syntax belongs to a different major mode. Examples include
@dfn{literate programming} source files that combine documentation and
snippets of source code, Yacc/Bison programs that include snippets of
-plain C code, etc. To correctly indent the embedded chunks, the major
+plain C code, etc. To correctly indent the embedded chunks, the primary
mode needs to delegate the indentation to another mode's indentation
engine (e.g., call @code{c-indent-defun} for C code or
@code{python-indent-line} for Python), while providing it with some
-context to guide the indentation. The following facilities support
-such multi-mode indentation.
+context to guide the indentation. Major modes, for their part, should
+avoid calling @code{widen} in their indentation code and obey
+@code{prog-first-column}.
@defvar prog-indentation-context
This variable, when non-@code{nil}, holds the indentation context for
the sub-mode's indentation engine provided by the superior major mode.
-The value should be a list of the form @code{(@var{first-column}
-@w{(@var{start} . @var{end})} @code{prev-chunk})}. The members of the
-list have the following meaning:
+The value should be a list of the form @code{(@var{first-column} . @var{rest}}.
+The members of the list have the following meaning:
@table @var
@item first-column
The column to be used for top-level constructs. This replaces the
default value of the top-level column used by the sub-mode, usually
zero.
-@item start
-@itemx end
-The region of the code chunk to be indented by the sub-mode. The
-value of @var{end} can be @code{nil}, which stands for the value of
-@code{point-max}.
-@item prev-chunk
-If this is non-@code{nil}, it should provide the sub-mode's
-indentation engine with a virtual context of the code chunk. Valid
-values include:
-
-@itemize @minus
-@item
-A string whose contents is the text the sub-mode's indentation engine
-should consider to precede the code chunk. The sub-mode's indentation
-engine can add text properties to that string, to be reused in
-repeated calls with the same string, thus using it as a cache. An
-example where this is useful is code chunks that need to be indented
-as function bodies, but lack the function's preamble---the string
-could then include that missing preamble.
-@item
-A function. It is expected to be called with the start position of
-the current chunk, and should return a cons cell
-@w{@code{(@var{prev-start} . @var{prev-end})}} that specifies the
-region of the previous code chunk, or @code{nil} if there is no previous
-chunk. This is useful in literate-programming sources, where code is
-split into chunks, and correct indentation needs to access previous
-chunks.
-@end itemize
+@item rest
+This value is currently unused.
@end table
@end defvar
-The following convenience functions should be used by major mode's
+The following convenience function should be used by major mode's
indentation engine in support of invocations as sub-modes of another
major mode.
When no superior mode is in effect, this function returns zero.
@end defun
-@defun prog-widen
-Call this function instead of @code{widen} to remove any restrictions
-imposed by the mode's indentation engine and restore the restrictions
-recorded in @code{prog-indentation-context}. This prevents the
-indentation engine of a sub-mode from inadvertently operating on text
-outside of the chunk it was supposed to indent, and preserves the
-restriction imposed by the superior mode. When no superior mode is in
-effect, this function just calls @code{widen}.
-@end defun
-
@node Region Indent
@subsection Indenting an Entire Region
programming languages in the same buffer, like literate programming
environments or ANTLR programs with embedded Python code.
-A major mode can provide indentation context for a sub-mode through
-the 'prog-indentation-context' variable. To support this, modes that
-provide indentation should use 'prog-widen' instead of 'widen' and
-'prog-first-column' instead of a literal zero. See the node
-"(elisp) Mode-Specific Indent" in the ELisp manual for more details.
+A major mode can provide indentation context for a sub-mode. To
+support this, modes should use 'prog-first-column' instead of a
+literal zero and never call 'widen' in their indentation functions.
+See the node "(elisp) Mode-Specific Indent" in the ELisp manual for
+more details.
** ERC
it specially (since those functions are used for tabbing); in
that case, indent by aligning to the previous non-blank line."
