Nikolay Pavlov wrote:
> 2017-05-27 18:02 GMT+03:00 Brett Stahlman <brettstahl...@gmail.com>:
> > On Sat, May 27, 2017 at 8:35 AM, Nikolay Aleksandrovich Pavlov
> > <zyx....@gmail.com> wrote:
> >> 2017-05-27 12:45 GMT+03:00 Bram Moolenaar <b...@moolenaar.net>:
> >>>
> >>> Nikolay Pavlov wrote:
> >>>
> >>>> 2017-05-26 20:43 GMT+03:00 Bram Moolenaar <b...@moolenaar.net>:
> >>>> >
> >>>> > Brett Stahlman wrote:
> >>>> >
> >>>> >> >> On Tuesday, May 23, 2017 at 8:25:33 AM UTC-5, Brett Stahlman wrote:
> >>>> >> >> > On Tue, May 23, 2017 at 4:35 AM, Bram Moolenaar
> >>>> >> >> > <b...@moolenaar.net> wrote:
> >>>> >> >> > >
> >>>> >> >> > > Brett Stahlman wrote:
> >>>> >> >> > >
> >>>> >> >> %--snip--%
> >>>> >> >> > >
> >>>> >> >> > > The best solution is probably to also add the raw rhs, with
> >>>> >> >> > > the terminal
> >>>> >> >> > > codes replaced. This won't work when changing the terminal
> >>>> >> >> > > type, but
> >>>> >> >> > > that is very unlikely to happen.
> >>>> >> >> >
> >>>> >> >> > You mean adding a key such as "raw_rhs" to the dictionary
> >>>> >> >> > returned by
> >>>> >> >> > maparg()? If so, then yes this would help, but there would still
> >>>> >> >> > need to
> >>>> >> >> > be a way to determine lhs, which is currently even more
> >>>> >> >> > ambiguous than
> >>>> >> >> > rhs. While it's true that I probably already have lhs if I'm
> >>>> >> >> > calling
> >>>> >> >> > maparg(), I need a way to determine which lhs(s) is/are
> >>>> >> >> > ambiguous with a
> >>>> >> >> > given lhs. Mapcheck() gives me only the rhs of the conflicting
> >>>> >> >> > map. To
> >>>> >> >> > save and restore, I'd need to know the lhs in canonical form as
> >>>> >> >> > well.
> >>>> >> >>
> >>>> >> >> Perhaps mapcheck() could take an optional arg requesting something
> >>>> >> >> more than a simple boolean return. When called with this extra
> >>>> >> >> arg, mapcheck() could return a conflicting/ambiguous lhs (or list
> >>>> >> >> thereof) in some canonical format (possibly determined by the
> >>>> >> >> value of the extra arg itself). As long as the format returned
> >>>> >> >> could be fed to maparg(), it would be possible to find conflicting
> >>>> >> >> mappings, remove them temporarily, and subsequently restore them...
> >>>> >> >
> >>>> >> > If you define a mapping you will want to know whether the mapping
> >>>> >> > already exists and needs to be restored. For that you can use
> >>>> >> > maparg(),
> >>>> >> > no need to use mapcheck().
> >>>> >> >
> >>>> >> > Not sure why you would want to remove "conflicting" mappings.
> >>>> >> > Perhaps
> >>>> >> > when you map the ; key, and the user has ;x mapped? Then you would
> >>>> >> > need
> >>>> >> > a list. Adding a maplist() function would be better than adding
> >>>> >> > arguments to mapcheck().
> >>>> >>
> >>>> >> Yes. Very much like that. I'm implementing a sort of transient mode,
> >>>> >> in
> >>>> >> which I'll "shadow" existing maps with very short (generally single
> >>>> >> character) mappings, which are expected to be ambiguous/conflicting
> >>>> >> with
> >>>> >> existing maps, and even builtin operators. Of course, when I exit the
> >>>> >> transient mode, I'd need to restore the mappings that were shadowed.
