patch 8.2.2662: there is no way to avoid some escape sequences

Problem:    There is no way to avoid some escape sequences.
Solution:   Suppress escape sequences when the --not-a-term argument is used.
            (Gary Johnson)

runtime/doc/eval.txt

@@ -439,8 +439,8 @@ Changing the order of items in a list: >
 
 For loop ~
 
-The |:for| loop executes commands for each item in a list.  A variable is set
-to each item in the list in sequence.  Example: >
+The |:for| loop executes commands for each item in a List, String or Blob.
+A variable is set to each item in sequence.  Example with a List: >
 	:for item in mylist
 	:   call Doit(item)
 	:endfor
@@ -457,7 +457,7 @@ If all you want to do is modify each item in the list then the |map()|
 function will be a simpler method than a for loop.
 
 Just like the |:let| command, |:for| also accepts a list of variables.  This
-requires the argument to be a list of lists. >
+requires the argument to be a List of Lists. >
 	:for [lnum, col] in [[1, 3], [2, 8], [3, 0]]
 	:   call Doit(lnum, col)
 	:endfor
@@ -473,6 +473,14 @@ It is also possible to put remaining items in a List variable: >
 	:   endif
 	:endfor
 
+For a Blob one byte at a time is used.
+
+For a String one character, including any composing characters, is used as a
+String.  Example: >
+	for c in text
+	  echo 'This character is ' .. c
+	endfor
+
 
 List functions ~
 						*E714*

src/errors.h

@@ -386,4 +386,8 @@ EXTERN char e_text_found_after_enddef_str[]
 EXTERN char e_string_required_for_argument_nr[]
 	INIT(= N_("E1174: String required for argument %d"));
 EXTERN char e_non_empty_string_required_for_argument_nr[]
-	INIT(= N_("E1142: Non-empty string required for argument %d"));
+	INIT(= N_("E1175: Non-empty string required for argument %d"));
+EXTERN char e_misplaced_command_modifier[]
+	INIT(= N_("E1176: Misplaced command modifier"));
+EXTERN char e_for_loop_on_str_not_supported[]
+	INIT(= N_("E1177: For loop on %s not supported"));

src/eval.c

@@ -41,6 +41,8 @@ typedef struct
     list_T	*fi_list;	// list being used
     int		fi_bi;		// index of blob
     blob_T	*fi_blob;	// blob being used
+    char_u	*fi_string;	// copy of string being used
+    int		fi_byte_idx;	// byte index in fi_string
 } forinfo_T;
 
 static int tv_op(typval_T *tv1, typval_T *tv2, char_u  *op);
@@ -1738,6 +1740,14 @@ eval_for_line(
 		}
 		clear_tv(&tv);
 	    }
+	    else if (tv.v_type == VAR_STRING)
+	    {
+		fi->fi_byte_idx = 0;
+		fi->fi_string = tv.vval.v_string;
+		tv.vval.v_string = NULL;
+		if (fi->fi_string == NULL)
+		    fi->fi_string = vim_strsave((char_u *)"");
+	    }
 	    else
 	    {
 		emsg(_(e_listreq));
@@ -1790,7 +1800,25 @@ next_for_item(void *fi_void, char_u *arg)
 	tv.vval.v_number = blob_get(fi->fi_blob, fi->fi_bi);
 	++fi->fi_bi;
 	return ex_let_vars(arg, &tv, TRUE, fi->fi_semicolon,
-				       fi->fi_varcount, flag, NULL) == OK;
+					    fi->fi_varcount, flag, NULL) == OK;
+    }
+
+    if (fi->fi_string != NULL)
+    {
+	typval_T	tv;
+	int		len;
+
+	len = mb_ptr2len(fi->fi_string + fi->fi_byte_idx);
+	if (len == 0)
+	    return FALSE;
+	tv.v_type = VAR_STRING;
+	tv.v_lock = VAR_FIXED;
+	tv.vval.v_string = vim_strnsave(fi->fi_string + fi->fi_byte_idx, len);
+	fi->fi_byte_idx += len;
+	result = ex_let_vars(arg, &tv, TRUE, fi->fi_semicolon,
+					    fi->fi_varcount, flag, NULL) == OK;
+	vim_free(tv.vval.v_string);
+	return result;
     }
 
