[nvim] Add gitlens, scratchfile lua plugins

Added gitlens to show git blame for cursorline after short time. Added
makescratch plugin to create a new scratch window via simple command.

nvim/.config/nvim/lua/gitlens.lua

@@ -0,0 +1,42 @@
+local M = {}
+local api = vim.api
+
+function M.blameVirtText()
+
+  -- get the current file extension
+  local ft = vim.fn.expand('%:h:t')
+
+  if ft == '' or ft == 'bin' then -- if we are in a scratch buffer, unknown filetype, or nvim's terminal window
+    return
+  end
+
+  M.clearBlameVirtText()
+
+  local currFile = vim.fn.expand('%')
+  local line = api.nvim_win_get_cursor(0)
+  local blame = vim.fn.system(string.format('git blame -c -L %d,%d %s', line[1], line[1], currFile))
+  local hash = vim.split(blame, '%s')[1]
+  local cmd = string.format("git show %s ", hash).."--format='%an | %ar | %s'"
+
+  if hash == '00000000' then
+    text = 'Not Committed Yet'
+  else
+    text = vim.fn.system(cmd)
+    text = vim.split(text, '\n')[1]
+    if text:find("fatal") then -- if the call to git show fails
+      text = 'Not Committed Yet'
+    end
+  end
+
+  -- set virtual text for namespace 2 with the content from git and assign it to the higlight group 'GitLens'
+  api.nvim_buf_set_virtual_text(0, 2, line[1] - 1, {{ text,'GitLens' }}, {})
+
+end
+
+-- important for clearing out the text when our cursor moves
+function M.clearBlameVirtText()
+  -- clear out virtual text from namespace 2 (the namespace we will set later)
+  api.nvim_buf_clear_namespace(0, 2, 0, -1)
+end
+
+return M

nvim/.config/nvim/lua/scratchpad.lua

@@ -0,0 +1,11 @@
+local api = vim.api
+local M= {}
+
+function M.makeScratch()
+  api.nvim_command('enew')
+  -- vim.bo[0].bufhidden=hide
+  vim.bo[0].buftype=nofile
+  vim.bo[0].swapfile=false
+end
+
+return M

nvim/.config/nvim/plugin/personal/gitlens.vim

@@ -0,0 +1,23 @@
+function s:setupGitLens()
+  " -- disable gitlens unconditionally, and remove virtual text
+  lua require('gitlens').clearBlameVirtText()
+  augroup GitLens
+    autocmd!
+  augroup END
+
+  " -- if it is wanted enable gitlens on holding the cursor
+  if g:gitlens_enable
+    augroup GitLens
+      autocmd! CursorHold * lua require('gitlens').blameVirtText()
+      autocmd! CursorMoved * lua require('gitlens').clearBlameVirtText()
+      autocmd! CursorMovedI * lua require('gitlens').clearBlameVirtText()
+    augroup END
+  endif
+endfunction
+
+function s:toggleGitLens()
+  let g:gitlens_enable = !get(g:, 'gitlens_enable', 1)
+  call s:setupGitLens()
+endfunction
+
+command! GitLensToggle call s:toggleGitLens()

nvim/.config/nvim/plugin/personal/makescratch.vim

@@ -0,0 +1,5 @@
+function s:makeScratch()
+  lua require('scratchpad').makeScratch()
+endfunction
+
+command! ScratchPad call s:makeScratch()