Remove prog-indentation-context

* lisp/progmodes/prog-mode.el: (prog-indentation-context)
(prog-first-column, prog-widen): Remove, as discussed in
http://lists.gnu.org/archive/html/emacs-devel/2016-03/msg01425.html.

* doc/lispref/text.texi (Mode-Specific Indent): Remove references
to them.

* etc/NEWS: Ditto.

* lisp/progmodes/python.el: (prog-widen, prog-first-column):
Remove the compatibility aliases and all uses.

Do not merge to master.

1 files changed, 0 insertions, 68 deletions

diff --git a/lisp/progmodes/prog-mode.el b/lisp/progmodes/prog-mode.el
index 718b33932ed..3f25a0c0647 100644
--- a/lisp/progmodes/prog-mode.el
+++ b/lisp/progmodes/prog-mode.el
@@ -49,53 +49,6 @@
     map)
   "Keymap used for programming modes.")
 
-(defvar prog-indentation-context nil
-  "When non-nil, provides context for indenting embedded code chunks.
-
-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
-main language to use the indentation engine of the sub-mode for
-lines in code chunks written in the sub-mode's language.
-
-When a major mode of such a main language decides to delegate the
-indentation of a line/region to the indentation engine of the sub
-mode, it should bind this variable to non-nil around the call.
-
-The non-nil value should be a list of the form:
-
-   (FIRST-COLUMN (START . END) PREVIOUS-CHUNKS)
-
-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.")
-
 (defun prog-indent-sexp (&optional defun)
   "Indent the expression after point.
 When interactively called with prefix, indent the enclosing defun
@@ -109,27 +62,6 @@ instead."
 	  (end (progn (forward-sexp 1) (point))))
       (indent-region start end nil))))
 
-(defun prog-first-column ()
-  "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