add position marks (Ma/g'a)

5 files changed, 88 insertions, 11 deletions

diff --git a/TODO b/TODO
index 1375028..ecd2a35 100644
--- a/TODO
+++ b/TODO
@@ -1,6 +1,7 @@
 + optimize redraws (redraw only the modified rectangle)
 - add screen geometry option (-g 25x80?)
 - (?)maybe move "text" mode to "t"
+- implement trapezium
 - implement ellipse
 - (?) filled box (B)
 - (?) manage filled box character (as for other styles)
@@ -13,6 +14,7 @@
 - allow scrolling (both vertical and horizontal)
 - catch SIGWINCH and react appropriately (after scrolling is 
   enabled)
+* add position marks (Ma / g'a)
 * implement comment (#: ignore everything until the end of the line)
 * implement parallelogram mode (z/Z)
 * fix bug in reading commands from files
diff --git a/gramscii.1 b/gramscii.1
index 3370c24..b130530 100644
--- a/gramscii.1
+++ b/gramscii.1
@@ -86,6 +86,17 @@ command).
 Load (edit) an existing file from disk, discarding any change to the
 current screen.
 .TP 5m
+.BI M a
+Mark (label) the current cursor position as 'a'. The label 'a' must be
+one of the 26 ASCII alphabetic characters. The cursor can be moved to a
+previously marked position using the global positioning command
+.B g
+(see below). Position marks are case-insensitive, meaning that both 
+.I 'c'
+and
+.I 'C'
+indicate the same mark.
+.TP 5m
 .BI N
 Start a new empty screen. If the current screen has been modified since
 the last
@@ -178,11 +189,13 @@ units at a time (defaults to 5, change LONG_STEP in config.h as you
 wish).
 .TP 5m
 .BI g
-Initiate a global positioning command (go). These are two-letter
-commands starting with a
+Initiate a global positioning command (go). These are two- or
+three-letter commands starting with a
 .BI g
-and followed by a direction command or by a character that indicates a
-global position, namely:
+and followed by a direction command, or by a character that indicates a
+global position, or by a valid position mark previously defined with 
+.B M
+and preceded by a single quote. In particular:
 .RS
 .TP 5m
 .BI h
@@ -205,9 +218,24 @@ move the cursor to the bottom-right corner of the screen
 .TP 5m
 .BI m
 move the cursor to the middle of the screen.
+.TP 5m
+.BI 'a
+(single-quote followed by a character) move the cursor to the position
+previously marked (labelled) with character
+.BI 'a'
+by the command
+.B M
+(mark). The character 'a' must be one of the 26 ASCII alphabetic
+characters. Notice that position marks are case-insensitive, so the two
+commands:
+.B g'b
+and
+.B g'B
+move the cursor to the position mark associated to the letter 'b', if it
+exists.
 .PP
-For instance, if you want to move the cursor to the first row of the
-current column, you would use the two-letter command 
+If you want to move the cursor to the first row of the current
+column, you could use the two-letter command 
 .B gk 
 (which can be read as "go-up"). Similarly, the command
 .B gh
@@ -227,13 +255,13 @@ is equivalent to
 ).
 .PP
 Global positioning commands are available in 
-.B box, arrow, visual,
+.B box, arrow, visual, parallelogram, 
 and 
 .B erase
 mode. Notice that
-.B gg, gG, 
-and 
-.B gm, 
+.B gg, gG, gm 
+and moves to position marks like
+.B g'b, 
 are not available in 
 .B arrow
 mode.
diff --git a/gramscii.c b/gramscii.c
index 977a8cb..5c893fe 100644
--- a/gramscii.c
+++ b/gramscii.c
@@ -142,6 +142,9 @@ void commands(FILE *fc){
 					mode = REM;
 					get_comment(fc);
 					break;
+				case 'M':
+					mark_pos(fc);
+					break;
 				case 'q':
 					check_modified(fc);/** FALLTHROUGH **/
 				case 'Q':
diff --git a/gramscii.h b/gramscii.h
index 8aec939..c2b9170 100644
--- a/gramscii.h
+++ b/gramscii.h
@@ -90,6 +90,11 @@ typedef struct{
 	line_t *l;
 } lineset_t;
 
+typedef struct{
+	int x;
+	int y;
+} pos_t;
+
 
 /** MACROS **/
 
@@ -105,6 +110,9 @@ lineset_t screen; /* what is visualised */
 lineset_t cutbuf; /* cut/paste buffer */
 lineset_t *undo;  /* undo list */
 
+pos_t marks[26]; /* position marks */
+char mark_map[26]; /* marks map */
+
 int undo_sz;/* allocated size of undo list*/
 int undo_cur;/* undo position */
 int undo_lst;/* last valid undo position */
@@ -175,6 +183,7 @@ void crop_to_nonblank();
 void crop_to_rect();
 void erase_blank_lines(int y1, int y2);
 int _isblank(int c);
+void mark_pos(FILE *fc);
 /**/
 
 /** drawing-related functions **/
diff --git a/screen.c b/screen.c
index 28d2318..0ef1f69 100644
--- a/screen.c
+++ b/screen.c
@@ -301,6 +301,24 @@ void handle_goto(FILE *fc, char global){
 				go_to(MIDDLE);
 			} else step = 0;
 			break;
+		case '\'':
+			c = tolower(fgetc(fc));
+			if (global) {
+				dir = DIR_N;
+				if (isalpha(c) && mark_map[c - 'a']){
+					x = marks[c - 'a'].x;
+					y = marks[c - 'a'].y;
+#ifdef DEBUG
+					fprintf(stderr, "going to valid mark '%c' (%d, %d)\n", c, x, y);
+#endif
+				}
+#ifdef DEBUG
+				else 
+					fprintf(stderr, "invalid mark '%c'\n", c);
+#endif
+			} else step = 0;
+			break;
+
 	}
 
 #ifdef DEBUG
@@ -435,20 +453,23 @@ void init_screen(){
 	for (i=0; i<HEIGHT; i++){
 		alloc_line(&(screen.l[i]));
 	}
+	/* init markers */
 	hlines_sz= sizeof(hlines) -1;
 	vlines_sz= sizeof(vlines) -1;
 	corners_sz = sizeof(corners) -1;
 	stmarks_sz = sizeof(st_marks) - 1;
 	endmarks_sz = sizeof(st_marks) - 1;
 	reset_styles();
+	/* init undo ring */	
 	cutbuf.sz = 0;
 	cutbuf.l = NULL;
 	cutbuf.num = 0;
-	
 	undo = NULL;
 	undo_sz = 0;
 	undo_cur = -2;
 	undo_lst = -2;
+	/* init pos marks */
+	memset(mark_map, 0, 26 * sizeof(char));
 }
 
 void find_nonblank_rect(int *x1, int *y1, int *x2, int *y2){
@@ -507,4 +528,18 @@ void crop_to_nonblank(){
 	redraw();
 }
 
+/** position marks **/
 
+void mark_pos(FILE *fc){
+
+	char c;
+	c = tolower(fgetc(fc));
+	if (isalpha(c)){
+		marks[c - 'a'].x = x;
+		marks[c - 'a'].y = y;
+		mark_map[c - 'a'] = 1;
+#ifdef DEBUG
+		fprintf(stderr, "marking pos (%d, %d) as '%c'\n", x, y, c);
+#endif
+	}
+}