(interactive)
+ (save-restriction
+ (widen)
(syntax-propertize (line-end-position))
(if (memq indent-line-function
'(indent-relative indent-relative-maybe))
(indent-line-to column)
(save-excursion (indent-line-to column))))
;; The normal case.
- (funcall indent-line-function)))
+ (funcall indent-line-function))))
(defun indent--default-inside-comment ()
(unless (or (> (current-column) (current-indentation))
(indent--default-inside-comment)
(when (or (<= (current-column) (current-indentation))
(not (eq tab-always-indent 'complete)))
- (funcall (default-value 'indent-line-function))))
+ (save-restriction
+ (widen)
+ (funcall (default-value 'indent-line-function)))))
(cond
;; If the text was already indented right, try completion.
(forward-line 1)))))
;; Use indent-region-function is available.
(indent-region-function
- (funcall indent-region-function start end))
+ (save-restriction
+ (widen)
+ (funcall indent-region-function start end)))
;; Else, use a default implementation that calls indent-line-function on
;; each line.
(t (indent-region-line-by-line start end)))
There are languages where part of the code is actually written in
a sub language, e.g., a Yacc/Bison or ANTLR grammar also consists
-of plain C code. This variable enables the major mode of the
+of plain C code. This variable enables the primary mode of the
main language to use the indentation engine of the sub-mode for
lines in code chunks written in the sub-mode's language.
The non-nil value should be a list of the form:
- (FIRST-COLUMN (START . END) PREVIOUS-CHUNKS)
+ (FIRST-COLUMN . REST)
FIRST-COLUMN is the column the indentation engine of the sub-mode
should use for top-level language constructs inside the code
chunk (instead of 0).
-START and END specify the region of the code chunk. END can be
-nil, which stands for the value of `point-max'. The function
-`prog-widen' uses this to restore restrictions imposed by the
-sub-mode's indentation engine.
-
-PREVIOUS-CHUNKS, if non-nil, provides the indentation engine of
-the sub-mode with the virtual context of the code chunk. Valid
-values are:
-
- - A string containing text which the indentation engine can
- consider as standing in front of the code chunk. To cache the
- string's calculated syntactic information for repeated calls
- with the same string, the sub-mode can add text-properties to
- the string.
-
- A typical use case is for grammars with code chunks which are
- to be indented like function bodies -- the string would contain
- the corresponding function preamble.
-
- - A function, to be called with the start position of the current
- chunk. It should return either the region of the previous chunk
- as (PREV-START . PREV-END), or nil if there is no previous chunk.
-
- A typical use case are literate programming sources -- the
- function would successively return the previous code chunks.")
+REST is currently unused.")
(defun prog-indent-sexp (&optional defun)
"Indent the expression after point.
"Return the indentation column normally used for top-level constructs."
(or (car prog-indentation-context) 0))
-(defun prog-widen ()
- "Remove restrictions (narrowing) from current code chunk or buffer.
-This function should be used instead of `widen' in any function used
-by the indentation engine to make it respect the value of
-`prog-indentation-context'.
-
-This function (like `widen') is useful inside a
-`save-restriction' to make the indentation correctly work when
-narrowing is in effect."
- (let ((chunk (cadr prog-indentation-context)))
- (if chunk
- ;; No call to `widen' is necessary here, as narrow-to-region
- ;; changes (not just narrows) the existing restrictions
- (narrow-to-region (car chunk) (or (cdr chunk) (point-max)))
- (widen))))
-
-
(defvar-local prettify-symbols-alist nil
"Alist of symbol prettifications.
Each element looks like (SYMBOL . CHARACTER), where the symbol
;;; 24.x Compat
\f
-(unless (fboundp 'prog-widen)
- (defun prog-widen ()
- (widen)))
-
(unless (fboundp 'prog-first-column)
(defun prog-first-column ()
0))
(interactive)
(save-excursion
(save-restriction
- (prog-widen)
+ (widen)
(goto-char (point-min))
(let ((block-end))
(while (and (not block-end)
:at-dedenter-block-start
- Point is on a line starting a dedenter block.
