form) '*)))
+ (if (stringp subform)
+ (format "%s\\{%d,\\}" subform (nth 1 form))
+ `(,@subform ,(format "\\{%d,\\}" (nth 1 form))))))
(defun rx-** (form)
(unless (and (integerp (nth 1 form))
(> (nth 1 form) 0))
(error "rx `repeat' requires positive integer first arg"))
- (format "%s\\{%d\\}" (rx-form (nth 2 form) '*) (nth 1 form)))
+ (let ((subform (rx-form (nth 2 form) '*)))
+ (if (stringp subform)
+ (format "%s\\{%d\\}" subform (nth 1 form))
+ `(,@subform ,(format "\\{%d\\}" (nth 1 form))))))
((or (not (integerp (nth 2 form)))
(< (nth 2 form) 0)
(not (integerp (nth 1 form)))
(< (nth 2 form) (nth 1 form)))
(error "rx `repeat' range error"))
(t
- (format "%s\\{%d,%d\\}" (rx-form (nth 3 form) '*)
- (nth 1 form) (nth 2 form)))))
+ (let ((subform (rx-form (nth 3 form) '*)))
+ (if (stringp subform)
+ (format "%s\\{%d,%d\\}" subform (nth 1 form) (nth 2 form))
+ `(,@subform ,(format "\\{%d,%d\\}" (nth 1 form) (nth 2 form))))))))
(defun rx-submatch (form)
"Parse and produce code from FORM, which is `(submatch ...)'."
- (concat "\\("
- (if (= 2 (length form))
- ;; Only one sub-form.
- (rx-form (cadr form))
- ;; Several sub-forms implicitly concatenated.
- (mapconcat (lambda (re) (rx-form re ':)) (cdr form) nil))
- "\\)"))
+ (let ((subforms (rx--subforms (cdr form) ':)))
+ (if (stringp subforms)
+ (concat "\\(" subforms "\\)")
+ `("\\(" ,@subforms "\\)"))))
(defun rx-submatch-n (form)
"Parse and produce code from FORM, which is `(submatch-n N ...)'."
- (let ((n (nth 1 form)))
+ (let ((n (nth 1 form))
+ (subforms (rx--subforms (cddr form) ':)))
(unless (and (integerp n) (> n 0))
(error "rx `submatch-n' argument must be positive"))
- (concat "\\(?" (number-to-string n) ":"
- (if (= 3 (length form))
- ;; Only one sub-form.
- (rx-form (nth 2 form))
- ;; Several sub-forms implicitly concatenated.
- (mapconcat (lambda (re) (rx-form re ':)) (cddr form) nil))
- "\\)")))
+ (if (stringp subforms)
+ (concat "\\(?" (number-to-string n) ":" subforms "\\)")
+ `("\\(?" ,(number-to-string n) ":" ,@subforms "\\)"))))
(defun rx-backref (form)
"Parse and produce code from FORM, which is `(backref N)'."
(t "?")))
(op (cond ((memq (car form) '(* *? 0+ zero-or-more)) "*")
((memq (car form) '(+ +? 1+ one-or-more)) "+")
- (t "?"))))
+ (t "?")))
+ (subform (rx-form (cadr form) '*)))
(rx-group-if
- (concat (rx-form (cadr form) '*) op suffix)
+ (if (stringp subform)
+ (concat subform op suffix)
+ `(,@subform ,(concat op suffix)))
(and (memq rx-parent '(t *)) rx-parent))))
be detected without much effort. A guarantee of no false
negatives would require a theoretic specification of the set
of all atomic regexps."
- (let ((l (length r)))
- (cond
- ((<= l 1))
- ((= l 2) (= (aref r 0) ?\\))
- ((= l 3) (string-match "\\`\\(?:\\\\[cCsS_]\\|\\[[^^]\\]\\)" r))
- ((null lax)
+ (if (and rx--compile-to-lisp
+ (not (stringp r)))
+ nil ;; Runtime value, we must assume non-atomic.
+ (let ((l (length r)))
(cond
- ((string-match "\\`\\[\\^?]?\\(?:\\[:[a-z]+:]\\|[^]]\\)*]\\'" r))
- ((string-match "\\`\\\\(\\(?:[^\\]\\|\\\\[^)]\\)*\\\\)\\'" r)))))))
+ ((<= l 1))
+ ((= l 2) (= (aref r 0) ?\\))
+ ((= l 3) (string-match "\\`\\(?:\\\\[cCsS_]\\|\\[[^^]\\]\\)" r))
+ ((null lax)
+ (cond
+ ((string-match "\\`\\[\\^?]?\\(?:\\[:[a-z]+:]\\|[^]]\\)*]\\'" r))
+ ((string-match "\\`\\\\(\\(?:[^\\]\\|\\\\[^)]\\)*\\\\)\\'" r))))))))
(defun rx-syntax (form)
(defun rx-regexp (form)
"Parse and produce code from FORM, which is `(regexp STRING)'."
