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Detect existing key binding before creating one

2

A plugin I've recently started maintaining currently checks to see if any bindings exist to its functions before creating the default ones. This makes it easy to setup custom bindings and not have to do anything about the default ones.

if !hasmapto('<Plug>MyFunction', 'n')

    nmap <buffer> <Leader>f <Plug>MyFunction

endif

What this doesn't do is keep these default bindings from clobbering existing mappings. How can I detect if, say, there is an existing normal mode mapping for <leader>f before clobbering it with the plugin's default mapping.

key-bindings vimscript leader

share|improve this question

edited 19 hours ago

Caleb

asked 20 hours ago

CalebCaleb

96211125

• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  Related question (from the opposite end of the stick): How can I prevent plugins from overwriting my key mappings?
  
  – Caleb
  19 hours ago
  

  
  
  
  

add a comment | 

2

A plugin I've recently started maintaining currently checks to see if any bindings exist to its functions before creating the default ones. This makes it easy to setup custom bindings and not have to do anything about the default ones.

if !hasmapto('<Plug>MyFunction', 'n')

    nmap <buffer> <Leader>f <Plug>MyFunction

endif

What this doesn't do is keep these default bindings from clobbering existing mappings. How can I detect if, say, there is an existing normal mode mapping for <leader>f before clobbering it with the plugin's default mapping.

key-bindings vimscript leader

share|improve this question

edited 19 hours ago

Caleb

asked 20 hours ago

CalebCaleb

96211125

• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  Related question (from the opposite end of the stick): How can I prevent plugins from overwriting my key mappings?
  
  – Caleb
  19 hours ago
  

  
  
  
  

add a comment | 

A plugin I've recently started maintaining currently checks to see if any bindings exist to its functions before creating the default ones. This makes it easy to setup custom bindings and not have to do anything about the default ones.

if !hasmapto('<Plug>MyFunction', 'n')

    nmap <buffer> <Leader>f <Plug>MyFunction

endif

What this doesn't do is keep these default bindings from clobbering existing mappings. How can I detect if, say, there is an existing normal mode mapping for <leader>f before clobbering it with the plugin's default mapping.

key-bindings vimscript leader

share|improve this question

edited 19 hours ago

Caleb

asked 20 hours ago

CalebCaleb

96211125

if !hasmapto('<Plug>MyFunction', 'n')

    nmap <buffer> <Leader>f <Plug>MyFunction

endif

share|improve this question

edited 19 hours ago

Caleb

asked 20 hours ago

CalebCaleb

96211125

share|improve this question

edited 19 hours ago

Caleb

asked 20 hours ago

CalebCaleb

96211125

asked 20 hours ago

CalebCaleb

96211125

asked 20 hours ago

CalebCaleb

96211125

2 Answers
2

active

oldest

votes

3

You can use the mapcheck() function to check if the user mapped a key to something:

:echo json_encode(mapcheck('<F1>', 'n'))

""



:echo mapcheck('<F11>', 'n')

:set cursorcolumn!<CR>:set cursorcolumn?<CR>

So in your mapping, you can do:

if !hasmapto('<Plug>MyFunction', 'n') && mapcheck('<Leader>f', 'n') is# ''

    nmap <buffer> <Leader>f <Plug>MyFunction

endif

---

Personally, I'm not completely convinced this is actually a good approach though. While it does prevent overriding user mappings, it's also very "magic" and may be surprising.

An approach that I often use is to make a single setting to disable all mappings:

if get(g:, 'myplugin_map_keys', 1)

    nmap <buffer> <Leader>f <Plug>MyFunction

endif

This way users have a reasonable set of mappings by default, but can disable mappings and do their own thing if they want something custom.

Another option is to map from a variable:

exe printf('nmap <buffer> %s <Plug>MyFunction',

          get(g:, 'myplugin_map_foo', '<Leader>f')

This way users can set their own keys for a specific mapping, without having to remap everything.

---

I don't think there is "one right way". Aside from personal preference, it also depends on the kind of plugin you're working on. For some plugins a key mapping is just an "extra bonus", whereas it's critical for others. Some plugins map just one or two keys, others dozens or even hundreds.

For smaller plugins with just one or two mappings, the first method will usually be better; for larger plugins with a lot of mappings, the second is often better. Of course, you can also do both.

share|improve this answer

answered 19 hours ago

Martin Tournoij♦Martin Tournoij

35.9k14111185

• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  Thanks. Using this I searched around for other implementations and am now wondering why you used ... is# '' instead of ... == ''. Can you clarify that bit?
  
