Make confirm dialog take arbitrary keys

Confirm now takes the list of options, list of keys to select them and
the default value. Returned values are always a 1-based index into the
list (like SelectFromList) or -1 to mean esc/ctrl-c.

This uses a nice popup dialog in vim and a crappy input on neovim.

autoload/vimspector/internal/neopopup.vim

@@ -82,29 +82,52 @@ endfunction
 
 function! vimspector#internal#neopopup#Confirm( confirm_id,
                                               \ text,
-                                              \ default_value ) abort
+                                              \ options,
+                                              \ default_value,
+                                              \ keys ) abort
 
   " Neovim doesn't have an equivalent of popup_dialog, and it's way too much
   " effort to write one, so we just use confirm().
-  let result = confirm( a:text, '&Yes &No &Default', 3 )
+  let prompt = a:text
+  for opt in a:options
+    let prompt .= ' ' . opt
+  endfor
+  let prompt .= ': '
+
+  " Annoyingly we can't use confirm() here because for some reason it doesn't
+  " render properly in a channel callback. So we use input() and mimic dialog
+  " behaviour.
+  try
+    let result = input( prompt, a:keys[ a:default_value - 1 ] )
+  catch /.*/
+    let result = -1
+  endtry
 
   " Map the results to what popup_menu_filter would return (ok s:ConfirmCallback
   " in popup.vim)
-  if result == 2
-    " No is represented as 0
-    let result = 0
-  elseif result == 0
+  if result == ''
     " User pressed ESC/ctrl-c
     let result = -1
-  elseif result == 3
-    " Default
-    let result = a:default_value
+  else
+    let index = 1
+    for k in a:keys
+      if k ==? result
+        let result = index
+        break
+      endif
+      let index += 2
+    endfor
+
+    if index >= len( a:keys )
+      let result = -1
+    endif
   endif
 
   py3 __import__( 'vimspector', fromlist = [ 'utils' ] ).utils.ConfirmCallback(
         \ int( vim.eval( 'a:confirm_id' ) ),
         \ int( vim.eval( 'result' ) ) )
 endfunction
+
 " Boilerplate {{{
 let &cpoptions=s:save_cpo
 unlet s:save_cpo

autoload/vimspector/internal/popup.vim

@@ -42,13 +42,10 @@ function! s:UpdatePopup( id )
   call popup_settext( a:id, buf )
 endfunction
 
-function! s:YesNoDefaultFilter( default_value, id, key ) abort
+function! s:ConfirmKeyFilter( keys, id, key ) abort
   if a:key ==# "\<CR>"
     call popup_close( a:id, s:current_selection + 1 )
     return 1
-  elseif a:key ==# 'D' || a:key ==# 'd'
-    call popup_close( a:id, a:default_value )
-    return 1
   elseif index( [ "\<Tab>", "\<Right>" ], a:key ) >= 0
     let s:current_selection = ( s:current_selection + 1 ) % len( s:selections )
     call s:UpdatePopup( a:id )
@@ -58,9 +55,19 @@ function! s:YesNoDefaultFilter( default_value, id, key ) abort
           \ ? len( s:selections ) - 1: s:current_selection - 1
     call s:UpdatePopup( a:id )
     return 1
+  elseif a:key ==# "\<Esc>" || a:key ==# "\<C-c>"
+    call popup_close( a:id, -1 )
+    return 1
   endif
 
-  return popup_filter_yesno( a:id, a:key )
+  let index = 1
+  for key in a:keys
+    if a:key ==? key
+      call popup_close( a:id, index )
+      return 1
+    endif
+    let index += 1
+  endfor
 endfunction
 
 function! s:ConfirmCallback( confirm_id, id, result ) abort
@@ -90,7 +97,8 @@ function! vimspector#internal#popup#Confirm(
       \ confirm_id,
       \ text,
       \ options,
-      \ default_value ) abort
+      \ default_value,
+      \ keys ) abort
 
   silent! call prop_type_add( 'VimspectorSelectedItem', {
         \ 'highlight': 'PMenuSel'
@@ -112,7 +120,7 @@ function! vimspector#internal#popup#Confirm(
 
   let config = {
         \   'callback': function( 's:ConfirmCallback', [ a:confirm_id ] ),
-        \   'filter': function( 's:YesNoDefaultFilter', [ a:default_value ] ),
+        \   'filter': function( 's:ConfirmKeyFilter', [ a:keys ] ),
         \   'mapping': v:false,
         \ }
   let config = vimspector#internal#popup#SetBorderChars( config )