Add built-in functions register_executing() and register_recording()

runtime/doc/eval.txt

@@ -6565,6 +6565,15 @@ readfile({fname} [, {binary} [, {max}]])
 		the result is an empty list.
 		Also see |writefile()|.
 
+register_executing()					*register_executing()*
+		Returns |TRUE| when the register contents are executing.
+		See |@|.
+
+register_recording()					*register_recording()*
+		Returns the named register character {0-9a-zA-Z"} when the
+		register contents are recording.  Otherwise, an empty string
+		is returned.  See |q|.
+
 reltime([{start} [, {end}]])				*reltime()*
 		Return an item that represents a time value.  The format of
 		the item depends on the system.  It can be passed to

runtime/doc/usr_41.txt

@@ -1016,6 +1016,8 @@ Various:					*various-functions*
 	getreg()		get contents of a register
 	getregtype()		get type of a register
 	setreg()		set contents and type of a register
+	regster_executing()	return the state of the register executing
+	regster_recording()	return the state of the register recording
 
 	shiftwidth()		effective value of 'shiftwidth'
 

src/evalfunc.c

@@ -306,6 +306,8 @@ static void f_pyxeval(typval_T *argvars, typval_T *rettv);
 #endif
 static void f_range(typval_T *argvars, typval_T *rettv);
 static void f_readfile(typval_T *argvars, typval_T *rettv);
+static void f_register_executing(typval_T *argvars, typval_T *rettv);
+static void f_register_recording(typval_T *argvars, typval_T *rettv);
 static void f_reltime(typval_T *argvars, typval_T *rettv);
 #ifdef FEAT_FLOAT
 static void f_reltimefloat(typval_T *argvars, typval_T *rettv);
@@ -754,6 +756,8 @@ static struct fst
 #endif
     {"range",		1, 3, f_range},
     {"readfile",	1, 3, f_readfile},
+    {"register_executing", 0, 0, f_register_executing},
+    {"register_recording", 0, 0, f_register_recording},
     {"reltime",		0, 2, f_reltime},
 #ifdef FEAT_FLOAT
     {"reltimefloat",	1, 1, f_reltimefloat},
@@ -8678,6 +8682,27 @@ f_readfile(typval_T *argvars, typval_T *rettv)
     fclose(fd);
 }
 
+/*
+ * "register_executing()" function
+ */
+    static void
+f_register_executing(typval_T *argvars, typval_T *rettv)
+{
+    rettv->vval.v_number = Exec_reg;
+}
+
+/*
+ * "register_recording()" function
+ */
+    static void
+f_register_recording(typval_T *argvars, typval_T *rettv)
+{
+    char_u regname[2] = {0, 0};
+    regname[0] = (char_u)Recording;
+    rettv->v_type = VAR_STRING;
+    rettv->vval.v_string = vim_strsave(regname);
+}
+
 #if defined(FEAT_RELTIME)
 static int list2proftime(typval_T *arg, proftime_T *tm);