  – Caleb
  19 hours ago
  
  
  

  
  
  
  


• 
  
  
  

  
  2
  

  
  
  
  
  
  

  
  
  @Caleb is is the "strict comparison", similar to === in JavaScript and PHP. 0 == '' is 1, which is often not what you want, but 0 is '' is 0. The # is to explicitly match case (otherwise ignorecase setting is used). Neither are strictly needed here, but it's just a habit I've picked up after I ran in to a few bugs with ==, and I think everyone should probably be using it (just like everyone is using ===). Also see :help expr4.
  
  – Martin Tournoij♦
  19 hours ago
  
  
  

  
  
  
  

add a comment | 

1

silent! {map} <unique> {lhs} {rhs}

Works too. The <unique> modifier issues an error if there is already a mapping for the left-hand side, which silent swallows.

share|improve this answer

answered 13 hours ago

D. Ben KnobleD. Ben Knoble

2,4381520

add a comment | 

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3

You can use the mapcheck() function to check if the user mapped a key to something:

:echo json_encode(mapcheck('<F1>', 'n'))

""



:echo mapcheck('<F11>', 'n')

:set cursorcolumn!<CR>:set cursorcolumn?<CR>

So in your mapping, you can do:

if !hasmapto('<Plug>MyFunction', 'n') && mapcheck('<Leader>f', 'n') is# ''

    nmap <buffer> <Leader>f <Plug>MyFunction

endif

---

Personally, I'm not completely convinced this is actually a good approach though. While it does prevent overriding user mappings, it's also very "magic" and may be surprising.

An approach that I often use is to make a single setting to disable all mappings:

if get(g:, 'myplugin_map_keys', 1)

    nmap <buffer> <Leader>f <Plug>MyFunction

endif

This way users have a reasonable set of mappings by default, but can disable mappings and do their own thing if they want something custom.

Another option is to map from a variable:

exe printf('nmap <buffer> %s <Plug>MyFunction',

          get(g:, 'myplugin_map_foo', '<Leader>f')

This way users can set their own keys for a specific mapping, without having to remap everything.

---

I don't think there is "one right way". Aside from personal preference, it also depends on the kind of plugin you're working on. For some plugins a key mapping is just an "extra bonus", whereas it's critical for others. Some plugins map just one or two keys, others dozens or even hundreds.

For smaller plugins with just one or two mappings, the first method will usually be better; for larger plugins with a lot of mappings, the second is often better. Of course, you can also do both.

share|improve this answer

answered 19 hours ago

Martin Tournoij♦Martin Tournoij

35.9k14111185

• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  Thanks. Using this I searched around for other implementations and am now wondering why you used ... is# '' instead of ... == ''. Can you clarify that bit?
  
  – Caleb
  19 hours ago
  
  
  

  
  
  
  


• 
  
  
  

  
  2
  

  
  
  
  
  
  

  
  
  @Caleb is is the "strict comparison", similar to === in JavaScript and PHP. 0 == '' is 1, which is often not what you want, but 0 is '' is 0. The # is to explicitly match case (otherwise ignorecase setting is used). Neither are strictly needed here, but it's just a habit I've picked up after I ran in to a few bugs with ==, and I think everyone should probably be using it (just like everyone is using ===). Also see :help expr4.
  
  – Martin Tournoij♦
  19 hours ago
  
  
  

  
  
  
  

add a comment | 

3

You can use the mapcheck() function to check if the user mapped a key to something:

:echo json_encode(mapcheck('<F1>', 'n'))

""



:echo mapcheck('<F11>', 'n')

:set cursorcolumn!<CR>:set cursorcolumn?<CR>

So in your mapping, you can do:

if !hasmapto('<Plug>MyFunction', 'n') && mapcheck('<Leader>f', 'n') is# ''

    nmap <buffer> <Leader>f <Plug>MyFunction

endif

---

Personally, I'm not completely convinced this is actually a good approach though. While it does prevent overriding user mappings, it's also very "magic" and may be surprising.

An approach that I often use is to make a single setting to disable all mappings:

if get(g:, 'myplugin_map_keys', 1)

    nmap <buffer> <Leader>f <Plug>MyFunction

endif

This way users have a reasonable set of mappings by default, but can disable mappings and do their own thing if they want something custom.

Another option is to map from a variable:

exe printf('nmap <buffer> %s <Plug>MyFunction',

          get(g:, 'myplugin_map_foo', '<Leader>f')

This way users can set their own keys for a specific mapping, without having to remap everything.

---

I don't think there is "one right way". Aside from personal preference, it also depends on the kind of plugin you're working on. For some plugins a key mapping is just an "extra bonus", whereas it's critical for others. Some plugins map just one or two keys, others dozens or even hundreds.