     item = fi->fi_lw.lw_item;
@@ -1800,7 +1828,7 @@ next_for_item(void *fi_void, char_u *arg)
     {
 	fi->fi_lw.lw_item = item->li_next;
 	result = (ex_let_vars(arg, &item->li_tv, TRUE, fi->fi_semicolon,
-				      fi->fi_varcount, flag, NULL) == OK);
+					   fi->fi_varcount, flag, NULL) == OK);
     }
     return result;
 }
@@ -1813,13 +1841,17 @@ free_for_info(void *fi_void)
 {
     forinfo_T    *fi = (forinfo_T *)fi_void;
 
-    if (fi != NULL && fi->fi_list != NULL)
+    if (fi == NULL)
+	return;
+    if (fi->fi_list != NULL)
     {
 	list_rem_watch(fi->fi_list, &fi->fi_lw);
 	list_unref(fi->fi_list);
     }
-    if (fi != NULL && fi->fi_blob != NULL)
+    else if (fi->fi_blob != NULL)
 	blob_unref(fi->fi_blob);
+    else
+	vim_free(fi->fi_string);
     vim_free(fi);
 }
 

src/evalvars.c

@@ -789,8 +789,11 @@ ex_let(exarg_T *eap)
 	{
 	    if (vim9script)
 	    {
-		// Vim9 declaration ":var name: type"
-		arg = vim9_declare_scriptvar(eap, arg);
+		if (!ends_excmd2(eap->cmd, skipwhite(argend)))
+		    semsg(_(e_trailing_arg), argend);
+		else
+		    // Vim9 declaration ":var name: type"
+		    arg = vim9_declare_scriptvar(eap, arg);
 	    }
 	    else
 	    {

src/ex_eval.c

@@ -1154,6 +1154,32 @@ ex_while(exarg_T *eap)
 	    ++cstack->cs_looplevel;
 	    cstack->cs_line[cstack->cs_idx] = -1;
 	}
+	else
+	{
+	    if (in_vim9script() && SCRIPT_ID_VALID(current_sctx.sc_sid))
+	    {
+		scriptitem_T	*si = SCRIPT_ITEM(current_sctx.sc_sid);
+		int		i;
+
+		// Any variables defined in the previous round are no longer
+		// visible.
+		for (i = cstack->cs_script_var_len[cstack->cs_idx];
+					       i < si->sn_var_vals.ga_len; ++i)
+		{
+		    svar_T	*sv = ((svar_T *)si->sn_var_vals.ga_data) + i;
+
+		    // sv_name is set to NULL if it was already removed.  This
+		    // happens when it was defined in an inner block and no
+		    // functions were defined there.
+		    if (sv->sv_name != NULL)
+			// Remove a variable declared inside the block, if it
+			// still exists, from sn_vars.
+			hide_script_var(si, i, FALSE);
+		}
+		cstack->cs_script_var_len[cstack->cs_idx] =
+							si->sn_var_vals.ga_len;
+	    }
+	}
 	cstack->cs_flags[cstack->cs_idx] =
 			       eap->cmdidx == CMD_while ? CSF_WHILE : CSF_FOR;
 
@@ -1175,6 +1201,9 @@ ex_while(exarg_T *eap)
 	    void	*fi;
 	    evalarg_T	evalarg;
 
+	    /*
+	     * ":for var in list-expr"
+	     */
 	    CLEAR_FIELD(evalarg);
 	    evalarg.eval_flags = skip ? 0 : EVAL_EVALUATE;
 	    if (getline_equal(eap->getline, eap->cookie, getsourceline))
@@ -1183,9 +1212,6 @@ ex_while(exarg_T *eap)
 		evalarg.eval_cookie = eap->cookie;
 	    }
 
-	    /*
-	     * ":for var in list-expr"
-	     */
 	    if ((cstack->cs_lflags & CSL_HAD_LOOP) != 0)
 	    {
 		// Jumping here from a ":continue" or ":endfor": use the
@@ -1384,10 +1410,8 @@ ex_endwhile(exarg_T *eap)
 		&& dbg_check_skipped(eap))
 	    (void)do_intthrow(cstack);
 
