let g:mapping = {}
let g:mapping["a"] = "αἀἁἂἃἄἅἆἇὰάᾀᾁᾂᾃᾄᾅᾆᾇᾰᾱᾲᾳᾴᾶᾷ"
let g:mapping["b"] = "β"
let g:mapping["c"] = "ψ"
let g:mapping["d"] = "δ"
let g:mapping["e"] = "εἐἑἒἓἔἕὲέ"
let g:mapping["f"] = "φ"
let g:mapping["g"] = "γ"
let g:mapping["h"] = "ηἠἡἢἣἤἥἦἧὴήᾐᾑᾒᾓᾔᾕᾖᾗῂῃῄῆῇ"
let g:mapping["i"] = "ιἰἱἲἳἴἵἶἷὶίῐῑῒΐῖῗ"
let g:mapping["j"] = "ξ"
let g:mapping["k"] = "κ"
let g:mapping["l"] = "λ"
let g:mapping["m"] = "μ"
let g:mapping["n"] = "ν"
let g:mapping["o"] = "οὀὁὂὃὄὅὸό"
let g:mapping["p"] = "π"
let g:mapping["r"] = "ρῥῤ"
let g:mapping["s"] = "σς"
let g:mapping["t"] = "τ"
let g:mapping["u"] = "υὐὑὒὓὔὕὖὗὺύῠῡῢΰῦῧ"
let g:mapping["w"] = "ωὠὡὢὣὤὥὦὧὼώᾠᾡᾢᾣᾤᾥᾦᾧῲῳῴῶῷ"
let g:mapping["x"] = "χ"
let g:mapping["y"] = "θ"
let g:mapping["z"] = "ζ"

let g:mapping["A"] = "ΑἈἉἊἋἌἍἎἏᾺΆᾈᾉᾊᾋᾌᾍᾎᾏᾸᾹᾼ"
let g:mapping["B"] = "Β"
let g:mapping["C"] = "Ψ"
let g:mapping["D"] = "Δ"
let g:mapping["E"] = "ΕἘἙἚἛἜἝῈΈ"
let g:mapping["F"] = "Φ"
let g:mapping["G"] = "Γ"
let g:mapping["H"] = "ΗἨἩἪἫἬἭἮἯῊΉᾘᾙᾚᾛᾜᾝᾞᾟῌ"
let g:mapping["I"] = "ΙἸἹἺἻἼἽἾἿῚΊῘῙ"
let g:mapping["J"] = "Ξ"
let g:mapping["K"] = "Κ"
let g:mapping["L"] = "Λ"
let g:mapping["M"] = "Μ"
let g:mapping["N"] = "Ν"
let g:mapping["O"] = "ΟὈὉὊὋὌὍῸΌ"
let g:mapping["P"] = "Π"
let g:mapping["R"] = "ΡῬ"
let g:mapping["S"] = "ΣΣ"
let g:mapping["T"] = "Τ"
let g:mapping["U"] = "ΥὙὛὝὟῪΎῨῩ"
let g:mapping["W"] = "ΩὨὩὪὫὬὭὮὯῺΏᾨᾩᾪᾫᾬᾭᾮᾯῼ"
let g:mapping["X"] = "Χ"
let g:mapping["Y"] = "Θ"
let g:mapping["Z"] = "Ζ"

" let g:mapping["q"] = ""
" let g:mapping["v"] = ""

fun! CSelect(char)
   if a:char == "q"
      inoremap
   else
      let zahlen = "1234567890123456789012345678901234567890"
      let l = strlen(substitute(g:mapping[a:char],".","x","g"))
      let zahlen = strpart(zahlen, 0, l)
      let z = input(zahlen . "\n" . g:mapping[a:char] . "\n")
      let tmp = g:mapping[a:char]
      while z > 1
         let tmp = substitute(tmp,".","","")
         let z = z - 1
      endwhile
      let tmp = substitute(tmp,"\\(.\\).*","\\1","")
      exec "normal a" . tmp . "\<Esc>"
   endif
endfun

fun! Greek()
   for key in keys(g:mapping)
      if strlen(substitute(g:mapping[key],".","x","g")) > 1
         exec "inoremap " . key . " " . "<C-O>:call CSelect(\"" . key . "\")<CR>"
      else
         exec "inoremap " . key . " " . g:mapping[key]
      endif
   endfor
   inoremap q <C-O>:call CSelect("q")<CR>
endfun

fun! UnGreek()
   for key in keys(g:mapping)
      exec "iunmap " . key
   endfor
   iunmap q
endfun

command! -nargs=0 Greek call Greek()
command! -nargs=0 UnGreek call UnGreek()