CHANGES

-*- outline -*-  

This is a summary of main changes.  For details, please see
the Git ChangeLog, the GitHub repo https://github.com/ProofGeneral/PG

* Changes of Proof General 4.6 from Proof General 4.5

N/A

* Changes of Proof General 4.5 from Proof General 4.4

** Generic changes
*** License changed to GPLv3+
*** Remove support for the following systems:
Twelf, CCC, Lego, Hol-Light, ACL2, Plastic, Lambda-Clam, Isabelle, HOL98.

*** require GNU Emacs 25.2 or later

The current policy aims at supporting multiple Emacs versions,
including those available in distributions Debian Stable
(https://packages.debian.org/stable/emacs) and Ubuntu LTS
(https://packages.ubuntu.com/emacs), until their End-Of-Support (see
also https://wiki.ubuntu.com/Releases). Support for Emacs 25 will
be dropped in April 2023 when Ubuntu Bionic reaches end of
standard support.


*** new command and menu item to easily upgrade all packages
    - To upgrade all ELPA packages (including ProofGeneral if it was
      installed via MELPA), do "M-x proof-upgrade-elpa-packages RET"
      or use the "Proof-General > Upgrade ELPA packages..." menu item

*** bug fixes
    - Using query-replace (or replace-string) in the processed region
      doesn't wrongly jump to the first match anymore.
    - cheat face (admit etc) now visible when locked.

*** remove key-binding for proof-electric-terminator-toggle
    - The default key-binding for proof-electric-terminator-toggle
      (C-c .) was too easy to enter by mistake. And it was not that
      useful as we can expect users to configure electric-terminator
      once and for all. Hence the removal of this default key-binding.

*** add another (fallback) key-binding for proof-goto-point
    - The default key-binding for proof-goto-point (C-c <C-return>)
      was not available in TTYs. Now, this function can also be run
      with "C-c RET", which happens to be automatically trigerred if
      we type "C-c <C-return>" in a TTY.

*** new proof-priority-action-list
    Similar to proof-action-list, but holding actions that need
    to go to the proof assistant at the next opportunity.

** Qrhl-tool

   Support for qrhl-tool theorem prover has been added by Dominique
   Unruh.
   References:
   - Initial pull request: https://github.com/ProofGeneral/PG/pull/636
   - Qrhl-tool web site: https://dominique-unruh.github.io/qrhl-tool

** EasyCrypt

   Support for EasyCrypt has been added.

** Coq changes

*** fix highlighting issues for ssr tactics ending with colon

    Now, { exact: term. } will always be correctly highlighted.

    However, only (forall {T: Type}, Type) will be highlighted,
    unlike term (forall { T: Type }, Type) that has a spurious space.

    Also in (forall [T: Type], Type), variable T is now highlighted.

*** new menu Coq -> Auto Compilation for all background compilation options

*** support for 8.11 vos and vok compilation

    See menu Coq -> Auto Compilation -> vos compilation, option
    coq-compile-vos and subsection "11.3.3 Quick and inconsistent
    compilation" in the Coq reference manual.

*** support for 8.5 quick compilation

    See new menu Coq -> Auto Compilation -> Quick compilation.
    Select "no quick" as long as you have not switched to "Proof
    using" to compile without -quick. Select "quick no vio2vo" to
    use -quick without vio2vo (and guess what "quick and vio2vo"
    means ;-), select "ensure vo" to ensure a sound development.
    Quick compilation is only supported for Coq < 8.11. See the
    option `coq-compile-quick' or the subsection "11.3.3 Quick
    and inconsistent compilation" in the Coq reference manual.

*** new option coq-compile-keep-going (in menu Coq -> Auto Compilation)

    Similar to ``make -k'', with this option enabled, background
    compilation does not stop at the first error but rather
    continues as far as possible.