- START is the position where the dedenter block starts."
- (save-restriction
- (prog-widen)
(let ((ppss (save-excursion
(beginning-of-line)
(syntax-ppss))))
(looking-at (python-rx block-ender)))
:after-block-end)
(t :after-line))
- (point)))))))))
+ (point))))))))
(defun python-indent--calculate-indentation ()
"Internal implementation of `python-indent-calculate-indentation'.
current context or a list of integers. The latter case is only
happening for :at-dedenter-block-start context since the
possibilities can be narrowed to specific indentation points."
- (save-restriction
- (prog-widen)
(save-excursion
(pcase (python-indent-context)
(`(:no-indent . ,_) (prog-first-column)) ; usually 0
(`(,(or :inside-paren-newline-start-from-block) . ,start)
;; Add two indentation levels to make the suite stand out.
(goto-char start)
- (+ (current-indentation) (* python-indent-offset 2)))))))
+ (+ (current-indentation) (* python-indent-offset 2))))))
(defun python-indent--calculate-levels (indentation)
"Calculate levels list given INDENTATION.
This function can be used as the value of `add-log-current-defun-function'
since it returns nil if point is not inside a defun."
(save-restriction
- (prog-widen)
+ (widen)
(save-excursion
(end-of-line 1)
(let ((names)
"Message the first line of the block the current statement closes."
(let ((point (python-info-dedenter-opening-block-position)))
(when point
- (save-restriction
- (prog-widen)
(message "Closes %s" (save-excursion
(goto-char point)
(buffer-substring
- (point) (line-end-position))))))))
+ (point) (line-end-position)))))))
(defun python-info-dedenter-statement-p ()
"Return point if current statement is a dedenter.
"Return non-nil if current line ends with backslash.
With optional argument LINE-NUMBER, check that line instead."
(save-excursion
- (save-restriction
- (prog-widen)
(when line-number
(python-util-goto-line line-number))
(while (and (not (eobp))
(not (equal (char-before (point)) ?\\)))
(forward-line 1))
(when (equal (char-before) ?\\)
- (point-marker)))))
+ (point-marker))))
(defun python-info-beginning-of-backslash (&optional line-number)
"Return the point where the backslashed line start.
Optional argument LINE-NUMBER forces the line number to check against."
(save-excursion
- (save-restriction
- (prog-widen)
(when line-number
(python-util-goto-line line-number))
(when (python-info-line-ends-backslash-p)
(python-syntax-context 'paren))
(forward-line -1))
(back-to-indentation)
- (point-marker)))))
+ (point-marker))))
(defun python-info-continuation-line-p ()
"Check if current line is continuation of another.
When current line is continuation of another return the point
where the continued line ends."
(save-excursion
- (save-restriction
- (prog-widen)
(let* ((context-type (progn
(back-to-indentation)
(python-syntax-context-type)))
(python-util-forward-comment -1)
(when (and (equal (1- line-start) (line-number-at-pos))
(python-info-line-ends-backslash-p))
- (point-marker))))))))
+ (point-marker)))))))
(defun python-info-block-continuation-line-p ()
"Return non-nil if current line is a continuation of a block."
"\\)\\>")))
(eq (ruby-deep-indent-paren-p t) 'space)
(not (bobp)))
- (widen)
(goto-char (or begin parse-start))
(skip-syntax-forward " ")
(current-column))
((eq mhtml-tag-relative-indent 'ignore)
(setq base-indent 0)))
(narrow-to-region region-start (point-max))
- (let ((prog-indentation-context (list base-indent
- (cons (point-min) nil)
- nil)))
+ (let ((prog-indentation-context (list base-indent)))
(mhtml--with-locals submode
;; indent-line-function was rebound by
;; mhtml--with-locals.