-	/*
-	 * Set loop flag, so do_cmdline() will jump back to the matching
-	 * ":while" or ":for".
-	 */
+	// Set loop flag, so do_cmdline() will jump back to the matching
+	// ":while" or ":for".
 	cstack->cs_lflags |= CSL_HAD_ENDLOOP;
     }
 }

src/main.c

@@ -995,6 +995,19 @@ is_not_a_term()
     return params.not_a_term;
 }
 
+/*
+ * Return TRUE when the --not-a-term argument was found or the GUI is in use.
+ */
+    static int
+is_not_a_term_or_gui()
+{
+    return params.not_a_term
+#ifdef FEAT_GUI
+			    || gui.in_use
+#endif
+	;
+}
+
 
 // When TRUE in a safe state when starting to wait for a character.
 static int	was_safe = FALSE;
@@ -1528,9 +1541,7 @@ getout(int exitval)
 #endif
 
     // Position the cursor on the last screen line, below all the text
-#ifdef FEAT_GUI
-    if (!gui.in_use)
-#endif
+    if (!is_not_a_term_or_gui())
 	windgoto((int)Rows - 1, 0);
 
 #if defined(FEAT_EVAL) || defined(FEAT_SYN_HL)
@@ -1640,9 +1651,7 @@ getout(int exitval)
     }
 
     // Position the cursor again, the autocommands may have moved it
-#ifdef FEAT_GUI
-    if (!gui.in_use)
-#endif
+    if (!is_not_a_term_or_gui())
 	windgoto((int)Rows - 1, 0);
 
 #ifdef FEAT_JOB_CHANNEL

src/os_unix.c

@@ -3343,7 +3343,7 @@ exit_scroll(void)
 	else
 	    out_char('\n');
     }
-    else
+    else if (!is_not_a_term())
     {
 	restore_cterm_colors();		// get original colors back
 	msg_clr_eos_force();		// clear the rest of the display
@@ -3370,9 +3370,12 @@ mch_exit(int r)
     {
 	settmode(TMODE_COOK);
 #ifdef FEAT_TITLE
-	// restore xterm title and icon name
-	mch_restore_title(SAVE_RESTORE_BOTH);
-	term_pop_title(SAVE_RESTORE_BOTH);
+	if (!is_not_a_term())
+	{
+	    // restore xterm title and icon name
+	    mch_restore_title(SAVE_RESTORE_BOTH);
+	    term_pop_title(SAVE_RESTORE_BOTH);
+	}
 #endif
 	/*
 	 * When t_ti is not empty but it doesn't cause swapping terminal

src/term.c

@@ -3365,8 +3365,9 @@ win_new_shellsize(void)
 	ui_new_shellsize();
     if (old_Rows != Rows)
     {
-	// if 'window' uses the whole screen, keep it using that
-	if (p_window == old_Rows - 1 || old_Rows == 0)
+	// If 'window' uses the whole screen, keep it using that.
+	// Don't change it when set with "-w size" on the command line.
+	if (p_window == old_Rows - 1 || (old_Rows == 0 && p_window == 0))
 	    p_window = Rows - 1;
 	old_Rows = Rows;
 	shell_new_rows();	// update window sizes

src/testdir/test_eval_stuff.vim

@@ -66,7 +66,7 @@ endfunc
 
 func Test_for_invalid()
   call assert_fails("for x in 99", 'E714:')
-  call assert_fails("for x in 'asdf'", 'E714:')
+  call assert_fails("for x in function('winnr')", 'E714:')
   call assert_fails("for x in {'a': 9}", 'E714:')
 
