adamc@350: ;;; urweb-move.el --- Buffer navigation functions for urweb-mode
adamc@350: 
adamc@350: ;; Based on urweb-mode:
adamc@350: ;; Copyright (C) 1999, 2000, 2004  Stefan Monnier <monnier@gnu.org>
adamc@350: ;;
adamc@350: ;; Modified for urweb-mode:
adamc@350: ;; Copyright (C) 2008  Adam Chlipala <adamc@hcoop.net>
adamc@350: ;;
adamc@350: ;; This program is free software; you can redistribute it and/or modify
adamc@350: ;; it under the terms of the GNU General Public License as published by
adamc@350: ;; the Free Software Foundation; either version 2 of the License, or
adamc@350: ;; (at your option) any later version.
adamc@350: ;;
adamc@350: ;; This program is distributed in the hope that it will be useful,
adamc@350: ;; but WITHOUT ANY WARRANTY; without even the implied warranty of
adamc@350: ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
adamc@350: ;; GNU General Public License for more details.
adamc@350: ;;
adamc@350: ;; You should have received a copy of the GNU General Public License
adamc@350: ;; along with this program; if not, write to the Free Software
adamc@350: ;; Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
adamc@350: 
adamc@350: 
adamc@350: ;;; Commentary:
adamc@350: 
adamc@350: 
adamc@350: ;;; Code:
adamc@350: 
adamc@350: (eval-when-compile (require 'cl))
adamc@350: (require 'urweb-util)
adamc@350: (require 'urweb-defs)
adamc@350: 
adamc@350: (defsyntax urweb-internal-syntax-table
adamc@350:   '((?_  . "w")
adamc@350:     (?'  . "w")
adamc@350:     (?.  . "w"))
adamc@350:   "Syntax table used for internal urweb-mode operation."
adamc@350:   :copy urweb-mode-syntax-table)
adamc@350: 
adamc@350: ;;; 
adamc@350: ;;; various macros
adamc@350: ;;; 
adamc@350: 
adamc@350: (defmacro urweb-with-ist (&rest r)
adamc@350:   (let ((ost-sym (make-symbol "oldtable")))
adamc@350:     `(let ((,ost-sym (syntax-table))
adamc@350: 	   (case-fold-search nil)
adamc@350: 	   (parse-sexp-lookup-properties t)
adamc@350: 	   (parse-sexp-ignore-comments t))
adamc@350:        (unwind-protect
adamc@350: 	   (progn (set-syntax-table urweb-internal-syntax-table) . ,r)
adamc@350: 	 (set-syntax-table ,ost-sym)))))
adamc@350: (def-edebug-spec urweb-with-ist t)
adamc@350: 
adamc@350: (defmacro urweb-move-if (&rest body)
adamc@350:   (let ((pt-sym (make-symbol "point"))
adamc@350: 	(res-sym (make-symbol "result")))
adamc@350:     `(let ((,pt-sym (point))
adamc@350: 	   (,res-sym ,(cons 'progn body)))
adamc@350:        (unless ,res-sym (goto-char ,pt-sym))
adamc@350:        ,res-sym)))
adamc@350: (def-edebug-spec urweb-move-if t)
adamc@350: 
adamc@350: (defmacro urweb-point-after (&rest body)
adamc@350:   `(save-excursion
adamc@350:      ,@body
adamc@350:      (point)))
adamc@350: (def-edebug-spec urweb-point-after t)
adamc@350: 
adamc@350: ;;
adamc@350: 
adamc@350: (defvar urweb-op-prec
adamc@350:   (urweb-preproc-alist
adamc@350:    '((("UNION" "INTERSECT" "EXCEPT") . 0)
adamc@350:      (("AND" "OR") . 1)
adamc@350:      ((">" ">=" "<>" "<" "<=" "=") . 4)
adamc@350:      (("+" "-" "^") . 6)
adamc@350:      (("/" "*" "%") . 7)
adamc@350:      (("++" "--") 8)
adamc@350:      (("NOT") 9)
adamc@353:      (("~") 10)))
adamc@350:   "Alist of Ur/Web infix operators and their precedence.")
adamc@350: 
adamc@350: (defconst urweb-syntax-prec
adamc@350:   (urweb-preproc-alist
adamc@350:    `(((";" ",") . 20)
adamc@350:      (("=>" "d=" "=of") . (65 . 40))
adamc@350:      ("|" . (47 . 30))
adamc@350:      (("case" "of" "fn") . 45)
adamc@350:      (("if" "then" "else" ) . 50)
adamc@350:      (("<-") . 55)
adamc@350:      ("||" . 70)
adamc@350:      ("&&" . 80)
adamc@350:      ((":" "::" ":::" ":>") . 90)
adamc@350:      ("->" . 95)
adamc@350:      ("with" . 100)
adamc@350:      (,(cons "end" urweb-begin-syms) . 10000)))
adamc@350:   "Alist of pseudo-precedence of syntactic elements.")