> >>>> >>
> >>>> >> The global and builtin maps are not a problem, since the transient
> >>>> >> maps use
> >>>> >> <buffer> and <nowait>; however, without parsing the output of one of
> >>>> >> the :map
> >>>> >> functions, I have no way of knowing which buf-local mappings will be
> >>>> >> ambiguous
> >>>> >> with the transient maps I'm defining. And parsing the :map output is
> >>>> >> problematic for the reasons already mentioned: e.g., no way to tell
> >>>> >> the
> >>>> >> difference between function key <F8> and the corresponding 4
> >>>> >> characters. I'd
> >>>> >> actually considered taking some sort of iterative approach: e.g.,
> >>>> >> trying all
> >>>> >> possible permutations of lhs as input to maparg() and testing the
> >>>> >> results, in
> >>>> >> an attempt to deduce the canonical form, but this would be extremely
> >>>> >> messy,
> >>>> >> and I don't even know whether it would be deterministic... The
> >>>> >> maplist()
> >>>> >> function you mentioned, if it returned all ambiguous left hand sides
> >>>> >> in
> >>>> >> canonical form, or even a list of the corresponding maparg()-style
> >>>> >> dictionaries, would be perfect. Of course, there would also need to
> >>>> >> be a way
> >>>> >> to get the rhs's canonical form: e.g., the extra "raw_rhs" key in the
> >>>> >> maparg()
> >>>> >> or maplist() dictionary.
> >>>> >
> >>>> > OK, so for this you would use maplist() to get the list of mappings to
> >>>> > disable, use maparg() to get the current mapping, clear the mapping, do
> >>>> > your stuff, then restore the cleared mappings. You then need to make
> >>>> > sure you restore the mappings exactly as they were, even when your
> >>>> > "stuff" fails miserably.
> >>>> >
> >>>> > It's a lot easier if we would have a way to temporarily disable
> >>>> > mappings. It's mostly the same as above, but you won't need to use
> >>>> > maparg() to get the current mapping and the restore operation. Instead
> >>>> > you would disable instead of clear, and later re-enable instead of
> >>>> > restore. Still need to make sure the re-enbling does happen, no change
> >>>> > in that part.
> >>>>
> >>>> Not sure I understood what exactly you suggest to disable/restore. All
> >>>> mappings at once with one command? I would actually disagree here: I
> >>>> need something similar for translit3, but it only remaps
> >>>> single-character mappings, leaving most of other user mappings alone.
> >>>> One mapping at a time? It would be good, but given that request is
> >>>> temporary remapping naming the functionality enable/disable looks
> >>>> strange. And there are still issues with determining {lhs}.
> >>>
> >>> Let's use an example: Suppose a plugin has a special mode for entering
> >>> data (e.g. chemical formulas). It would then map some keys, e.g. "a".
> >>> If the user already has a mapping for "a" it needs to be restored when
> >>> leaving the special mode. If the user has mappings starting with "a" we
> >>> would like to disable those, to avoid the timeout waiting for the next
> >>> character.
> >>>
> >>> We do not want to disable mappings that don't interfere, to maximise the
> >>> freedom for the user to use other mappings at the same time.
> >>>
> >>>> One of the logical variants would be `:map <push> {lhs}
> >>>> {new-rhs}`/`:unmap <push> {lhs}`+`:map <pop> {lhs}`, but this is hard
> >>>> to implement and is rather limited, though less limited then
> >>>> enable/disable everything variant.
> >>>
> >>> This quickly gets complicated if we need to take into account all the
> >>> possible modes a mapping can be used in.
> >>>
> >>>> I would instead suggest a function mappings_dump()/mappings_add():
> >>>> first is similar to `nvim[_buf]_get_keymap` and should dump all
> >>>> mappings as a list of maparg()-like dictionaries. Second should define
> >>>> mappings being given a list of them. Of course, this means that
> >>>> dictionaries need to be fixed to allow correctly saving/restoring.
> >>>>
> >>>> The advantages:
> >>>>
> >>>> 1. Easier to implement. Code for creating a maparg() dictionary is
> >>>> already there, iterating over all mappings is not a problem. Results
> >>>> needs to be incompatible with maparg() or use additional keys though:
> >>>> e.g. Neovim altered the contents of `noremap` and `buffer` keys: first
> >>>> is now 0, 1 or 2 (you can’t correctly restore a mapping if you can’t
> >>>> distinguish `map <script>` and `noremap`) and second is a buffer
> >>>> number or zero.
> >>>> 2. More flexible: you can save and restore everything, push or pop
> >>>> individual mappings, create a temporary mapping which is just like
> >>>> mapping X, but has `<Plug>(Translit3TemporaryMap)` lhs instead (to be
> >>>> returned from `<expr>` mappings in order to select either plugin
> >>>> behaviour or fall back to previously present user mapping instead).
> >>>>
> >>>> I can imagine other usages enable/disable or push/pop could not
> >>>> achieve: generating configuration with mappings like :mkvimrc, but
> >>>> allows doing adjustments (parsing `:mkvimrc` output is not fun,
> >>>> especially if you want to be forward compatible), creating a plugin
> >>>> which analyses how often different mappings are used (need to copy all
> >>>> mappings to temporary then replace existing mappings with plugin
> >>>> ones).
