patch 8.1.1256: cannot navigate through errors relative to the cursor

Problem:    Cannot navigate through errors relative to the cursor.
Solution:   Add :cabove, :cbelow, :labove and :lbelow. (Yegappan Lakshmanan,
            closes #4316)

runtime/doc/index.txt

@@ -1188,11 +1188,13 @@ tag		command		action ~
 |:cNfile|	:cNf[ile]	go to last error in previous file
 |:cabbrev|	:ca[bbrev]	like ":abbreviate" but for Command-line mode
 |:cabclear|	:cabc[lear]	clear all abbreviations for Command-line mode
+|:cabove|	:cabo[ve]	go to error above current line
 |:caddbuffer|	:cad[dbuffer]	add errors from buffer
 |:caddexpr|	:cadde[xpr]	add errors from expr
 |:caddfile|	:caddf[ile]	add error message to current quickfix list
 |:call|		:cal[l]		call a function
 |:catch|	:cat[ch]	part of a :try command
+|:cbelow|	:cbe[low]	got to error below current line
 |:cbottom|	:cbo[ttom]	scroll to the bottom of the quickfix window
 |:cbuffer|	:cb[uffer]	parse error messages and jump to first error
 |:cc|		:cc		go to specific error
@@ -1350,12 +1352,14 @@ tag		command		action ~
 |:lNext|	:lN[ext]	go to previous entry in location list
 |:lNfile|	:lNf[ile]	go to last entry in previous file
 |:list|		:l[ist]		print lines
+|:labove|	:lab[ove]	go to location above current line
 |:laddexpr|	:lad[dexpr]	add locations from expr
 |:laddbuffer|	:laddb[uffer]	add locations from buffer
 |:laddfile|	:laddf[ile]	add locations to current location list
 |:last|		:la[st]		go to the last file in the argument list
 |:language|	:lan[guage]	set the language (locale)
 |:later|	:lat[er]	go to newer change, redo
+|:lbelow|	:lbe[low]	go to location below current line
 |:lbottom|	:lbo[ttom]	scroll to the bottom of the location window
 |:lbuffer|	:lb[uffer]	parse locations and jump to first location
 |:lcd|		:lc[d]		change directory locally

runtime/doc/quickfix.txt

@@ -123,6 +123,36 @@ processing a quickfix or location list command, it will be aborted.
 			list for the current window is used instead of the
 			quickfix list.
 
+							*:cabo* *:cabove*
+:[count]cabo[ve]	Go to the [count] error above the current line in the
+			current buffer.  If [count] is omitted, then 1 is
+			used.  If there are no errors, then an error message
+			is displayed.  Assumes that the entries in a quickfix
+			list are sorted by their buffer number and line
+			number. If there are multiple errors on the same line,
+			then only the first entry is used.  If [count] exceeds
+			the number of entries above the current line, then the
+			first error in the file is selected.
+
+							*:lab* *:labove*
+:[count]lab[ove]	Same as ":cabove", except the location list for the
+			current window is used instead of the quickfix list.
+
+							*:cbe* *:cbelow*
+:[count]cbe[low]	Go to the [count] error below the current line in the
+			current buffer.  If [count] is omitted, then 1 is
+			used.  If there are no errors, then an error message
+			is displayed.  Assumes that the entries in a quickfix
+			list are sorted by their buffer number and line
+			number.  If there are multiple errors on the same
+			line, then only the first entry is used.  If [count]
+			exceeds the number of entries below the current line,
+			then the last error in the file is selected.
+
+							*:lbe* *:lbelow*
+:[count]lbe[low]	Same as ":cbelow", except the location list for the
+			current window is used instead of the quickfix list.
+
 							*:cnf* *:cnfile*
 :[count]cnf[ile][!]	Display the first error in the [count] next file in
 			the list that includes a file name.  If there are no

