2017-05-27 19:48 GMT+03:00 Bram Moolenaar <b...@moolenaar.net>:
>
> 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.
Why do you think so? They provide everything what is needed to
implement the functionality we are talking about here in VimL.
>
>> 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 \\\
> /// sponsor Vim, vote for features -- http://www.Vim.org/sponsor/ \\\
> \\\ an exciting new programming language -- http://www.Zimbu.org ///
> \\\ help me help AIDS victims -- http://ICCF-Holland.org ///
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