*** Automatic insertion of "Proof using" annotations.

    PG now supports the "Suggest Proof Using" by inserting
    (automatically or by contextual menu or by a command) the "Proof
    using" annotation suggested by Coq. This suggestion happens at
    "Qed" command. By default PG will only highlight the corresponding
    "Proof" keyword and let the user actively ask for insertion. You
    can customize this behaviour by setting the
    coq-accept-proof-using-suggestion to one of these values: 'always,
    'highlight, 'ask, 'never. This is also settable from Coq menu. See
    documentation of this variable for an explanation of the different
    possible values and some more information.

*** Make ProofGeneral/Coq `opam-switch-mode' aware

    When opam-switch-mode is loaded, the Coq background process can be
    killed when changing the opam switch through opam-switch-mode, see
    `coq-kill-coq-on-opam-switch' and
    https://github.com/ProofGeneral/opam-switch-mode

*** Limited extensibility for indentation 

    Coq indentation mechanism is based on a fixed set of tokens and
    precedence rules. Extensibility is now possible by adding new
    syntax for a given token (no new token can be added). 

    Typical example: if you define a infix operator xor you may
    want to define it as a new syntax for token \/ in order to
    have the indentation rules of or applied to xor.

    Use:
    (setq coq-smie-user-tokens '(("xor" . "\\/")))
    
    The set of tokens can be seen in variable smie-grammar.

*** Indentation of monadic notations.
    Using the extensibility for indentation described above we provide
    a way to define your own monadic operators using the
    coq-smie-monadic-tokens in the same spirit as coq-smie-user-tokens
    above.

    By default two well established syntax are supported:

       x <- e ;;
       e

     and 

       do x <- e ;
       e

*** Clickable Hypothesis in goals buffer to copy/paste hyp names

    Clicking on a hyp name in goals buffer with button 2 copies its
    name at current point position (which should be in the scripting
    buffer). This eases the insertion of hypothesis names in scripts.

*** Folding/unfolding hypothesis

   A cross "-" is displayed to the left of each hypothesis of the
   goals buffer. Clicking ont it (button 1) hides/unhides the
   hypothesis. You can also hit "f" while ont he hypothesis. "F"
   unfolds all hypothesis.
   
   Hide/ unhide status remains when goal changes.

*** Highlighting of hypothesis

    You can highlight hypothesis in goals buffer on a per name
    fashion. Hit "h" while on the hypothesis. "H" removes all
    highlighting in the buffer.

    Highlighting status remains when goal changes.

**** Automatic highlighting with (search)About.
    Hypothesis cited in the response buffer after C-c C-a C-a (i.e.
    M-x coq-SearchAbout) will be highlighted automatically. Any other
    hypothesis highlighted is unhighlighted.
    
    To disable this, do:

    (setq coq-highlight-hyps-cited-in-response nil)

*** Support Coq's feature for highlighting the differences
    between successive proof steps.  See section 11.8 ("Showing
    Proof Diffs") in the documentation.

*** Support Ssreflect's proof style for inserting an intros tactic
    when doing "C-c C-a TAB": PG inserts "move=> ..." if the current
    file contains "Require ... ssreflect" on the same line; otherwise
    PG inserts "intros ..." as before.

*** Customizing Search Blacklist (command created and menu entry moved)
    To change the list of blacklisted string for Search commands
    during development, use now
    coq-change-search-blacklist-interactive. The menu for this has
    moved, it is now in Coq/Other Queries/Search Blacklist.

    To change the default blacklist, set variable
    coq-search-blacklist-string (unchanged).

*** Proof General can omit complete opaque proofs
    This speeds up asserting of larger chunks at the price of
    letting errors in these proofs go unnoticed. Configure
    `proof-omit-proofs-option' or select "Proof-General -> Quick
    Options -> Processing -> Omit Proofs". See also section
    "11.5 Omitting proofs for speed" in the manual.