src/ex_cmdidxs.h

@@ -8,29 +8,29 @@ static const unsigned short cmdidxs1[26] =
   /* a */ 0,
   /* b */ 19,
   /* c */ 42,
-  /* d */ 103,
-  /* e */ 125,
-  /* f */ 145,
-  /* g */ 161,
-  /* h */ 167,
-  /* i */ 176,
-  /* j */ 194,
-  /* k */ 196,
-  /* l */ 201,
-  /* m */ 259,
-  /* n */ 277,
-  /* o */ 297,
-  /* p */ 309,
-  /* q */ 348,
-  /* r */ 351,
-  /* s */ 371,
-  /* t */ 439,
-  /* u */ 484,
-  /* v */ 495,
-  /* w */ 513,
-  /* x */ 527,
-  /* y */ 536,
-  /* z */ 537
+  /* d */ 105,
+  /* e */ 127,
+  /* f */ 147,
+  /* g */ 163,
+  /* h */ 169,
+  /* i */ 178,
+  /* j */ 196,
+  /* k */ 198,
+  /* l */ 203,
+  /* m */ 263,
+  /* n */ 281,
+  /* o */ 301,
+  /* p */ 313,
+  /* q */ 352,
+  /* r */ 355,
+  /* s */ 375,
+  /* t */ 443,
+  /* u */ 488,
+  /* v */ 499,
+  /* w */ 517,
+  /* x */ 531,
+  /* y */ 540,
+  /* z */ 541
 };
 
 /*
@@ -43,7 +43,7 @@ static const unsigned char cmdidxs2[26][26] =
 { /*         a   b   c   d   e   f   g   h   i   j   k   l   m   n   o   p   q   r   s   t   u   v   w   x   y   z */
   /* a */ {  0,  1,  0,  0,  0,  0,  0,  0,  0,  0,  0,  4,  5,  6,  0,  0,  0,  7, 15,  0, 16,  0,  0,  0,  0,  0 },
   /* b */ {  2,  0,  0,  4,  5,  7,  0,  0,  0,  0,  0,  8,  9, 10, 11, 12,  0, 13,  0,  0,  0,  0, 22,  0,  0,  0 },
-  /* c */ {  3, 10, 12, 14, 16, 18, 21,  0,  0,  0,  0, 29, 33, 36, 42, 51, 53, 54, 55,  0, 57,  0, 60,  0,  0,  0 },
+  /* c */ {  3, 11, 14, 16, 18, 20, 23,  0,  0,  0,  0, 31, 35, 38, 44, 53, 55, 56, 57,  0, 59,  0, 62,  0,  0,  0 },
   /* d */ {  0,  0,  0,  0,  0,  0,  0,  0,  6, 15,  0, 16,  0,  0, 17,  0,  0, 19, 20,  0,  0,  0,  0,  0,  0,  0 },
   /* e */ {  1,  0,  2,  0,  0,  0,  0,  0,  0,  0,  0,  7,  9, 10,  0,  0,  0,  0,  0,  0,  0,  0,  0, 16,  0,  0 },
   /* f */ {  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  9,  0,  0,  0,  0,  0, 15,  0,  0,  0,  0,  0 },
@@ -52,7 +52,7 @@ static const unsigned char cmdidxs2[26][26] =
   /* i */ {  1,  0,  0,  0,  0,  3,  0,  0,  0,  4,  0,  5,  6,  0,  0,  0,  0,  0, 13,  0, 15,  0,  0,  0,  0,  0 },
   /* j */ {  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  1,  0,  0,  0,  0,  0 },
   /* k */ {  0,  0,  0,  0,  1,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0 },
-  /* l */ {  3,  9, 11, 15, 16, 20, 23, 28,  0,  0,  0, 30, 33, 36, 40, 46,  0, 48, 57, 49, 50, 54, 56,  0,  0,  0 },
+  /* l */ {  3, 10, 13, 17, 18, 22, 25, 30,  0,  0,  0, 32, 35, 38, 42, 48,  0, 50, 59, 51, 52, 56, 58,  0,  0,  0 },
   /* m */ {  1,  0,  0,  0,  7,  0,  0,  0,  0,  0, 10,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0, 16 },
   /* n */ {  0,  1,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  5,  8, 10,  0,  0,  0,  0,  0, 17,  0,  0,  0,  0,  0 },
   /* o */ {  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  1,  2,  5,  0,  0,  0,  0,  0,  0,  9,  0, 11,  0,  0,  0 },
@@ -69,4 +69,4 @@ static const unsigned char cmdidxs2[26][26] =
   /* z */ {  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0 }
 };
 