adamc@350: 
adamc@350: (defun urweb-op-prec (op dir)
adamc@350:   "Return the precedence of OP or nil if it's not an infix.
adamc@350: DIR should be set to BACK if you want to precedence w.r.t the left side
adamc@350:     and to FORW for the precedence w.r.t the right side.
adamc@350: This assumes that we are `looking-at' the OP."
adamc@350:   (when op
adamc@350:     (let ((sprec (cdr (assoc op urweb-syntax-prec))))
adamc@350:       (cond
adamc@350:        ((consp sprec) (if (eq dir 'back) (car sprec) (cdr sprec)))
adamc@350:        (sprec sprec)
adamc@350:        (t
adamc@350: 	(let ((prec (cdr (assoc op urweb-op-prec))))
adamc@350: 	  (when prec (+ prec 100))))))))
adamc@350: 
adamc@350: ;;
adamc@350: 
adamc@350: (defun urweb-forward-spaces () (forward-comment 100000))
adamc@350: (defun urweb-backward-spaces () (forward-comment -100000))
adamc@350: 
adamc@350: 
adamc@350: ;;
adamc@350: ;; moving forward around matching symbols
adamc@350: ;;
adamc@350: 
adamc@350: (defun urweb-looking-back-at (re)
adamc@350:   (save-excursion
adamc@350:     (when (= 0 (skip-syntax-backward "w_")) (backward-char))
adamc@350:     (looking-at re)))
adamc@350: 
adamc@350: (defun urweb-find-match-forward (this match)
adamc@350:   "Only works for word matches."
adamc@350:   (let ((level 1)
adamc@350: 	(forward-sexp-function nil)
adamc@350: 	(either (concat this "\\|" match)))
adamc@350:     (while (> level 0)
adamc@350:       (forward-sexp 1)
adamc@350:       (while (not (or (eobp) (urweb-looking-back-at either)))
adamc@350: 	(condition-case () (forward-sexp 1) (error (forward-char 1))))
adamc@350:       (setq level
adamc@350: 	    (cond
adamc@350: 	     ((and (eobp) (> level 1)) (error "Unbalanced"))
adamc@350: 	     ((urweb-looking-back-at this) (1+ level))
adamc@350: 	     ((urweb-looking-back-at match) (1- level))
adamc@350: 	     (t (error "Unbalanced")))))
adamc@350:     t))
adamc@350: 
adamc@350: (defun urweb-find-match-backward (this match)
adamc@350:   (let ((level 1)
adamc@350: 	(forward-sexp-function nil)
adamc@350: 	(either (concat this "\\|" match)))
adamc@350:     (while (> level 0)
adamc@350:       (backward-sexp 1)
adamc@350:       (while (not (or (bobp) (looking-at either)))
adamc@350: 	(condition-case () (backward-sexp 1) (error (backward-char 1))))
adamc@350:       (setq level
adamc@350: 	    (cond
adamc@350: 	     ((and (bobp) (> level 1)) (error "Unbalanced"))
adamc@350: 	     ((looking-at this) (1+ level))
adamc@350: 	     ((looking-at match) (1- level))
adamc@350: 	     (t (error "Unbalanced")))))
adamc@350:     t))
adamc@350: 
adamc@350: ;;; 
adamc@350: ;;; read a symbol, including the special "op <sym>" case
adamc@350: ;;; 
adamc@350: 
adamc@350: (defmacro urweb-move-read (&rest body)
adamc@350:   (let ((pt-sym (make-symbol "point")))
adamc@350:     `(let ((,pt-sym (point)))
adamc@350:        ,@body
adamc@350:        (when (/= (point) ,pt-sym)
adamc@350: 	 (buffer-substring-no-properties (point) ,pt-sym)))))
adamc@350: (def-edebug-spec urweb-move-read t)
adamc@350: 
adamc@350: (defun urweb-poly-equal-p ()
adamc@350:   (< (urweb-point-after (re-search-backward urweb-=-starter-re nil 'move))
adamc@350:      (urweb-point-after (re-search-backward "=" nil 'move))))
adamc@350: 
adamc@350: (defun urweb-nested-of-p ()
adamc@350:   (< (urweb-point-after
adamc@350:       (re-search-backward urweb-non-nested-of-starter-re nil 'move))
adamc@350:      (urweb-point-after (re-search-backward "\\<case\\>" nil 'move))))
adamc@350: 
adamc@350: (defun urweb-forward-sym-1 ()
adamc@350:   (or (/= 0 (skip-syntax-forward "'w_"))
adamc@350:       (/= 0 (skip-syntax-forward ".'"))))
