Consolidate 'widen' calls

* lisp/progmodes/prog-mode.el (prog-indentation-context):
Un-document all elements but the first.
(prog-widen): Remove.
(http://lists.gnu.org/archive/html/emacs-devel/2017-12/msg00321.html)

* doc/lispref/text.texi (Mode-Specific Indent): Update.

* lisp/progmodes/ruby-mode.el (ruby-calculate-indent):
Don't call widen.

* lisp/progmodes/python.el
(python-indent-guess-indent-offset)
(python-info-current-defun): Replace prog-widen with widen;
these functions are not called during indentation.
(python-indent-context)
(python-indent--calculate-indentation)
(python-info-dedenter-opening-block-message)
(python-info-line-ends-backslash-p)
(python-info-beginning-of-backslash)
(python-info-continuation-line-p)
(python-info-current-defun): Remove 'widen' calls.

* lisp/indent.el (indent-according-to-mode)
(indent-for-tab-command, indent-region): Move them here.

* lisp/textmodes/mhtml-mode.el (mhtml-indent-line):
Bind prog-indentation-context to one-element list.

1 files changed, 5 insertions, 5 deletions

diff --git a/etc/NEWS b/etc/NEWS
index 4ccf468693c..eb076c943bc 100644
--- a/etc/NEWS
+++ b/etc/NEWS
@@ -1107,11 +1107,11 @@ This allows better indentation support in modes that support multiple
 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