For smaller plugins with just one or two mappings, the first method will usually be better; for larger plugins with a lot of mappings, the second is often better. Of course, you can also do both.

share|improve this answer

answered 19 hours ago

Martin Tournoij♦Martin Tournoij

35.9k14111185

• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  Thanks. Using this I searched around for other implementations and am now wondering why you used ... is# '' instead of ... == ''. Can you clarify that bit?
  
  – Caleb
  19 hours ago
  
  
  

  
  
  
  


• 
  
  
  

  
  2
  

  
  
  
  
  
  

  
  
  @Caleb is is the "strict comparison", similar to === in JavaScript and PHP. 0 == '' is 1, which is often not what you want, but 0 is '' is 0. The # is to explicitly match case (otherwise ignorecase setting is used). Neither are strictly needed here, but it's just a habit I've picked up after I ran in to a few bugs with ==, and I think everyone should probably be using it (just like everyone is using ===). Also see :help expr4.
  
  – Martin Tournoij♦
  19 hours ago
  
  
  

  
  
  
  

add a comment | 

You can use the mapcheck() function to check if the user mapped a key to something:

:echo json_encode(mapcheck('<F1>', 'n'))

""



:echo mapcheck('<F11>', 'n')

:set cursorcolumn!<CR>:set cursorcolumn?<CR>

So in your mapping, you can do:

if !hasmapto('<Plug>MyFunction', 'n') && mapcheck('<Leader>f', 'n') is# ''

    nmap <buffer> <Leader>f <Plug>MyFunction

endif

---

Personally, I'm not completely convinced this is actually a good approach though. While it does prevent overriding user mappings, it's also very "magic" and may be surprising.

An approach that I often use is to make a single setting to disable all mappings:

if get(g:, 'myplugin_map_keys', 1)

    nmap <buffer> <Leader>f <Plug>MyFunction

endif

This way users have a reasonable set of mappings by default, but can disable mappings and do their own thing if they want something custom.

Another option is to map from a variable:

exe printf('nmap <buffer> %s <Plug>MyFunction',

          get(g:, 'myplugin_map_foo', '<Leader>f')

This way users can set their own keys for a specific mapping, without having to remap everything.

---

I don't think there is "one right way". Aside from personal preference, it also depends on the kind of plugin you're working on. For some plugins a key mapping is just an "extra bonus", whereas it's critical for others. Some plugins map just one or two keys, others dozens or even hundreds.

For smaller plugins with just one or two mappings, the first method will usually be better; for larger plugins with a lot of mappings, the second is often better. Of course, you can also do both.

share|improve this answer

answered 19 hours ago

Martin Tournoij♦Martin Tournoij

35.9k14111185

:echo json_encode(mapcheck('<F1>', 'n'))

""



:echo mapcheck('<F11>', 'n')

:set cursorcolumn!<CR>:set cursorcolumn?<CR>

if !hasmapto('<Plug>MyFunction', 'n') && mapcheck('<Leader>f', 'n') is# ''

    nmap <buffer> <Leader>f <Plug>MyFunction

endif

if get(g:, 'myplugin_map_keys', 1)

    nmap <buffer> <Leader>f <Plug>MyFunction

endif

exe printf('nmap <buffer> %s <Plug>MyFunction',

          get(g:, 'myplugin_map_foo', '<Leader>f')

share|improve this answer

answered 19 hours ago

Martin Tournoij♦Martin Tournoij

35.9k14111185

answered 19 hours ago

Martin Tournoij♦Martin Tournoij

35.9k14111185

answered 19 hours ago

Martin Tournoij♦Martin Tournoij

35.9k14111185

1

silent! {map} <unique> {lhs} {rhs}

Works too. The <unique> modifier issues an error if there is already a mapping for the left-hand side, which silent swallows.

share|improve this answer

answered 13 hours ago

D. Ben KnobleD. Ben Knoble

2,4381520

add a comment | 

1

silent! {map} <unique> {lhs} {rhs}

Works too. The <unique> modifier issues an error if there is already a mapping for the left-hand side, which silent swallows.

share|improve this answer

answered 13 hours ago

D. Ben KnobleD. Ben Knoble

2,4381520

add a comment | 

silent! {map} <unique> {lhs} {rhs}

Works too. The <unique> modifier issues an error if there is already a mapping for the left-hand side, which silent swallows.

share|improve this answer

answered 13 hours ago

D. Ben KnobleD. Ben Knoble

2,4381520

silent! {map} <unique> {lhs} {rhs}

share|improve this answer

answered 13 hours ago

D. Ben KnobleD. Ben Knoble

2,4381520

answered 13 hours ago

D. Ben KnobleD. Ben Knoble

2,4381520

answered 13 hours ago

D. Ben KnobleD. Ben Knoble

2,4381520