VIM function to insert timestamp - vim

Question

Someone in a previous question suggested the following for adding timestamps to VIM:
nmap <F3> a<C-R>=strftime("%Y-%m-%d %a %I:%M %p")<CR><Esc>
imap <F3> <C-R>=strftime("%Y-%m-%d %a %I:%M %p")<CR>
Instead of using F3, I'd like to insert the timestamp by executing a function instead. For example, typing :Now.
Unfortunately, I don't grok VIM scripting. Can someone help?

Answer 1

:Now is not a function, it is a command. You can create command out of first mapping with the following code:
command -nargs=0 -bar Now execute "normal! a\<C-R>=strftime(\"%Y-%m-%d %a %I:%M %p\")\<CR>"

Answer 2

" if not has 'Last Change' in first 5 lines
fun! InsertChangeLog()
let l:flag=0
for i in range(1,5)
if getline(i) !~ '.*Last Change.*'
let l:flag = l:flag + 1
endif
endfor
if l:flag >= 5
normal(1G)
call append(0, "File: <+Description+>")
call append(1, "Created: " . strftime("%a %d/%b/%Y hs %H:%M"))
call append(2, "Last Change: " . strftime("%a %d/%b/%Y hs %H:%M"))
call append(3, "author: <+digite seu nome+>")
call append(4, "site: <+your website+>")
call append(5, "twitter: <+your twitter here+>")
normal gg
endif
endfun
" map F4 to insert change log
map <special> <F4> <esc>:call InsertChangeLog()<cr>
" update changefile log
" http://tech.groups.yahoo.com/group/vim/message/51005
" automaticaly update Last Change whitout change jump list
" see :h keepjumps
fun! LastChange()
let _s=#/
let l = line(".")
let c = col(".")
if line("$") >= 5
1,5s/\s*Last Change:\s*\zs.*/\="" . strftime("%Y %b %d %X")/ge
endif
let #/=_s
call cursor(l, c)
endfun
autocmd BufWritePre * keepjumps call LastChange()
" place holders snippets - change map !!!
" File Templates
" --------------
" <leader>j jumps to the next marker
" iabbr <buffer> for for <+i+> in <+intervalo+>:<cr><tab><+i+>
function! LoadFileTemplate()
"silent! 0r ~/.vim/templates/%:e.tmpl
syn match vimTemplateMarker "<+.\++>" containedin=ALL
hi vimTemplateMarker guifg=#67a42c guibg=#112300 gui=bold
endfunction
function! JumpToNextPlaceholder()
let old_query = getreg('/')
echo search("<+.\\++>")
exec "norm! c/+>/e\<CR>"
call setreg('/', old_query)
endfunction
autocmd BufNewFile * :call LoadFileTemplate()
nnoremap <leader>j :call JumpToNextPlaceholder()<CR>a
inoremap <leader>j <ESC>:call JumpToNextPlaceholder()<CR>a