   if 0

src/testdir/test_regexp_latin.vim

@@ -924,8 +924,17 @@ func Test_regexp_error()
   call assert_fails("call matchlist('x x', '\\%#=1 \\ze*')", 'E888:')
   call assert_fails("call matchlist('x x', '\\%#=2 \\zs*')", 'E888:')
   call assert_fails("call matchlist('x x', '\\%#=2 \\ze*')", 'E888:')
-  call assert_fails('exe "normal /\\%#=1\\%[x\\%[x]]\<CR>"', 'E369:')
   call assert_fails("call matchstr('abcd', '\\%o841\\%o142')", 'E678:')
+  call assert_fails("call matchstr('abcd', '\\%#=2\\%2147483647c')", 'E951:')
+  call assert_fails("call matchstr('abcd', '\\%#=2\\%2147483647l')", 'E951:')
+  call assert_fails("call matchstr('abcd', '\\%#=2\\%2147483647v')", 'E951:')
+  call assert_fails('exe "normal /\\%#=1\\%[x\\%[x]]\<CR>"',   'E369:')
+  call assert_fails('exe "normal /\\%#=2\\%2147483647l\<CR>"', 'E951:')
+  call assert_fails('exe "normal /\\%#=2\\%2147483647c\<CR>"', 'E951:')
+  call assert_fails('exe "normal /\\%#=2\\%102261126v\<CR>"',  'E951:')
+  call assert_fails('exe "normal /\\%#=2\\%2147483646l\<CR>"', 'E486:')
+  call assert_fails('exe "normal /\\%#=2\\%2147483646c\<CR>"', 'E486:')
+  call assert_fails('exe "normal /\\%#=2\\%102261125v\<CR>"',  'E486:')
   call assert_equal('', matchstr('abcd', '\%o181\%o142'))
 endfunc
 

src/testdir/test_startup.vim

@@ -860,10 +860,12 @@ func Test_t_arg()
         \ 'Xtags')
   call writefile(['    first', '    second', '    third'], 'Xfile1')
 
-  if RunVim(before, after, '-t second')
-    call assert_equal(['Xfile1:L2C5'], readfile('Xtestout'))
-    call delete('Xtestout')
-  endif
+  for t_arg in ['-t second', '-tsecond']
+    if RunVim(before, after, '-t second')
+      call assert_equal(['Xfile1:L2C5'], readfile('Xtestout'), t_arg)
+      call delete('Xtestout')
+    endif
+  endfor
 
   call delete('Xtags')
   call delete('Xfile1')
@@ -1041,10 +1043,37 @@ func Test_io_not_a_terminal()
         \ 'Vim: Warning: Input is not from a terminal'], l)
 endfunc
 
+" Test for --not-a-term avoiding escape codes.
+func Test_not_a_term()
+  CheckUnix
+  CheckNotGui
+
+  if &shellredir =~ '%s'
+    let redir = printf(&shellredir,  'Xvimout')
+  else
+    let redir = &shellredir .. ' Xvimout'
+  endif
+
+  " Without --not-a-term there are a few escape sequences.
+  " This will take 2 seconds because of the missing --not-a-term
+  let cmd = GetVimProg() .. ' --cmd quit ' .. redir
+  exe "silent !" . cmd
+  call assert_match("\<Esc>", readfile('Xvimout')->join())
+  call delete('Xvimout')
+
+  " With --not-a-term there are no escape sequences.
+  let cmd = GetVimProg() .. ' --not-a-term --cmd quit ' .. redir
+  exe "silent !" . cmd
+  call assert_notmatch("\<Esc>", readfile('Xvimout')->join())
+  call delete('Xvimout')
+endfunc
+
+
 " Test for the "-w scriptout" argument
 func Test_w_arg()
   " Can't catch the output of gvim.
   CheckNotGui
+
   call writefile(["iVim Editor\<Esc>:q!\<CR>"], 'Xscriptin', 'b')
   if RunVim([], [], '-s Xscriptin -w Xscriptout')
     call assert_equal(["iVim Editor\e:q!\r"], readfile('Xscriptout'))
@@ -1060,6 +1089,16 @@ func Test_w_arg()
     call assert_equal("Cannot open for script output: \"Xdir\"\n", m)
     call delete("Xdir", 'rf')
   endif
+
+  " A number argument sets the 'window' option
+  call writefile(["iwindow \<C-R>=&window\<CR>\<Esc>:wq! Xresult\<CR>"], 'Xscriptin', 'b')
+  for w_arg in ['-w 17', '-w17']
+    if RunVim([], [], '-s Xscriptin ' .. w_arg)
+      call assert_equal(["window 17"], readfile('Xresult'), w_arg)
+      call delete('Xresult')
+    endif
+  endfor
+  call delete('Xscriptin')
 endfunc
 