- (rx-check form)
- (rx-group-if (cadr form) rx-parent))
-
+ (cond ((stringp form)
+ (rx-group-if (cadr form) rx-parent))
+ (rx--compile-to-lisp
+ ;; Always group non-string forms, since we can't be sure they
+ ;; are atomic.
+ (rx-group-if (cdr form) t))
+ (t (rx-check form))))
+
+(defun rx-literal (form)
+ "Parse and produce code from FORM, which is `(literal STRING-EXP)'."
+ (cond ((stringp form)
+ ;; This is allowed, but makes little sense, you could just
+ ;; use STRING directly.
+ (rx-group-if (regexp-quote (cadr form)) rx-parent))
+ (rx--compile-to-lisp
+ (rx-group-if `((regexp-quote ,(cadr form))) rx-parent))
+ (t (rx-check form))))
(defun rx-form (form &optional parent)
"Parse and produce code for regular expression FORM.
(t
(error "rx syntax error at `%s'" form)))))
+(defun rx--subforms (subforms &optional parent separator)
+ "Produce code for regular expressions SUBFORMS.
+SUBFORMS is a list of regular expression sexps.
+PARENT controls grouping, as in `rx-form'.
+Insert SEPARATOR between the code from each of SUBFORMS."
+ (if (null (cdr subforms))
+ ;; Zero or one forms, no need for grouping.
+ (and subforms (rx-form (car subforms)))
+ (let ((listify (lambda (x)
+ (if (listp x) (copy-sequence x)
+ (list x)))))
+ (setq subforms (mapcar (lambda (x) (rx-form x parent)) subforms))
+ (cond ((or (not rx--compile-to-lisp)
+ (cl-every #'stringp subforms))
+ (mapconcat #'identity subforms separator))
+ (separator
+ (nconc (funcall listify (car subforms))
+ (mapcan (lambda (x)
+ (cons separator (funcall listify x)))
+ (cdr subforms))))
+ (t (mapcan listify subforms))))))
+
;;;###autoload
(defun rx-to-string (form &optional no-group)
"Parse and produce code for regular expression FORM.
FORM is a regular expression in sexp form.
-NO-GROUP non-nil means don't put shy groups around the result."
+NO-GROUP non-nil means don't put shy groups around the result.
+
+In contrast to the `rx' macro, subforms `literal' and `regexp'
+will not accept non-string arguments, i.e., (literal STRING)
+becomes just a more verbose version of STRING."
(rx-group-if (rx-form form) (null no-group)))
REGEXPS is a non-empty sequence of forms of the sort listed below.
Note that `rx' is a Lisp macro; when used in a Lisp program being
-compiled, the translation is performed by the compiler.
-See `rx-to-string' for how to do such a translation at run-time.
+compiled, the translation is performed by the compiler. The
+`literal' and `regexp' forms accept subforms that will evaluate
+to strings, in addition to constant strings. If REGEXPS include
+such forms, then the result is an expression which returns a
+regexp string, rather than a regexp string directly. See
+`rx-to-string' for performing translation completely at run time.
The following are valid subforms of regular expressions in sexp
notation.
`(backref N)'
matches what was matched previously by submatch N.
+`(literal STRING-EXPR)'
+ matches STRING-EXPR literally, where STRING-EXPR is any lisp
+ expression that evaluates to a string.
+
+`(regexp REGEXP-EXPR)'
+ include REGEXP-EXPR in string notation in the result, where
+ REGEXP-EXPR is any lisp expression that evaluates to a
+ string containing a valid regexp.
+
`(eval FORM)'
evaluate FORM and insert result. If result is a string,
- `regexp-quote' it.
-
-`(regexp REGEXP)'
- include REGEXP in string notation in the result."
- (cond ((null regexps)
- (error "No regexp"))
- ((cdr regexps)
- (rx-to-string `(and ,@regexps) t))
- (t
- (rx-to-string (car regexps) t))))
+ `regexp-quote' it. Note that FORM is evaluated during
+ macroexpansion."
+ (let* ((rx--compile-to-lisp t)
+ (re (cond ((null regexps)
+ (error "No regexp"))
+ ((cdr regexps)
+ (rx-to-string `(and ,@regexps) t))
+ (t
+ (rx-to-string (car regexps) t)))))
+ (if (stringp re)
+ re
+ `(concat ,@re))))
(pcase-defmacro rx (&rest regexps)
for var in vars
collect `(app (match-string ,i) ,var)))))
\f
-;; ;; sregex.el replacement
-
-;; ;;;###autoload (provide 'sregex)
-;; ;;;###autoload (autoload 'sregex "rx")
-;; (defalias 'sregex 'rx-to-string)
-;; ;;;###autoload (autoload 'sregexq "rx" nil nil 'macro)
-;; (defalias 'sregexq 'rx)
-\f
(provide 'rx)
;;; rx.el ends here
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