    Beware that if lemmas are proved in a section, these lemmas should
    start with a "Proof using" annotation, otherwise Coq would compute
    a wrong type for them when this omitting-proofs feature is enabled.

*** bug fixes
    - avoid leaving partial files behind when compilation fails
    - 123: Parallel background compilation fails to execute some
      imports
    - fix error in process filter: Cannot resize window
    - 54 partially: Buffer coq-compile-response sometimes takes
      over the whole window
    - 75, superseded by 352: fix detection of imported libraries
      for background compilation
    - 70, 119: Coq trunk + compile before require => « Invalid version
      syntax: 'trunk' »
    - 92: Compile before require from current directory failing
      with 8.5
    - fix background compilation for the case of identical time stamps
    - improve background compilation when both .vio and .vo files
      are up-to-date
    - 33: cyclic dependencies
    - 130: parallel build of Proof General
    - Prevent non-existent directories from crashing PG
    - 143: interrupt diverting tactics
    - 142: Quick compilation mode is not saved
    - 499: emacs eats up all my RAM while processing imports
    - various compatibility fixes for various Emacs versions
    - fix Proof General manual generation
    - 551: fix Proof General when coqtop is absent
    - background compilation may break when changing current buffer
    - check for the case that coqdep does not report an error on unknown file
    - 527: ProofGeneral freezes when there is a build error in a dependency file
    - 563: Never send two commands at once
    - 537: some test in ci/coq-tests.el fails sporadically

*** indentation code refactored

    A big refactoring of the code for indentation has been done. You
    may experience a few changes in indentation results. Mostly small
    shifts to the right.

    Variable `coq-indent-box-style' only affects indentation after
    quantifiers (used to affect script braces "{").

    Variable `coq-indent-align-with-first-arg` governs between these
    two indentation behaviours:

    (setq 'coq-indent-align-with-first-arg t) gives

        somefunciton x y
                     z t u
                     v
    (setq 'coq-indent-align-with-first-arg nil) give (default):

        somefunciton x y
          z t u
          v

*** using github CI with a large test body
    Proof General uses now the continuous integration
    infrastructure at github to execute quite a number of tests
    on each pull request. The tests regularly find issues in
    Proof General, but also in Coq or Emacs.

*** various coqtags improvements

*** redesign of automatic background compilation

    The code for automatic background compilation has been
    redesigned, the internal logic simplified and big portions
    were rewritten.

* Changes of Proof General 4.4 from Proof General 4.3

** ProofGeneral has moved to GitHub!

   https://github.com/ProofGeneral/PG

   Please submit new bugs there.

** Coq changes

*** indentation of ";" tactical:
    by default the indentation is like this:
    tac1;
      tac2;
      tac3.
    do this: (setq coq-indent-semicolon-tactical 0) to have this:
    tac1;
    tac2;
    tac3.

*** Option to disable the auto resizing of response buffer:

    By default when the response buffer is on the same column than
    goals buffer, pg changes its size dynamically to optimize goals
    displaying.

    To disable this feature use:
    (setq coq-optimise-resp-windows-enable nil)
    
*** Option to prefer top of conclusion instead of bottom

    When display goals that do not fit in the goals window, PG prefers
    to display the bottom of the goal (where lies it own conclusion.
    You can make it prefer the top of the conclusion by setting this:
    (setq coq-prefer-top-of-conclusion t)

*** Auto adjusting of printing width

    On by default. To disable: Coq/Settings/Auto Adapt Printing Width
    or (setq coq-auto-adapt-printing-width nil).

*** Removed the Set Undo 500 at start.
    This is obsolete. To recover: (setq coq-user-init-cmd `("Set Undo 500."))

*** Option to highlight usual symbols
    Off by default, enable using:
    (setq coq-symbol-highlight-enable t)

* Changes of Proof General 4.3 from Proof General 4.2

** Prooftree changes

*** Require Prooftree version 0.11
    Check the Prooftree website to see which other versions of
    Prooftree are compatible with Proof General 4.3.