 " Test for the "-s scriptin" argument

src/testdir/test_vim9_assign.vim

@@ -1290,6 +1290,8 @@ def Test_var_declaration()
     other = 1234
     g:other_var = other
 
+    var xyz: string  # comment
+
     # type is inferred
     var s:dict = {['a']: 222}
     def GetDictVal(key: any)
@@ -1365,7 +1367,7 @@ def Test_var_declaration_fails()
     vim9script
     var 9var: string
   END
-  CheckScriptFailure(lines, 'E475:')
+  CheckScriptFailure(lines, 'E488:')
 
   CheckDefFailure(['var foo.bar = 2'], 'E1087:')
   CheckDefFailure(['var foo[3] = 2'], 'E1087:')
@@ -1617,6 +1619,11 @@ def Test_expr_error_no_assign()
       echo x
   END
   CheckScriptFailureList(lines, ['E1154:', 'E121:'])
+
+  lines =<< trim END
+      var x: string  'string'
+  END
+  CheckDefAndScriptFailure(lines, 'E488:')
 enddef
 
 

src/testdir/test_vim9_disassemble.vim

@@ -1061,7 +1061,6 @@ def Test_disassemble_for_loop_eval()
         '\d STORE -1 in $1\_s*' ..
         '\d PUSHS "\["one", "two"\]"\_s*' ..
         '\d BCALL eval(argc 1)\_s*' ..
-        '\d CHECKTYPE list<any> stack\[-1\]\_s*' ..
         '\d FOR $1 -> \d\+\_s*' ..
         '\d STORE $2\_s*' ..
         'res ..= str\_s*' ..
@@ -1071,7 +1070,7 @@ def Test_disassemble_for_loop_eval()
         '\d\+ CONCAT\_s*' ..
         '\d\+ STORE $0\_s*' ..
         'endfor\_s*' ..
-        '\d\+ JUMP -> 6\_s*' ..
+        '\d\+ JUMP -> 5\_s*' ..
         '\d\+ DROP\_s*' ..
         'return res\_s*' ..
         '\d\+ LOAD $0\_s*' ..

src/testdir/test_vim9_script.vim

@@ -2263,6 +2263,13 @@ def Test_for_outside_of_function()
     endfor
     assert_equal(['', '0', '1', '2', '3'], getline(1, '$'))
     bwipe!
+
+    var result = ''
+    for i in [1, 2, 3]
+      var loop = ' loop ' .. i
+      result ..= loop
+    endfor
+    assert_equal(' loop 1 loop 2 loop 3', result)
   END
   writefile(lines, 'Xvim9for.vim')
   source Xvim9for.vim
@@ -2315,6 +2322,25 @@ def Test_for_loop()
     res ..= n .. s
   endfor
   assert_equal('1a2b', res)
+
+  # loop over string
+  res = ''
+  for c in 'aéc̀d'
+    res ..= c .. '-'
+  endfor
+  assert_equal('a-é-c̀-d-', res)
+
+  res = ''
+  for c in ''
+    res ..= c .. '-'
+  endfor
+  assert_equal('', res)
+
+  res = ''
+  for c in test_null_string()
+    res ..= c .. '-'
+  endfor
+  assert_equal('', res)
 enddef
 
