Some big updates

* Use collection to denote the list of mappings
* Let default collections be defined through a function
* Allow separate leader keys for each collection
* Test for ultisnips before creating mappings

autoload/vimtex/imaps.vim

@@ -11,19 +11,50 @@ endfunction
 
 " }}}1
 function! vimtex#imaps#init_script() " {{{1
+  let s:has_ultisnips = exists('*UltiSnips#Anon')
+endfunction
+
+" }}}1
+function! vimtex#imaps#init_buffer() " {{{1
+  if !g:vimtex_imaps_enabled | return | endif
+
+  let b:vimtex.imap_collections = []
+
   "
-  " Define default lists of imaps
+  " Create predefined imaps
   "
-  let s:imaps = {
+  for collection in s:default_collections()
-        \ 'miscellaneous' : {
+    if get(g:, 'vimtex_imaps_' . collection.title, 1)
-        \   'list' : [
+      call s:parse_collection(collection)
+    endif
+  endfor
+
+  "
+  " Create custom imaps if defined
+  "
+  for collection in get(g:, 'vimtex_imaps_custom', [])
+    call s:parse_collection(collection)
+  endfor
+endfunction
+
+" }}}1
+
+function! s:default_collections() " {{{1
+  return [
+    \ {
+    \   'title' : 'miscellaneous',
+    \   'leader' : '',
+    \   'mode' : '',
+    \   'mappings' : [
     \     ['...', '\dots'],
     \     ['<m-i>', '\item '],
     \   ],
     \ },
-        \ 'math' : {
+    \ {
-        \   'math' : 1,
+    \   'title' : 'math',
-        \   'list' : [
+    \   'leader' : '',
+    \   'mode' : 'm',
+    \   'mappings' : [
     \     ['__', '_\{$1\}'],
     \     ['^^', '^\{$1\}'],
     \     ['((', '\left($1\right)'],
@@ -47,10 +78,10 @@ function! vimtex#imaps#init_script() " {{{1
     \     ['qK', '\Uparrow'],
     \   ],
     \ },
-        \ 'math_leader' : {
+    \ {
-        \   'leader' : 1,
+    \   'title' : 'math_leader',
-        \   'math' : 1,
+    \   'mode' : 'm',
-        \   'list' : [
+    \   'mappings' : [
     \     ['i', '\int_{$1}^{$2}'],
     \     ['S', '\sum_{$1}^{$2}'],
     \     ['/', '\frac{$1}{$2}'],
@@ -69,10 +100,10 @@ function! vimtex#imaps#init_script() " {{{1
     \     ['_', '\bar{$1}'],
     \   ],
     \ },
-        \ 'greek' : { 
+    \ { 
-        \   'leader' : 1,
+    \   'title' : 'greek',
-        \   'math' : 1,
+    \   'mode' : 'm',
-        \   'list' : [
+    \   'mappings' : [
     \     ['a', '\alpha'],
     \     ['b', '\beta'],
     \     ['c', '\chi'],
@@ -107,53 +138,26 @@ function! vimtex#imaps#init_script() " {{{1
     \     ['Y', '\Psi'],
     \   ],
     \ },
-        \}
+    \]
 endfunction
 
 " }}}1
-function! vimtex#imaps#init_buffer() " {{{1
+function! s:parse_collection(collection) " {{{1
-  if !g:vimtex_imaps_enabled | return | endif
+  "
+  " Extract some collection metadata
+  "
+  let l:leader = get(a:collection, 'leader', g:vimtex_imaps_leader)
+  let l:mode = get(a:collection, 'mode', '')
+  let l:math = l:mode =~# 'm'
 
   "
-  " Create predefined imaps
+  " Create mappings
   "
-  for [name, imaps] in items(s:imaps)
+  for [lhs, rhs] in a:collection.mappings
-    if get(g:, 'vimtex_imaps_' . name, 1)
-      echom 'imaps created: ' . name
-      call s:create_imaps(imaps)
-    endif
-  endfor
-
-  "
-  " Create custom imaps if defined
-  "
-  for imaps in get(g:, 'vimtex_imaps_custom', [])
-    call s:create_imaps(imaps)
-  endfor
-
-  "
-  " Escape the leader
-  "
-  silent execute 'inoremap <silent><buffer>'
-        \ g:vimtex_imaps_leader . g:vimtex_imaps_leader
-        \ g:vimtex_imaps_leader
-endfunction
-
-" }}}1
-
-"
-" Functions to create the imaps
-"
-function! s:create_imaps(imaps) " {{{1
-  let l:leader = get(a:imaps, 'leader', 0)
-  let l:math = get(a:imaps, 'math', 0)
-
-  for [lhs, rhs] in a:imaps.list
     let l:ultisnips = match(rhs, '$1') > 0
+    if l:ultisnips && !s:has_ultisnips | continue | endif
 
-    "
     " Generate RHS
-    "
     if l:math && l:ultisnips
       let rhs = s:wrap_math_ultisnips(lhs, rhs)
     elseif l:math
@@ -162,16 +166,24 @@ function! s:create_imaps(imaps) " {{{1
       let rhs = s:wrap_ultisnips(lhs, rhs)
     endif
 
-    "
+    silent execute 'inoremap <silent><buffer>' l:leader . lhs rhs
-    " Add leader
-    "
-    let lhs = l:leader ? g:vimtex_imaps_leader . lhs : lhs
-
-    silent execute 'inoremap <silent><buffer>' lhs rhs
   endfor
+
+  "
+  " Escape leader if it exists
+  "
+  if l:leader !=# '' && !hasmapto(l:leader, 'i')
+    silent execute 'inoremap <silent><buffer>' l:leader . l:leader l:leader
+  endif
+
+  let b:vimtex.imap_collections += [a:collection.title]
 endfunction
 
 " }}}1
+
+"
+" Helper functions
+"
 function! s:wrap_math_ultisnips(lhs, rhs) " {{{1
   return a:lhs . '<c-r>=<sid>is_math() ? UltiSnips#Anon('''
         \ . a:rhs . ''', ''' . a:lhs . ''', '''', ''i'') : ''''<cr>'