-static const int command_count = 550;
+static const int command_count = 554;

src/ex_cmds.h

@@ -252,6 +252,9 @@ EX(CMD_cabbrev,		"cabbrev",	ex_abbreviate,
 EX(CMD_cabclear,	"cabclear",	ex_abclear,
 			EXTRA|TRLBAR|CMDWIN,
 			ADDR_NONE),
+EX(CMD_cabove,		"cabove",	ex_cbelow,
+			RANGE|TRLBAR,
+			ADDR_OTHER),
 EX(CMD_caddbuffer,	"caddbuffer",	ex_cbuffer,
 			RANGE|WORD1|TRLBAR,
 			ADDR_OTHER),
@@ -270,6 +273,9 @@ EX(CMD_catch,		"catch",	ex_catch,
 EX(CMD_cbuffer,		"cbuffer",	ex_cbuffer,
 			BANG|RANGE|WORD1|TRLBAR,
 			ADDR_OTHER),
+EX(CMD_cbelow,		"cbelow",	ex_cbelow,
+			RANGE|TRLBAR,
+			ADDR_OTHER),
 EX(CMD_cbottom,		"cbottom",	ex_cbottom,
 			TRLBAR,
 			ADDR_NONE),
@@ -726,6 +732,9 @@ EX(CMD_lNfile,		"lNfile",	ex_cnext,
 EX(CMD_last,		"last",		ex_last,
 			EXTRA|BANG|EDITCMD|ARGOPT|TRLBAR,
 			ADDR_NONE),
+EX(CMD_labove,		"labove",	ex_cbelow,
+			RANGE|TRLBAR,
+			ADDR_OTHER),
 EX(CMD_language,	"language",	ex_language,
 			EXTRA|TRLBAR|CMDWIN,
 			ADDR_NONE),
@@ -744,6 +753,9 @@ EX(CMD_later,		"later",	ex_later,
 EX(CMD_lbuffer,		"lbuffer",	ex_cbuffer,
 			BANG|RANGE|WORD1|TRLBAR,
 			ADDR_OTHER),
+EX(CMD_lbelow,		"lbelow",	ex_cbelow,
+			RANGE|TRLBAR,
+			ADDR_OTHER),
 EX(CMD_lbottom,		"lbottom",	ex_cbottom,
 			TRLBAR,
 			ADDR_NONE),

src/ex_docmd.c

@@ -56,6 +56,7 @@ static int	getargopt(exarg_T *eap);
 # define ex_cbuffer		ex_ni
 # define ex_cc			ex_ni
 # define ex_cnext		ex_ni
+# define ex_cbelow		ex_ni
 # define ex_cfile		ex_ni
 # define qf_list		ex_ni
 # define qf_age			ex_ni

src/proto/quickfix.pro

@@ -23,6 +23,7 @@ int qf_get_cur_idx(exarg_T *eap);
 int qf_get_cur_valid_idx(exarg_T *eap);
 void ex_cc(exarg_T *eap);
 void ex_cnext(exarg_T *eap);
+void ex_cbelow(exarg_T *eap);
 void ex_cfile(exarg_T *eap);
 void ex_vimgrep(exarg_T *eap);
 int get_errorlist(qf_info_T *qi_arg, win_T *wp, int qf_idx, list_T *list);