vim-patch:9.1.0741: No way to get prompt for input()/confirm()

Problem:  No way to get prompt for input()/confirm()
Solution: add getcmdprompt() function (Shougo Matsushita)
          (Shougo Matsushita)

closes: vim/vim#15667

https://github.com/vim/vim/commit/6908428560a0d6ae27bf7af6fcb6dc362e31926c

Co-authored-by: Shougo Matsushita <Shougo.Matsu@gmail.com>

3 files changed, 49 insertions, 9 deletions

diff --git a/src/nvim/eval.lua b/src/nvim/eval.lua
index 2a3327b37b..4545ad1149 100644
--- a/src/nvim/eval.lua
+++ b/src/nvim/eval.lua
@@ -3594,8 +3594,8 @@ M.funcs = {
       Only works when the command line is being edited, thus
       requires use of |c_CTRL-\_e| or |c_CTRL-R_=|.
       See |:command-completion| for the return string.
-      Also see |getcmdtype()|, |setcmdpos()|, |getcmdline()| and
-      |setcmdline()|.
+      Also see |getcmdtype()|, |setcmdpos()|, |getcmdline()|,
+      |getcmdprompt()| and |setcmdline()|.
       Returns an empty string when completion is not defined.
     ]=],
     name = 'getcmdcompltype',
@@ -3605,13 +3605,13 @@ M.funcs = {
   },
   getcmdline = {
     desc = [=[
-      Return the current command-line.  Only works when the command
-      line is being edited, thus requires use of |c_CTRL-\_e| or
-      |c_CTRL-R_=|.
+      Return the current command-line input.  Only works when the
+      command line is being edited, thus requires use of
+      |c_CTRL-\_e| or |c_CTRL-R_=|.
       Example: >vim
       	cmap <F7> <C-\>eescape(getcmdline(), ' \')<CR>
-      <Also see |getcmdtype()|, |getcmdpos()|, |setcmdpos()| and
-      |setcmdline()|.
+      <Also see |getcmdtype()|, |getcmdpos()|, |setcmdpos()|,
+      |getcmdprompt()| and |setcmdline()|.
       Returns an empty string when entering a password or using
       |inputsecret()|.
     ]=],
@@ -3627,14 +3627,28 @@ M.funcs = {
       Only works when editing the command line, thus requires use of
       |c_CTRL-\_e| or |c_CTRL-R_=| or an expression mapping.
       Returns 0 otherwise.
-      Also see |getcmdtype()|, |setcmdpos()|, |getcmdline()| and
-      |setcmdline()|.
+      Also see |getcmdtype()|, |setcmdpos()|, |getcmdline()|,
+      |getcmdprompt()| and |setcmdline()|.
     ]=],
     name = 'getcmdpos',
     params = {},
     returns = 'integer',
     signature = 'getcmdpos()',
   },
+  getcmdprompt = {
+    desc = [=[
+      Return the current command-line prompt when using functions
+      like |input()| or |confirm()|.
+      Only works when the command line is being edited, thus
+      requires use of |c_CTRL-\_e| or |c_CTRL-R_=|.
+      Also see |getcmdtype()|, |getcmdline()|, |getcmdpos()|,
+      |setcmdpos()| and |setcmdline()|.
+    ]=],
+    name = 'getcmdprompt',
+    params = {},
+    returns = 'string',
+    signature = 'getcmdprompt()',
+  },
   getcmdscreenpos = {
     desc = [=[
       Return the screen position of the cursor in the command line
diff --git a/src/nvim/eval/funcs.c b/src/nvim/eval/funcs.c
index e8b9288717..4a96c9a3f3 100644
--- a/src/nvim/eval/funcs.c
+++ b/src/nvim/eval/funcs.c
@@ -813,6 +813,8 @@ static void f_confirm(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
   const char *message = tv_get_string_chk(&argvars[0]);
   if (message == NULL) {
     error = true;
+  } else {
+    set_prompt(message);
   }
   if (argvars[1].v_type != VAR_UNKNOWN) {
     buttons = tv_get_string_buf_chk(&argvars[1], buf);
diff --git a/src/nvim/ex_getln.c b/src/nvim/ex_getln.c
index 6a57b3ab78..7eb4fe67a1 100644
--- a/src/nvim/ex_getln.c
+++ b/src/nvim/ex_getln.c
@@ -4132,6 +4132,28 @@ void f_getcmdpos(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
   rettv->vval.v_number = p != NULL ? p->cmdpos + 1 : 0;
 }
 
+static char current_prompt[CMDBUFFSIZE + 1] = "";
+
+/// Get current command line prompt.
+static char *get_prompt(void)
+{
+  return current_prompt;
+}
+
+/// Set current command line prompt.
+void set_prompt(const char *str)
+{
+  xstrlcpy(current_prompt, str, sizeof(current_prompt));
+}
+
+/// "getcmdprompt()" function
+void f_getcmdprompt(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
+{
+  CmdlineInfo *p = get_ccline_ptr();
+  rettv->v_type = VAR_STRING;
+  rettv->vval.v_string = p != NULL ? xstrdup(get_prompt()) : NULL;
+}
+
 /// "getcmdscreenpos()" function
 void f_getcmdscreenpos(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
 {
@@ -4730,6 +4752,8 @@ void get_user_input(const typval_T *const argvars, typval_T *const rettv, const
   const bool cmd_silent_save = cmd_silent;
 
   cmd_silent = false;  // Want to see the prompt.
+  set_prompt(prompt);
+
   // Only the part of the message after the last NL is considered as
   // prompt for the command line, unlsess cmdline is externalized
   const char *p = prompt;