adamc@350: (defun urweb-forward-sym ()
adamc@350:   (let ((sym (urweb-move-read (urweb-forward-sym-1))))
adamc@350:     (cond
adamc@350:      ((equal "op" sym)
adamc@350:       (urweb-forward-spaces)
adamc@350:       (concat "op " (or (urweb-move-read (urweb-forward-sym-1)) "")))
adamc@350:      ((equal sym "=")
adamc@350:       (save-excursion
adamc@350: 	(urweb-backward-sym-1)
adamc@350: 	(if (urweb-poly-equal-p) "=" "d=")))
adamc@350:      ((equal sym "of")
adamc@350:       (save-excursion
adamc@350: 	(urweb-backward-sym-1)
adamc@350: 	(if (urweb-nested-of-p) "of" "=of")))
adamc@350:      ;; ((equal sym "datatype")
adamc@350:      ;;  (save-excursion
adamc@350:      ;; 	(urweb-backward-sym-1)
adamc@350:      ;; 	(urweb-backward-spaces)
adamc@350:      ;; 	(if (eq (preceding-char) ?=) "=datatype" sym)))
adamc@350:      (t sym))))
adamc@350: 
adamc@350: (defun urweb-backward-sym-1 ()
adamc@350:   (or (/= 0 (skip-syntax-backward ".'"))
adamc@350:       (/= 0 (skip-syntax-backward "'w_"))))
adamc@350: (defun urweb-backward-sym ()
adamc@350:   (let ((sym (urweb-move-read (urweb-backward-sym-1))))
adamc@350:     (when sym
adamc@350:       ;; FIXME: what should we do if `sym' = "op" ?
adamc@350:       (let ((point (point)))
adamc@350: 	(urweb-backward-spaces)
adamc@350: 	(if (equal "op" (urweb-move-read (urweb-backward-sym-1)))
adamc@350: 	    (concat "op " sym)
adamc@350: 	  (goto-char point)
adamc@350: 	  (cond
adamc@350: 	   ((string= sym "=") (if (urweb-poly-equal-p) "=" "d="))
adamc@350: 	   ((string= sym "of") (if (urweb-nested-of-p) "of" "=of"))
adamc@350: 	   ;; ((string= sym "datatype")
adamc@350: 	   ;;  (save-excursion (urweb-backward-spaces)
adamc@350: 	   ;; 		    (if (eq (preceding-char) ?=) "=datatype" sym)))
adamc@350: 	   (t sym)))))))
adamc@350:     
adamc@350: 
adamc@350: (defun urweb-backward-sexp (prec)
adamc@350:   "Move one sexp backward if possible, or one char else.
adamc@350: Returns t if the move indeed moved through one sexp and nil if not.
adamc@350: PREC is the precedence currently looked for."
adamc@350:   (let ((parse-sexp-lookup-properties t)
adamc@350: 	(parse-sexp-ignore-comments t))
adamc@350:     (urweb-backward-spaces)
adamc@350:     (let* ((op (urweb-backward-sym))
adamc@350: 	   (op-prec (urweb-op-prec op 'back))
adamc@350: 	   match)
adamc@350:       (cond
adamc@350:        ((not op)
adamc@350: 	(let ((point (point)))
adamc@350: 	  (ignore-errors (let ((forward-sexp-function nil)) (backward-sexp 1)))
adamc@350: 	  (if (/= point (point)) t (ignore-errors (backward-char 1)) nil)))
adamc@350:        ;; stop as soon as precedence is smaller than `prec'
adamc@350:        ((and prec op-prec (>= prec op-prec)) nil)
adamc@350:        ;; special rules for nested constructs like if..then..else
adamc@350:        ((and (or (not prec) (and prec op-prec))
adamc@350: 	     (setq match (second (assoc op urweb-close-paren))))
adamc@350: 	(urweb-find-match-backward (concat "\\<" op "\\>") match))
adamc@350:        ;; don't back over open-parens
adamc@350:        ((assoc op urweb-open-paren) nil)
adamc@350:        ;; infix ops precedence
adamc@350:        ((and prec op-prec) (< prec op-prec))
adamc@350:        ;; [ prec = nil ]  a new operator, let's skip the sexps until the next
adamc@350:        (op-prec (while (urweb-move-if (urweb-backward-sexp op-prec))) t)
adamc@350:        ;; special symbols indicating we're getting out of a nesting level
adamc@350:        ((string-match urweb-sexp-head-symbols-re op) nil)
adamc@350:        ;; if the op was not alphanum, then we still have to do the backward-sexp
adamc@350:        ;; this reproduces the usual backward-sexp, but it might be bogus
adamc@350:        ;; in this case since !@$% is a perfectly fine symbol
adamc@350:        (t t))))) ;(or (string-match "\\sw" op) (urweb-backward-sexp prec))
adamc@350: 
adamc@350: (defun urweb-forward-sexp (prec)
adamc@350:   "Moves one sexp forward if possible, or one char else.