 def Test_for_loop_fails()
@@ -2326,10 +2352,17 @@ def Test_for_loop_fails()
   CheckDefFailure(['var x = 5', 'for x in range(5)'], 'E1017:')
   CheckScriptFailure(['def Func(arg: any)', 'for arg in range(5)', 'enddef', 'defcompile'], 'E1006:')
   delfunc! g:Func
-  CheckDefFailure(['for i in "text"'], 'E1012:')
   CheckDefFailure(['for i in xxx'], 'E1001:')
   CheckDefFailure(['endfor'], 'E588:')
   CheckDefFailure(['for i in range(3)', 'echo 3'], 'E170:')
+
+  # wrong type detected at compile time
+  CheckDefFailure(['for i in {a: 1}', 'echo 3', 'endfor'], 'E1177: For loop on dict not supported')
+
+  # wrong type detected at runtime
+  g:adict = {a: 1}
+  CheckDefExecFailure(['for i in g:adict', 'echo 3', 'endfor'], 'E1177: For loop on dict not supported')
+  unlet g:adict
 enddef
 
 def Test_for_loop_script_var()

src/testdir/test_vimscript.vim

@@ -7484,6 +7484,26 @@ func Test_trinary_expression()
   call assert_equal(v:false, eval(string(v:false)))
 endfunction
 
+func Test_for_over_string()
+  let res = ''
+  for c in 'aéc̀d'
+    let res ..= c .. '-'
+  endfor
+  call assert_equal('a-é-c̀-d-', res)
+
+  let res = ''
+  for c in ''
+    let res ..= c .. '-'
+  endfor
+  call assert_equal('', res)
+
+  let res = ''
+  for c in test_null_string()
+    let res ..= c .. '-'
+  endfor
+  call assert_equal('', res)
+endfunc
+
 "-------------------------------------------------------------------------------
 " Modelines								    {{{1
 " vim: ts=8 sw=2 sts=2 expandtab tw=80 fdm=marker

src/version.c

@@ -750,6 +750,26 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    2662,
+/**/
+    2661,
+/**/
+    2660,
+/**/
+    2659,
+/**/
+    2658,
+/**/
+    2657,
+/**/
+    2656,
+/**/
+    2655,
+/**/
+    2654,
+/**/
+    2653,
 /**/
     2652,
 /**/

src/vim9compile.c

@@ -7264,11 +7264,15 @@ compile_for(char_u *arg_start, cctx_T *cctx)
     }
     arg_end = arg;
 
-    // Now that we know the type of "var", check that it is a list, now or at
-    // runtime.
+    // If we know the type of "var" and it is a not a list or string we can
+    // give an error now.
     vartype = ((type_T **)stack->ga_data)[stack->ga_len - 1];
-    if (need_type(vartype, &t_list_any, -1, 0, cctx, FALSE, FALSE) == FAIL)
+    if (vartype->tt_type != VAR_LIST && vartype->tt_type != VAR_STRING
+						&& vartype->tt_type != VAR_ANY)
     {
+	// TODO: support Blob
+	semsg(_(e_for_loop_on_str_not_supported),
+					       vartype_name(vartype->tt_type));
 	drop_scope(cctx);
 	return NULL;
     }

src/vim9execute.c

@@ -1067,13 +1067,22 @@ char_from_string(char_u *str, varnumber_T index)
 	return NULL;
     slen = STRLEN(str);
 
-    // do the same as for a list: a negative index counts from the end
+    // Do the same as for a list: a negative index counts from the end.
+    // Optimization to check the first byte to be below 0x80 (and no composing
+    // character follows) makes this a lot faster.
     if (index < 0)
     {
 	int	clen = 0;
 
 	for (nbyte = 0; nbyte < slen; ++clen)
-	    nbyte += mb_ptr2len(str + nbyte);
+	{
+	    if (str[nbyte] < 0x80 && str[nbyte + 1] < 0x80)
+		++nbyte;
+	    else if (enc_utf8)
+		nbyte += utfc_ptr2len(str + nbyte);
+	    else
+		nbyte += mb_ptr2len(str + nbyte);
+	}
 	nchar = clen + index;
 	if (nchar < 0)
 	    // unlike list: index out of range results in empty string
@@ -1081,7 +1090,14 @@ char_from_string(char_u *str, varnumber_T index)
     }
 