*** New features
    One can now trigger an retraction (undo) by selecting the
    appropriate sequent in Prooftree. One can further send proof
    commands or proof scripts from whole proof subtrees to Proof
    General, which will insert them in the current buffer.
    Prooftree also supports some recent Coq features, see below.

** Coq changes

*** Asynchronous parallel compilation of required modules
    Proof General has now a second implementation for compiling
    required Coq modules. 
    Check menu Coq -> Settings -> Compile Parallel In Background
    to compile modules in parallel in the background while Proof
    General stays responsive.

*** Support for more bullets (coq 8.5): -- --- ++ +++ ** ***
    Scripting supports bullets of any length. 
    Indentation supports only bullets of length <= 4 (like ----). Longer
    may be supported if needed.
    For indentation to work well, please use this precedence:
    - + * -- ++ ** --- +++ *** ...

*** smie indentation is now the only choice.
    Old code removed. will work only if emacs >= 23.3.

*** indentation of modules, sections and proofs are customizable

    (setq coq-indent-modulestart X) will set indentation width for
    modules and sections to X characters

    (setq coq-indent-proofstart X) will set indentation width for
    modules and sections to X characters

*** indentation of match with cases:
    by default the indentation is like this now:
    match n with
      O => ...
    | S n => ...
    end
    do this: (setq coq-match-indent 4) to get back the
    previous indetation style:
    match n with
        O => ...
      | S n => ...
    end    

*** indentation now supports { at end of line:
    example:

    assert (h:n = k). {
      apply foo.
      reflexivity. }
    apply h.

*** Default indentation of forall and exists is not boxed anymore
    For instance, this is now indented like this:

       Lemma foo: forall x y,
           x = 0 -> ... .

    instead of:

       Lemma foo: forall x y,
                    x = 0 -> ... .
    (do this: (setq coq-indent-box-style t) to bring the box style back).

    Use (setq coq-smie-after-bolp-indentation 0) for a smaller indentation:
       Lemma foo: forall x y,
         x = 0 -> ... .

*** Default indentation cases of "match with" are now indented by 2 instead of 4.
     "|" is indented by zero:

        match n with                   
          0 => ...	     
        | S n => ...                   
        end                            
     instead of: 
        match n with  
            0 => ...       
          | S n => ...
        end
     do this: (setq coq-match-indent 4) to bring old behaviour back.

*** Support for bullets, braces and Grab Existential Variables for Prooftree.

*** Support for _Coqproject files

    According to Coq documentation, it is advised to use coq_makefile
    -f _CoqProject -o Makefile to build your Makefile automatically
    from "profect file" _CoqProject. Such a file should contain the
    options to pass to coq_makefile, i.e. paths to add to coq load
    path (-I, -R) and other options to pass to coqc/coqtop (-arg).

    Coqide (and now proofgeneral) do use the information stored in
    this file to configure the options to add to the coqtop
    invocation. When opening a coq file, proofgeneral looks for a file
    _Coqproject in the current directory or a parent directory and
    reads it. Except for very unlikely situation this should replace
    the use of local file variables (which remains possible and
    overrides project file options).

*** Support for prettify-symbols-mode.

*** Colors in response and goals buffers

    Experimental: colorize hypothesis names and some parts of error
    and warning messages, and also evars. For readability.

*** Coq Querying facilities

**** Minibuffer interactive queries

    Menu Coq/Other Queries (C-c C-a C-q) allows to send queries (like
    Print, Locate...) (à la auctex) without inserting them in the
    buffer. Queries are TAB completed and the usual history mechanism
    applies. Completion allows only a set of state preserving
    commands. The list is not exhaustive yet.

    This should replace the C-c C-v usual command mechanism (which has
    no completion).

**** Mouse Queries

    This remaps standard emacs key bindings (faces and buffers menus
    popup), so this is not enabled by default, use (setq
    coq-remap-mouse-1 t) to enable.

