patch 7.4.1996

Problem:    Capturing the output of a command takes a few commands.
Solution:   Add evalcmd().

runtime/doc/eval.txt

@@ -1961,6 +1961,7 @@ diff_hlID({lnum}, {col})	Number	diff highlighting at {lnum}/{col}
 empty({expr})			Number	|TRUE| if {expr} is empty
 escape({string}, {chars})	String	escape {chars} in {string} with '\'
 eval({string})			any	evaluate {string} into its value
+evalcmd({command})		String	execute {command} and get the output
 eventhandler()			Number	|TRUE| if inside an event handler
 executable({expr})		Number	1 if executable {expr} exists
 exepath({expr})			String  full path of the command {expr}
@@ -3231,6 +3232,15 @@ eval({string})	Evaluate {string} and return the result.  Especially useful to
 		them.  Also works for |Funcref|s that refer to existing
 		functions.
 
+evalcmd({command})					*evalcmd()*
+		Execute Ex {command} and return the output as a string.  This
+		is equivalent to: >
+			redir => var
+			{command}
+			redir END
+<		To get a list of lines use: >
+			split(evalcmd(cmd), "\n")
+
 eventhandler()						*eventhandler()*
 		Returns 1 when inside an event handler.  That is that Vim got
 		interrupted while waiting for the user to type a character,

src/Makefile

@@ -2023,6 +2023,7 @@ test_arglist \
 	test_cmdline \
 	test_cursor_func \
 	test_delete \
+	test_evalcmd \
 	test_ex_undo \
 	test_expand \
 	test_expand_dllpath \

src/eval.c

@@ -555,6 +555,7 @@ static void f_diff_hlID(typval_T *argvars, typval_T *rettv);
 static void f_empty(typval_T *argvars, typval_T *rettv);
 static void f_escape(typval_T *argvars, typval_T *rettv);
 static void f_eval(typval_T *argvars, typval_T *rettv);
+static void f_evalcmd(typval_T *argvars, typval_T *rettv);
 static void f_eventhandler(typval_T *argvars, typval_T *rettv);
 static void f_executable(typval_T *argvars, typval_T *rettv);
 static void f_exepath(typval_T *argvars, typval_T *rettv);
@@ -1133,6 +1134,7 @@ set_internal_string_var(char_u *name, char_u *value)
 }
 
 static lval_T	*redir_lval = NULL;
+#define EVALCMD_BUSY (redir_lval == (lval_T *)&redir_lval)
 static garray_T redir_ga;	/* only valid when redir_lval is not NULL */
 static char_u	*redir_endp = NULL;
 static char_u	*redir_varname = NULL;
@@ -1250,6 +1252,12 @@ var_redir_stop(void)
 {
     typval_T	tv;
 
+    if (EVALCMD_BUSY)
+    {
+	redir_lval = NULL;
+	return;
+    }
+
     if (redir_lval != NULL)
     {
 	/* If there was no error: assign the text to the variable. */
@@ -8556,6 +8564,7 @@ static struct fst
     {"empty",		1, 1, f_empty},
     {"escape",		2, 2, f_escape},
     {"eval",		1, 1, f_eval},
+    {"evalcmd",		1, 1, f_evalcmd},
     {"eventhandler",	0, 0, f_eventhandler},
     {"executable",	1, 1, f_executable},
     {"exepath",		1, 1, f_exepath},
@@ -11336,6 +11345,36 @@ f_eval(typval_T *argvars, typval_T *rettv)
 	EMSG(_(e_trailing));
 }
 
+/*
+ * "evalcmd()" function
+ */
+    static void
+f_evalcmd(typval_T *argvars, typval_T *rettv)
+{
+    char_u	*s;
+
+    rettv->vval.v_string = NULL;
+    rettv->v_type = VAR_STRING;
+
+    s = get_tv_string_chk(&argvars[0]);
+    if (s != NULL)
+    {
+	redir_vname = TRUE;
+	redir_lval = (lval_T *)&redir_lval;
+	ga_init2(&redir_ga, (int)sizeof(char), 500);
+
+	if (do_cmdline_cmd(s) == OK)
+	    rettv->vval.v_string = redir_ga.ga_data;
+	else
+	    vim_free(redir_ga.ga_data);
+
+	redir_ga.ga_data = NULL;
+	redir_vname = FALSE;
+	redir_lval = NULL;
+    }
+
+}
+
 /*
  * "eventhandler()" function
  */

src/testdir/test_alot.vim

@@ -5,9 +5,10 @@ source test_assign.vim
 source test_autocmd.vim
 source test_cursor_func.vim
 source test_delete.vim
+source test_evalcmd.vim
 source test_ex_undo.vim
-source test_expr.vim
 source test_expand.vim
+source test_expr.vim
 source test_expand_dllpath.vim
 source test_feedkeys.vim
 source test_fnamemodify.vim

src/testdir/test_evalcmd.vim

@@ -0,0 +1,8 @@
+" test evalcmd()
+
+func Test_evalcmd()
+  call assert_equal("\nnocompatible", evalcmd('set compatible?'))
+  call assert_equal("\nsomething\nnice", evalcmd('echo "something\nnice"'))
+  call assert_fails('call evalcmd("doesnotexist")', 'E492:')
+endfunc
+

src/version.c

@@ -758,6 +758,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    1996,
 /**/
     1995,
 /**/