     for (nbyte = 0; nchar > 0 && nbyte < slen; --nchar)
-	nbyte += mb_ptr2len(str + nbyte);
+    {
+	if (str[nbyte] < 0x80 && str[nbyte + 1] < 0x80)
+	    ++nbyte;
+	else if (enc_utf8)
+	    nbyte += utfc_ptr2len(str + nbyte);
+	else
+	    nbyte += mb_ptr2len(str + nbyte);
+    }
     if (nbyte >= slen)
 	return NULL;
     return vim_strnsave(str + nbyte, mb_ptr2len(str + nbyte));
@@ -2725,36 +2741,76 @@ call_def_function(
 	    // top of a for loop
 	    case ISN_FOR:
 		{
-		    list_T	*list = STACK_TV_BOT(-1)->vval.v_list;
+		    typval_T	*ltv = STACK_TV_BOT(-1);
 		    typval_T	*idxtv =
 				   STACK_TV_VAR(iptr->isn_arg.forloop.for_idx);
 
-		    // push the next item from the list
 		    if (GA_GROW(&ectx.ec_stack, 1) == FAIL)
 			goto failed;
-		    ++idxtv->vval.v_number;
-		    if (list == NULL || idxtv->vval.v_number >= list->lv_len)
+		    if (ltv->v_type == VAR_LIST)
 		    {
-			// past the end of the list, jump to "endfor"
-			ectx.ec_iidx = iptr->isn_arg.forloop.for_end;
-			may_restore_cmdmod(&funclocal);
-		    }
-		    else if (list->lv_first == &range_list_item)
-		    {
-			// non-materialized range() list
-			tv = STACK_TV_BOT(0);
-			tv->v_type = VAR_NUMBER;
-			tv->v_lock = 0;
-			tv->vval.v_number = list_find_nr(
+			list_T *list = ltv->vval.v_list;
+
+			// push the next item from the list
+			++idxtv->vval.v_number;
+			if (list == NULL
+				       || idxtv->vval.v_number >= list->lv_len)
+			{
+			    // past the end of the list, jump to "endfor"
+			    ectx.ec_iidx = iptr->isn_arg.forloop.for_end;
+			    may_restore_cmdmod(&funclocal);
+			}
+			else if (list->lv_first == &range_list_item)
+			{
+			    // non-materialized range() list
+			    tv = STACK_TV_BOT(0);
+			    tv->v_type = VAR_NUMBER;
+			    tv->v_lock = 0;
+			    tv->vval.v_number = list_find_nr(
 					     list, idxtv->vval.v_number, NULL);
-			++ectx.ec_stack.ga_len;
+			    ++ectx.ec_stack.ga_len;
+			}
+			else
+			{
+			    listitem_T *li = list_find(list,
+							 idxtv->vval.v_number);
+
+			    copy_tv(&li->li_tv, STACK_TV_BOT(0));
+			    ++ectx.ec_stack.ga_len;
+			}
+		    }
+		    else if (ltv->v_type == VAR_STRING)
+		    {
+			char_u	*str = ltv->vval.v_string;
+			int	len = str == NULL ? 0 : (int)STRLEN(str);
+
+			// Push the next character from the string.  The index
+			// is for the last byte of the previous character.
+			++idxtv->vval.v_number;
+			if (idxtv->vval.v_number >= len)
+			{
+			    // past the end of the string, jump to "endfor"
+			    ectx.ec_iidx = iptr->isn_arg.forloop.for_end;
+			    may_restore_cmdmod(&funclocal);
+			}
+			else
+			{
+			    int	clen = mb_ptr2len(str + idxtv->vval.v_number);
+
+			    tv = STACK_TV_BOT(0);
+			    tv->v_type = VAR_STRING;
+			    tv->vval.v_string = vim_strnsave(
+					     str + idxtv->vval.v_number, clen);
+			    ++ectx.ec_stack.ga_len;
+			    idxtv->vval.v_number += clen - 1;
+			}
 		    }
 		    else
 		    {
-			listitem_T *li = list_find(list, idxtv->vval.v_number);
-
-			copy_tv(&li->li_tv, STACK_TV_BOT(0));
-			++ectx.ec_stack.ga_len;
+			// TODO: support Blob
+			semsg(_(e_for_loop_on_str_not_supported),
+						    vartype_name(ltv->v_type));
+			goto failed;
 		    }
 		}
 		break;