    - (control mouse-1) on an identifier sends a Print query on that id.
    - (shift mouse-1) on an identifier sends a About query on that id.
    - (control shift mouse-1) on an identifier sends a Check query on
      that id.

    As most of the bindings, they are active in the three buffer
    (script, goals, response). Obeys C-u prefix for "Printing all"
    flag.

*** bug fixes
    - Annoying cursor jump when hitting ".".
    - random missing output due to the prover left in silent mode by
      a previously scripted error.
    - Better display of warnings (less messages lost).

* Changes of Proof General 4.2 from Proof General 4.1

** Generic/misc changes

*** Added user option: `proof-next-command-insert-space'
    Allows the user to turn off the electric behaviour of generating
    newlines or spaces in the buffer.  Turned on by default, set
    to nil to revert to PG 3.7 behaviour.

*** Support proof-tree visualization via the external Prooftree program
    Currently only Coq (using Coq version 8.4beta or newer)
    supports proof-tree visualization. If Prooftree is installed,
    the proof-tree display can be started via the toolbar, the
    Proof-General menu or by C-c C-d.  To get Prooftree, visit
    http://askra.de/software/prooftree

*** Compilation fixes for Emacs 24.

*** Fix "pgshell" mode for shell/CLI prover interaction
    Also add some quick hacks for scripting OCaml and Haskell


** Coq changes

*** Smarter three windows mode:
  In three pane mode, there are three display modes, depending
  where the three useful buffers are displayed: scripting
  buffer, goals buffer and response buffer.

  Here are the three modes:

  - vertical: the 3 buffers are displayed in one column.
  - hybrid: 2 columns mode, left column displays scripting buffer
    and right column displays the 2 others.
  - horizontal: 3 columns mode, one for each buffer (script, goals,
    response).

  By default, the display mode is automatically chosen by
  considering the current emacs frame width: if it is smaller
  than `split-width-threshold' then vertical mode is chosen,
  otherwise if it is smaller than 1.5 * `split-width-threshold'
  then hybrid mode is chosen, finally if the frame is larger than
  1.5 * `split-width-threshold' then the horizontal mode is chosen.

  You can change the value of `split-width-threshold' at your
  will (by default it is 160).

  If you want to force one of the layouts, you can set variable
  `proof-three-window-mode-policy' to 'vertical, 'horizontal or
  'hybrid. The default value is 'smart which sets the automatic
  behaviour described above.

  example:

     (setq proof-three-window-mode-policy 'hybrid).

  Or via customization menus.

*** Multiple file handling for Coq Feature.
    No more experimental. Set coq-load-path to the list of directories
    for libraries (you can attach it to the file using menu "coq prog
    args"). Many thanks to Hendrik Tews for that great peace of code!

*** Support proof-tree visualization
    Many thanks to Hendrik Tews for that too!

*** New commands for Print/Check/About/Show with "Printing All" flag
    Avoids typing "Printing All" in the buffer. See the menu Coq >
    Other queries. Thanks to Assia Mahboubi and Frederic Chyzak for
    the suggestion.
    Shortcut: add C-u before the usual shortcut
     (example: C-u C-c C-a C-c for:
     	        Set Printing All.
		Check.
		Unset Printing All. )

*** Coq menus and shortcut in response and goals buffers.
    Check, Print etc available in these buffers.

*** Tooltips hidden by default
    Flickering when hovering commands is off by default!

*** "Insert Requires" now uses completion based on coq-load-path

*** New setting for hiding additional goals from the *goals* buffer
    Coq > Settings > Hide additional subgoals

*** Double hit terminator
    Experimental: Same as electric terminator except you have to type
    "." twice quickly. Electric terminator will stop getting in the
    way all the time with module.notations.
     Coq > Double Hit Electric Terminator.

    Note 1: Mutually exclusive with usual electric terminator.

