(eval-when-compile (require 'cl))
(require 'custom)
(require 'font-lock)
(require 'cc-mode)
(defgroup cwarn nil
"Highlight suspicious C and C++ constructions."
:version "21.1"
:link '(url-link "http://www.andersl.com/emacs")
:group 'faces)
(defvar cwarn-mode nil
"*Non-nil when Cwarn mode is active.
Never set this variable directly, use the command `cwarn-mode'
instead.")
(defcustom cwarn-configuration
'((c-mode (not reference))
(c++-mode t))
"*List of items each describing which features are enable for a mode.
Each item is on the form (mode featurelist), where featurelist can be
on one of three forms:
* A list of enabled features.
* A list starting with the atom `not' followed by the features
which are not enabled.
* The atom t, that represent that all features are enabled.
See variable `cwarn-font-lock-feature-keywords-alist' for available
features."
:type '(repeat sexp)
:group 'cwarn)
(defcustom cwarn-font-lock-feature-keywords-alist
'((assign . cwarn-font-lock-assignment-keywords)
(semicolon . cwarn-font-lock-semicolon-keywords)
(reference . cwarn-font-lock-reference-keywords))
"An alist mapping a CWarn feature to font-lock keywords.
The keywords could either a font-lock keyword list or a symbol.
If it is a symbol it is assumed to be a variable containing a font-lock
keyword list."
:type '(alist :key-type (choice (const assign)
(const semicolon)
(const reference))
:value-type (sexp :tag "Value"))
:group 'cwarn)
(defcustom cwarn-verbose t
"*When nil, CWarn mode will not generate any messages.
Currently, messages are generated when the mode is activated and
deactivated."
:group 'cwarn
:type 'boolean)
(defcustom cwarn-mode-text " CWarn"
"*String to display in the mode line when CWarn mode is active.
\(When the string is not empty, make sure that it has a leading space.)"
:tag "CWarn mode text" :group 'cwarn
:type 'string)
(defcustom cwarn-load-hook nil
"*Functions to run when CWarn mode is first loaded."
:tag "Load Hook"
:group 'cwarn
:type 'hook)
(define-minor-mode cwarn-mode
"Minor mode that highlights suspicious C and C++ constructions.
Note, in addition to enabling this minor mode, the major mode must
be included in the variable `cwarn-configuration'. By default C and
C++ modes are included.
With ARG, turn CWarn mode on if and only if arg is positive."
:group 'cwarn :lighter cwarn-mode-text
(cwarn-font-lock-keywords cwarn-mode)
(if font-lock-mode (font-lock-fontify-buffer)))
(defun turn-on-cwarn-mode ()
"Turn on CWarn mode.
This function is designed to be added to hooks, for example:
(add-hook 'c-mode-hook 'turn-on-cwarn-mode)"
(cwarn-mode 1))
(defun cwarn-is-enabled (mode &optional feature)
"Non-nil if CWarn FEATURE is enabled for MODE.
feature is an atom representing one construction to highlight.
Check if any feature is enabled for MODE if no feature is specified.
The valid features are described by the variable
`cwarn-font-lock-feature-keywords-alist'."
(let ((mode-configuraion (assq mode cwarn-configuration)))
(and mode-configuraion
(or (null feature)
(let ((list-or-t (nth 1 mode-configuraion)))
(or (eq list-or-t t)
(if (eq (car-safe list-or-t) 'not)
(not (memq feature (cdr list-or-t)))
(memq feature list-or-t))))))))
(defun cwarn-inside-macro ()
"True if point is inside a C macro definition."
(save-excursion
(beginning-of-line)
(while (eq (char-before (1- (point))) ?\\)
(forward-line -1))
(back-to-indentation)
(eq (char-after) ?#)))
(defun cwarn-font-lock-keywords (addp)
"Install/Remove keywords into current buffer.
If ADDP is non-nil, install else remove."
(dolist (pair cwarn-font-lock-feature-keywords-alist)
(let ((feature (car pair))
(keywords (cdr pair)))
(if (not (listp keywords))
(setq keywords (symbol-value keywords)))
(if (cwarn-is-enabled major-mode feature)
(funcall (if addp 'font-lock-add-keywords 'font-lock-remove-keywords)
nil keywords)))))
(if (not (fboundp 'c-at-toplevel-p))
(defun c-at-toplevel-p ()
"Return a determination as to whether point is at the `top-level'.
Being at the top-level means that point is either outside any
enclosing block (such function definition), or inside a class
definition, but outside any method blocks.
If point is not at the top-level (e.g. it is inside a method
definition), then nil is returned. Otherwise, if point is at a
top-level not enclosed within a class definition, t is returned.
Otherwise, a 2-vector is returned where the zeroth element is the
buffer position of the start of the class declaration, and the first
element is the buffer position of the enclosing class' opening
brace."
(let ((state (c-parse-state)))
(or (not (c-most-enclosing-brace state))
(c-search-uplist-for-classkey state))))
)
(defmacro cwarn-font-lock-match (re &rest body)
"Match RE but only if BODY holds."
`(let ((res nil))
(while
(progn
(setq res (re-search-forward ,re limit t))
(and res
(save-excursion
(when (match-beginning 1) (goto-char (match-beginning 1)))
(condition-case nil (not (save-match-data
,@body))
(error t))))))
res))
(defconst cwarn-font-lock-assignment-keywords
'((cwarn-font-lock-match-assignment-in-expression
(1 font-lock-warning-face))))
(defun cwarn-font-lock-match-assignment-in-expression (limit)
"Match assignments inside expressions."
(cwarn-font-lock-match
"[^!<>=]\\(\\([-+*/%&^|]\\|<<\\|>>\\)?=\\)[^=]"
(backward-up-list 1)
(and (memq (following-char) '(?\( ?\[))
(not (progn
(skip-chars-backward " ")
(skip-chars-backward "a-zA-Z0-9_")
(or
(c-at-toplevel-p)
(looking-at "for\\>")))))))
(defconst cwarn-font-lock-semicolon-keywords
'((cwarn-font-lock-match-dangerous-semicolon (0 font-lock-warning-face))))
(defun cwarn-font-lock-match-dangerous-semicolon (limit)
"Match semicolons directly after `for', `while', and `if'.
The semicolon after a `do { ... } while (x);' construction is not matched."
(cwarn-font-lock-match
";"
(backward-sexp 2) (or (looking-at "\\(for\\|if\\)\\>")
(and (looking-at "while\\>")
(condition-case nil
(progn
(backward-sexp 2) (not (looking-at "do\\>")))
(error t))))))
(defconst cwarn-font-lock-reference-keywords
'((cwarn-font-lock-match-reference (1 font-lock-warning-face))))
(defun cwarn-font-lock-match-reference (limit)
"Font-lock matcher for C++ reference parameters."
(cwarn-font-lock-match
"[^&]\\(&\\)[^&=]"
(backward-up-list 1)
(and (eq (following-char) ?\()
(not (cwarn-inside-macro))
(c-at-toplevel-p))))
(defun turn-on-cwarn-mode-if-enabled ()
"Turn on CWarn mode in the current buffer if applicable.
The mode is turned if some feature is enabled for the current
`major-mode' in `cwarn-configuration'."
(if (cwarn-is-enabled major-mode) (turn-on-cwarn-mode)))
(define-globalized-minor-mode global-cwarn-mode
cwarn-mode turn-on-cwarn-mode-if-enabled)
(provide 'cwarn)
(run-hooks 'cwarn-load-hook)