> >>>> 3. This is also forward compatible: just need to state in the
> >>>> documentation that new significant keys may be added in the future to
> >>>> the dictionaries so they should be preserved.
> >>>
> >>> I don't see much use for this. I can't think of a practical example how
> >>> a plugin manipulates mappings it didn't create itself or even knows what
> >>> they are for.
> >>
> >> Still Vim has :mkvimrc which does manipulate (dump) mappings from
> >> third-party plugins. Also I need this functionality for some <expr>
> >> mappings: if some condition is true (e.g. `>` is preceded by `-` (C,
> >> completion) or transliteration mode was enabled, or transliteration
> >> mode is enabled *and* character that does not start a new
> >> transliteration sequence is a continuation of previous one) use plugin
> >> mapping. If it is false, fall back to whatever was there previously,
> >> including falling back to whatever mapping was there previously.
> >>
> >> Also check https://github.com/neovim/neovim/issues/6123, this is the
> >> issue backing Neovim nvim_get_keymap() API function.
> >>
> >>>
> >>> Another complication is that mappings can be added/removed by other
> >>> mappings and by autocommands.
> >>
> >> I do not see how this complication is relevant to the discussion. I.e.
> >> I do not see how this complication should affect usage or
> >> implementation of both proposed changes.
> >>
> >>>
> >>> Disabling and re-enabling mappings is definitely more efficient than
> >>> removing and adding-back mappings.
> >>
> >> And it is also definitely both harder to implement and less flexible.
> >
> > Harder to implement, perhaps, but not necessarily less
> > flexible. Though the discussion thus far has centered mostly
> > on enable/disable functionality, there's nothing about the map
> > handle interface that limits it to this. It could support
> > query and execute functions, for instance. For cases in which
> > you wish to keep the original behavior, but need to "wrap" it
> > somehow, you could use the map handle to attach prolog/epilog
> > callback functions to a map. Presumably, such callback
> > functions (which could be either lambdas or funcrefs) would
> > accept an argument that allowed them to obtain information
> > about the original map, possibly even its exact lhs and rhs.
> > The prolog callback would be even more useful if Vim provided
> > a way (e.g., nonzero return) for it to abort the original map.
>
> Enable, disable, query, execute plus two callbacks. *Four* functions
> and two callbacks in place of just two simple functions, mostly using
> the functionality that is already there. Five if you remember about
> :mkvimrc and that somebody may want to replace that on top of new API:
> query will need a mirror function for creating a mapping then.
You are completely missing the point: those two functions don't provide
the functionality we are talking about here.
> This is going to introduce a big amount of bugs just to add the
> flexibility which is naturally available through a much simpler
> approach. Emulating everything you mention on top of current VimL
> state plus mappings_dump()/mappings_load() / (mappings_clear()*) is
> not going to make plugins considerably slower (as long as you can
> operate on lists and use `map()`/`filter()`/etc: main VimL
> optimization principle is “the less Ex commands the faster the code”)
> and I do not see any other benefits, except for “with some handles
> implementation it may be slightly easier to pinpoint third-party
> plugins’ bugs”.
>
> * Found an issue in my proposal: `:execute 'unmap'` would not be easy
> or efficient to use, so additionally need either `mappings_clear({list
> to clear})` or make `mappings_load()` unmap mappings when rhs key is
> missing.
>
> >
> > Hmm... This may be overkill, but it might even be possible to
> > support the idea of a "virtual map handle": i.e., a handle not
> > to a specific map, but to a *set* of maps matching certain
> > criteria: e.g., <buffer>, <expr>, maps matching a mode mask,
> > maps starting with specific char(s), etc... Once such a
> > virtual handle had been obtained, a single call would suffice
> > to enable/disable, or even attach callbacks to all maps in the
> > set. Of course, some operations (e.g., execute) would be
> > permitted only on non-virtual (single map) handles.
>
> And this is just mappings_dump() + filter() with my approach without
> any need to invent a new DSL to describe criterias (or not invent DSL,
> but use VimL expressions which would be just as efficient as
> filter()). If I got it right then plus some way to attach callbacks to
> “new mapping defined” event to keep “callback attached” state.
--
Westheimer's Discovery:
A couple of months in the laboratory can
frequently save a couple of hours in the library.
/// Bram Moolenaar -- b...@moolenaar.net -- http://www.Moolenaar.net \\\
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