    Note 2: For french keyboard it may be convenient to map ";"
    instead of ".":

(add-hook 'proof-mode-hook
 (lambda () (define-key coq-mode-map (kbd ";") 'coq-terminator-insert)))


*** Indentation improvements using SMIE. Supporting bullets and { }.
    Still experimental. Please submit bugs.

    IMPORTANT: Limitations of indentation:

    - hard-wired precedence between bullets: - < + < *
     example:
     Proof.
       - split.
         + split.
           * auto.
	   * auto.
         + intros.
           auto.
       - auto.
     Qed.

    - Always use "Proof." when proving an "Instance" (wrong
      indentation and slow downs otherwise). As a general rule, try to
      always introduce a proof with "Proof." (or "Next Obligation"
      with Program).

*** "Show" shows the (cached) state of the proof at point.
    If Show goals (C-c C-a C-s) is performed when point is on a locked
    region, then it shows the prover state as stored by proofgeneral
    at this point. This works only when the command at point has been
    processed by "next step" (otherwise coq was silent at this point
    and nothing were cached).

*** Minor parsing fixes
*** Windows resizing fixed

** HOL Light  [WORK IN PROGRESS]

*** Basic support now works, see hol-light directory  [WORK IN PROGRESS]


* Changes of Proof General 4.1 from Proof General 4.0

** Generic changes

*** Parsing now uses cache by default (proof-use-parser-cache=t).
    Speeds up undo/redo in long buffers if no edits are made.

** Isabelle changes

*** Unicode tokens enabled by default

** Coq changes

*** A new indentation algorithm, using SMIE.
    This works when SMIE is available (Emacs >= 23.3), but must be enabled
    by the variable `coq-use-smie'.  It also provides improved
    navigation facilities for things like C-M-t, C-M-f and C-M-b.
    Addition by Stefan Monnier.

*** Experimental multiple file handling for Coq.
    Proof General is now able to automatically compile files while
    scripting Require commands, either internally or externally (by
    running Make).  Additionally, it will automatically retract 
    buffers when switching to new files, to model separate compilation
    properly.  For details, see the Coq chapter in the Proof General manual.
    Addition by Hendrik Tews.

*** Fixes for Coq 8.3


* Main Changes for Proof General 4.0 from 3.7.1

** Install/support changes

*** XEmacs is no longer supported; PG only works with GNU Emacs 23.1+
    Older GNU Emacs versions after 22.3 may work but are unsupported.

*** Primary distribution formats changed
    The RPM and zip file formats have been removed.
    We are very grateful to third-party packagers for Debian and Fedora
    for distributing packaged versions of PG.

** Generic changes

*** Font-lock based Unicode Tokens mode replaces X-Symbol
    Unicode Tokens has been significantly improved since PG 3.7.1,
    and now works purely at a "presentation" level without changing 
    buffer contents.  See Tokens menu for many useful commands.

*** Document-centred mechanisms added:
    - auto raise of prover output buffers can be disabled
    - output retained for script buffer popups
    - background colouring for locked region can be disabled
    - ...but "sticky" colouring for errors can be used
    - edit on processed region can automatically undo

    Depending on the prover language and interaction output, this may
    enable a useful "document centred" way of working, when output
    buffers can be ignored and hidden.  Use "full annotation" to keep
    output when several steps are taken.

    Standard values for the options can be set in one go with:
      Quick Options -> Display -> Document Centred
    and the defaults set back with 
      Quick Options -> Display -> Default. 
    See the manual for more details.

*** Automatic processing mode
      Quick Options -> Processing -> Send Automatically
    Sends commands to the prover when Emacs is idle for a while.
    This only sends commands when the last processing action has
    been an action moving forward through the buffer.  Interrupt by
    making a keyboard/mouse action.
    See the manual for more details.