adamc@350: Returns T if the move indeed moved through one sexp and NIL if not."
adamc@350:   (let ((parse-sexp-lookup-properties t)
adamc@350: 	(parse-sexp-ignore-comments t))
adamc@350:     (urweb-forward-spaces)
adamc@350:     (let* ((op (urweb-forward-sym))
adamc@350: 	   (op-prec (urweb-op-prec op 'forw))
adamc@350: 	   match)
adamc@350:       (cond
adamc@350:        ((not op)
adamc@350: 	(let ((point (point)))
adamc@350: 	  (ignore-errors (let ((forward-sexp-function nil)) (forward-sexp 1)))
adamc@350: 	  (if (/= point (point)) t (forward-char 1) nil)))
adamc@350:        ;; stop as soon as precedence is smaller than `prec'
adamc@350:        ((and prec op-prec (>= prec op-prec)) nil)
adamc@350:        ;; special rules for nested constructs like if..then..else
adamc@350:        ((and (or (not prec) (and prec op-prec))
adamc@350: 	     (setq match (cdr (assoc op urweb-open-paren))))
adamc@350: 	(urweb-find-match-forward (first match) (second match)))
adamc@350:        ;; don't forw over close-parens
adamc@350:        ((assoc op urweb-close-paren) nil)
adamc@350:        ;; infix ops precedence
adamc@350:        ((and prec op-prec) (< prec op-prec))
adamc@350:        ;; [ prec = nil ]  a new operator, let's skip the sexps until the next
adamc@350:        (op-prec (while (urweb-move-if (urweb-forward-sexp op-prec))) t)
adamc@350:        ;; special symbols indicating we're getting out of a nesting level
adamc@350:        ((string-match urweb-sexp-head-symbols-re op) nil)
adamc@350:        ;; if the op was not alphanum, then we still have to do the backward-sexp
adamc@350:        ;; this reproduces the usual backward-sexp, but it might be bogus
adamc@350:        ;; in this case since !@$% is a perfectly fine symbol
adamc@350:        (t t))))) ;(or (string-match "\\sw" op) (urweb-backward-sexp prec))
adamc@350: 
adamc@350: (defun urweb-in-word-p ()
adamc@350:   (and (eq ?w (char-syntax (or (char-before) ? )))
adamc@350:        (eq ?w (char-syntax (or (char-after) ? )))))
adamc@350: 
adamc@350: (defun urweb-user-backward-sexp (&optional count)
adamc@350:   "Like `backward-sexp' but tailored to the Ur/Web syntax."
adamc@350:   (interactive "p")
adamc@350:   (unless count (setq count 1))
adamc@350:   (urweb-with-ist
adamc@350:    (let ((point (point)))
adamc@350:      (if (< count 0) (urweb-user-forward-sexp (- count))
adamc@350:        (when (urweb-in-word-p) (forward-word 1))
adamc@350:        (dotimes (i count)
adamc@350: 	 (unless (urweb-backward-sexp nil)
adamc@350: 	   (goto-char point)
adamc@350: 	   (error "Containing expression ends prematurely")))))))
adamc@350: 
adamc@350: (defun urweb-user-forward-sexp (&optional count)
adamc@350:   "Like `forward-sexp' but tailored to the Ur/Web syntax."
adamc@350:   (interactive "p")
adamc@350:   (unless count (setq count 1))
adamc@350:   (urweb-with-ist
adamc@350:    (let ((point (point)))
adamc@350:      (if (< count 0) (urweb-user-backward-sexp (- count))
adamc@350:        (when (urweb-in-word-p) (backward-word 1))
adamc@350:        (dotimes (i count)
adamc@350: 	 (unless (urweb-forward-sexp nil)
adamc@350: 	   (goto-char point)
adamc@350: 	   (error "Containing expression ends prematurely")))))))
adamc@350: 
adamc@350: ;;(defun urweb-forward-thing ()
adamc@350: ;;  (if (= ?w (char-syntax (char-after))) (forward-word 1) (forward-char 1)))
adamc@350: 
adamc@350: (defun urweb-backward-arg () (urweb-backward-sexp 1000))
adamc@350: (defun urweb-forward-arg () (urweb-forward-sexp 1000))
adamc@350: 
adamc@350: 
adamc@350: (provide 'urweb-move)
adamc@350: 
adamc@350: ;;; urweb-move.el ends here