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Bunch of minor updates to decl-scan module. #1456

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Bunch of minor updates to decl-scan module. #1456

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53e51fe
Update documentation
czipperz Nov 14, 2016
64a1112
Fix `haskell-ds-whitespace-p`
czipperz Nov 14, 2016
031856b
Skipping comments skips their open/close delimiters as well
czipperz Nov 14, 2016
9d049bc
`haskell-ds-comment-p` only works on current point.
czipperz Nov 14, 2016
8103e59
`haskell-ds-line-commented-p` no longer moves point.
czipperz Nov 14, 2016
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47 changes: 21 additions & 26 deletions haskell-decl-scan.el
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Original file line number Diff line number Diff line change
Expand Up @@ -194,17 +194,18 @@ current line that starts with REGEXP and is not in `font-lock-comment-face'."
'font-lock-comment-face)))))

(defun haskell-ds-move-to-start-regexp-skipping-comments (inc regexp)
"Like haskell-ds-move-to-start-regexp, but uses syntax-ppss to
skip comments"
"Like haskell-ds-move-to-start-regexp, but skips comments."
(let (p)
(cl-loop
do (setq p (point))
(haskell-ds-move-to-start-regexp inc regexp)
while (and (nth 4 (syntax-ppss))
while (and (not (haskell-ds-whitespace-p))
(haskell-ds-comment-p)
(/= p (point))))))

(defvar literate-haskell-ds-line-prefix "> ?"
"Regexp matching start of a line of Bird-style literate code.

Current value is \"> \" as we assume top-level declarations start
at column 3. Must not contain the special \"^\" regexp as we may
not use the regexp at the start of a regexp string. Note this is
Expand All @@ -217,10 +218,10 @@ only for `imenu' support.")
(concat literate-haskell-ds-line-prefix haskell-ds-start-decl-re)
"The regexp that starts a Bird-style literate Haskell declaration.")

(defun haskell-ds-whitespace-p (char)
"Test if CHAR is a whitespace character."
;; the nil is a bob/eob test
(member char '(nil ?\t ?\n ?\ )))
(defun haskell-ds-whitespace-p ()
"Test if PT is at a whitespace character."
(or (eolp)
(equal (string-to-syntax " ") (syntax-after (point)))))

(defun haskell-ds-move-to-decl (direction bird-literate fix)
"General function for moving to the start of a declaration,
Expand Down Expand Up @@ -356,20 +357,15 @@ there."
(interactive)
(haskell-ds-move-to-decl nil (haskell-ds-bird-p) nil))

(defun haskell-ds-comment-p
(&optional
pt)
"Test if the cursor is on whitespace or a comment.

`PT' defaults to `(point)'"
(defun haskell-ds-comment-p ()
"Test if the cursor is on whitespace or a comment."
;; ensure result is `t' or `nil' instead of just truthy
(if (or
;; is cursor on whitespace
(haskell-ds-whitespace-p (following-char))
(haskell-ds-whitespace-p)
;; http://emacs.stackexchange.com/questions/14269/how-to-detect-if-the-point-is-within-a-comment-area
;; is cursor at begging, inside, or end of comment
(let ((fontfaces (get-text-property (or pt
(point)) 'face)))
(let ((fontfaces (get-text-property (point) 'face)))
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I can't add comment on a line that follows, so I'm putting it here: comments in haskell have structure and we use more faces than just font-lock-comment-face: haskell-pragma-face, haskell-liquid-haskell-annotation-face, haskell-literate-comment-face. Sometimes we also add (:weight bold) and (:slant italic).

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The weight and slant already work. I can add these other faces to the member test if you want.

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Yes, they have to be there. Otherwise declscan will not work.

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Thanks for the help.

(when (not (listp fontfaces))
(setf fontfaces (list fontfaces)))
(delq nil (mapcar
Expand All @@ -382,18 +378,17 @@ there."
nil))

(defun haskell-ds-line-commented-p ()
"Tests if all characters from `point' to `end-of-line' pass
`haskell-ds-comment-p'"
(let ((r t))
(while (and r (not (eolp)))
(if (not (haskell-ds-comment-p))
(setq r nil))
(forward-char))
r))
"Test if all characters from `point' to `end-of-line' pass `haskell-ds-comment-p'."
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This function is horrible. The way to find end of current comment is to use (parse-partial-sexp (point) (point-max) nil nil (syntax-ppss) 'syntax-table). Examples are in haskell-font-lock.el.

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The only usage of this function is to go back to the end of a definition. That requires going through all lines that are composed only of white space and comments.

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Use (parse-partial-sexp (point) (point-max) nil nil (syntax-ppss) 'syntax-table) for this purpose.

(save-excursion
(let ((r t))
(while (and r (not (eolp)))
(if (not (haskell-ds-comment-p))
(setq r nil))
(forward-char))
r)))

(defun haskell-ds-forward-decl ()
"Move forward to the first character that starts a top-level
declaration. As `haskell-ds-backward-decl' but forward."
"Move forward to the end of the top-level declaration."
(interactive)
(let ((p (point)) b e empty was-at-bob)
;; Go back to beginning of defun, then go to beginning of next
Expand Down