*** Fast buffer processing option
      Quick Options -> Processing -> Fast Process Buffer
    This affects 'proof-process-buffer' (C-c C-b, toolbar down).
    It causes commands to be sent to the prover in a tight loop, without 
    updating the display or processing other input.  This speeds up
    processing dramatically on some Emacs implementations.
    To interrupt, use C-g, which reverts to normal processing mode.
    (To stop that, use C-c C-c as usual).

*** Improved prevention of Undo in locked region
    With thanks to Erik Martin-Dorel and Stefan Monnier.
    Undo in read only region follows `proof-strict-read-only' and
    gives the user the chance to allow edits by retracting first.

*** Proof General -> Options menu extended and rearranged
    - new menu for useful minor modes indicates modes that PG supports

*** New query identifier info button and command (C-c C-i, C-M-mouse1)
    These are convenience commands for looking up identifiers in the running prover.

*** New user configuration options (also on Proof General -> Options)
    proof-colour-locked       (use background colour for checked text)
    proof-auto-raise-buffers  (set to nil for manual window control)
    proof-full-decoration     (add full decoration to input text)
    proof-sticky-errors       (add highlighting for commands that caused error)
    proof-shell-quiet-errors  (non-nil to disable beep on error; default=nil)
    proof-minibuffer-messages (non-nil to show prover messages; default=nil)

*** Removed user configuration options
    proof-toolbar-use-button-enablers  (now always used)
    proof-output-fontify-enable        (now always enabled)

*** "Movie" output: export an annotated buffer in XML
    Basic movie output for Proviola, see http://mws.cs.ru.nl/proviola

** Isabelle/Isar changes

*** Support undo back into completed proofs (linear_undo).

*** Electric terminator works without inserting terminator
    Hit ; to process the last command.  Easier than C-RET.

*** Line numbers reported during script management

*** Sync problems with bad input prevented by command wrapping

*** Isabelle Settings now organised in sub-menus

** Coq changes

*** Only supports Coq 8.1+, support for earlier versions dropped.

*** Holes mode can be turned on/off and has its own minor mode

*** Some keyboard shortcuts are now available in goals buffer
    C-c C-a C-<c,p,o,b,a> are now available in goal buffer.

*** Experimental storing buffer
    To store the content of response or goals buffer in a dedicated
    persistent buffer (for later use), use Coq/Store response or
    Coq/Store goal.

*** bug fixes, bugs
    - Three panes mode: "window would be too small" error fixed.
    - Indentation: several error fixed. If you want to indent tactics
    inside "Instance" or "Add Parametric Relation" etc, please put
    "Proof." before the tactics, there is no way for emacs to guess
    whether these commands initiate new goals or not.
    - coq prog args permanent settings is working again
    - when a proof is completed, the goals buffer is cleared again.

** Notable internal changes

*** Altered prover configuration settings (internal)

    proof-terminal-char replaced by proof-terminal-string

    urgent message matching is now anchored; configurations for
    `proof-shell-clear-response-regexp', etc, must match
    strings which begin with `proof-shell-eager-annotation-start'.

    proof-shell-strip-output-markup: added for cut-and-paste
    proof-electric-terminator-noterminator: allows non-insert of terminator

    pg-insert-output-as-comment-fn: removed (use p-s-last-output)
    proof-shell-wakeup-char: removed (special chars deprecated)
    pg-use-specials-for-fontify: removed (ditto)
    proof-shell-prompt-pattern: removed (was only for shell UI)
    proof-shell-abort-goal-regexp: removed (ordinary response)
    proof-shell-error-or-interrupt-seen: removed, use p-s-last-output-kind
    proof-script-next-entity-regexps,next-entity-fn: removed (func-menu dead)
    proof-script-command-separator: removed (always a space)

*** Simplified version of comint now used for proof shell (internal)
    To improve efficiency, a cut-down version of comint is now used.
    Editing, history and decoration in the shell (*coq*, *isabelle*,
    etc) are impoverished compared with PG 3.X.