vim: improve completion, add cmdline completion on demand

config/nvim/lua/user/plugins/completion.lua

@@ -1,77 +1,107 @@
 local config = function()
   local cmp = require('cmp')
 
-  local mapping = {
+  local map = setmetatable({
-    ['<c-n>'] = {
+    complete_or_select_next = function()
-      i = function()
+      if cmp.visible() then
-        if cmp.visible() then
+        cmp.select_next_item { behavior = cmp.SelectBehavior.Select }
-          cmp.select_next_item { behavior = cmp.SelectBehavior.Select }
+      else
-        else
+        cmp.complete()
-          cmp.complete()
+      end
-        end
+    end,
-      end,
-    },
 
-    ['<c-p>'] = {
+    complete_or_select_previous = function()
-      i = function()
+      if cmp.visible() then
-        if cmp.visible() then
+        cmp.select_prev_item { behavior = cmp.SelectBehavior.Select }
-          cmp.select_prev_item { behavior = cmp.SelectBehavior.Select }
+      else
-        else
+        cmp.complete()
-          cmp.complete()
+      end
-        end
+    end,
-      end,
-    },
 
-    ['<Down>'] = { i = cmp.mapping.select_next_item { behavior = cmp.SelectBehavior.Select } },
+    tab_completion = function(fallback)
-    ['<Up>'] = { i = cmp.mapping.select_prev_item { behavior = cmp.SelectBehavior.Select } },
+      if cmp.visible() then
+        cmp.complete_common_string()
+      elseif vim.fn.mode() == 'c' then
+        cmp.complete()
+      else
+        fallback()
+      end
+    end,
+  }, {
+    -- Make `func` available in [i]nsert and [c]mdline modes.
+    __call = function(_, func) return { i = func, c = func } end
+  })
 
-    ['<c-f>'] = { i = cmp.mapping.scroll_docs(4) },
+  local keymap = {
-    ['<c-b>'] = { i = cmp.mapping.scroll_docs(-4) },
+    ['<c-n>']     = map(map.complete_or_select_next),
+    ['<c-p>']     = map(map.complete_or_select_previous),
 
-    ['<c-e>'] = { i = cmp.mapping.abort() },
+    ['<down>']    = map(cmp.mapping.select_next_item { behavior = cmp.SelectBehavior.Select }),
-    ['<c-y>'] = { i = cmp.mapping.confirm { select = true } },
+    ['<up>']      = map(cmp.mapping.select_prev_item { behavior = cmp.SelectBehavior.Select }),
-    ['<Tab>'] = {
+
-      i = function(fallback)
+    ['<c-f>']     = map(cmp.mapping.scroll_docs(4)),
-        if cmp.visible() then
+    ['<s-down>']  = map(cmp.mapping.scroll_docs(4)),
-          cmp.confirm { select = true }
+    ['<c-b>']     = map(cmp.mapping.scroll_docs(-4)),
-        else
+    ['<s-up>']    = map(cmp.mapping.scroll_docs(-4)),
-          fallback()
+
-        end
+    ['<c-e>']     = map(cmp.mapping.abort()),
-      end,
+    ['<c-y>']     = map(cmp.mapping.confirm { select = true }),
-    },
+    ['<tab>']     = map(map.tab_completion),
   }
 
   cmp.setup {
-    mapping = mapping,
+    mapping = keymap,
+
+    snippet = {
+      expand = function(_ --[[args]])
+        -- require('luasnip').lsp_expand(args.body) TODO enable
+      end,
+    },
+
+    formatting = {
+      format = require('lspkind').cmp_format {
+        mode = 'symbol_text',
+        menu = {
+          buffer   = "[buf]",
+          nvim_lsp = "[LSP]",
+          nvim_lua = "[lua]",
+          path     = "[path]",
+        },
+      },
+    },
 
     sources = cmp.config.sources({
-      { name = 'nvim_lsp' },
       { name = 'nvim_lua' },
+      { name = 'nvim_lsp' },
+      -- { name = "luasnip" }, TODO enable
     }, {
       { name = 'path' },
       { name = 'buffer', keyword_length = 5 },
     }),
 
-    formatting = (function()
+    window = {
-      local ok, lspkind = pcall(require, 'lspkind')
+        completion = cmp.config.window.bordered(),
-      if not ok then return {} end
+        documentation = cmp.config.window.bordered(),
-      return {
+    },
-        format = lspkind.cmp_format {
-          mode = 'symbol_text',
-          menu = {
-            buffer   = "[buf]",
-            nvim_lsp = "[LSP]",
-            nvim_lua = "[lua]",
-            path     = "[path]",
-          },
-        },
-      }
-    end)(),
 
     experimental = {
       ghost_text = true,
     },
   }
+
+  cmp.setup.cmdline(':', {
+    mapping = keymap,
+
+    completion = {
+      autocomplete = false,
+    },
+
+    sources = cmp.config.sources({
+      { name = 'path' }
+    }, {
+      { name = 'cmdline' }
+    }),
+  })
 end
 
 return {
@@ -83,6 +113,7 @@ return {
     'hrsh7th/cmp-nvim-lua',
     'hrsh7th/cmp-path',
     'hrsh7th/cmp-buffer',
+    'hrsh7th/cmp-cmdline',
     'onsails/lspkind-nvim',
   },
 }