kiloz

commit 461803ad76e2698b9bd468aa81ed0ad93f099669
parent 5702e585fb5ef422e82aecc0653aeaa2c21da572
Author: Martin Ashby <martin@ashbysoft.com>
Date:   Sat, 13 Jan 2024 20:50:10 +0000

Handle some edge cases with cursor movement
Make it match sublime text :)

Diffstat:
M
src/main.zig
 | 
48
++++++++++++++++++++++++++++++++++++++----------

1 file changed, 38 insertions(+), 10 deletions(-)
diff --git a/src/main.zig b/src/main.zig
@@ -39,6 +39,7 @@ const EditorState = struct {
     screenrows: usize = 0,
     screencols: usize = 0,
     cx: usize = 0,
+    cx_t: usize = 0,
     cy: usize = 0,
     rowoff: usize = 0,
     coloff: usize = 0,
@@ -307,41 +308,68 @@ fn editorProcessKeyPress(es: *EditorState) !void {
         },
         .virt => |v| {
             switch (v) {
-                .ARROW_UP, .ARROW_DOWN, .ARROW_LEFT, .ARROW_RIGHT, .PAGE_UP, .PAGE_DOWN, .HOME, .END => try editorMoveCursor(key, es),
+                .ARROW_UP, .ARROW_DOWN, .ARROW_LEFT, .ARROW_RIGHT, .PAGE_UP, .PAGE_DOWN, .HOME, .END => editorMoveCursor(key, es),
                 else => {},
             }
         },
     }
 }
 
-fn editorMoveCursor(key: editorKey, es: *EditorState) !void {
+fn editorVMove(dir: enum{up,down}, n: usize, es: *EditorState) void {
+    es.cy = switch (dir) {
+        .up => std.math.sub(usize, es.cy, n) catch 0,
+        .down => std.math.clamp(es.cy+n, 0, es.erow.len-1),
+    };
+}
+
+fn editorMoveCursor(key: editorKey, es: *EditorState) void {
     switch (key.virt) {
         .ARROW_UP => {
-            if (es.cy > 0) es.cy -= 1;
+            editorVMove(.up, 1, es);
         },
         .ARROW_DOWN => {
-            if (es.cy < es.erow.len) es.cy += 1;
+            editorVMove(.down, 1, es);
         },
         .ARROW_LEFT => {
-            if (es.cx > 0) es.cx -= 1;
+            if (es.cx_t == 0) {
+                if (es.cy > 0) {
+                    es.cy -= 1;
+                    es.cx_t = es.erow[es.cy].len;
+                }
+            } else {
+                if (es.cx_t == std.math.maxInt(usize)) {
+                    es.cx_t = es.erow[es.cy].len-1;
+                } else {
+                    es.cx_t -= 1;
+                }
+            }
         },
         .ARROW_RIGHT => {
-            es.cx += 1;
+            if (es.cx_t >= es.erow[es.cy].len) {
+                if (es.cy < (es.erow.len-1)) {
+                    es.cy += 1;
+                    es.cx_t = 0;
+                }
+            } else {
+                es.cx_t += 1;
+            }
         },
         .PAGE_UP => {
-            es.cy = std.math.sub(usize, es.cy, es.screenrows) catch 0;
+            editorVMove(.up, es.screenrows, es);
         },
         .PAGE_DOWN => {
-            es.cy = @min(es.cy+es.screenrows, es.erow.len-1);
+            editorVMove(.down, es.screenrows, es);
         },
         .HOME => {
-            es.cx = 0;
+            es.cx_t = 0;
         },
         .END => {
-            es.cx = es.screencols-1;
+            es.cx_t = std.math.maxInt(usize);
         },
         else => {},
     }
+
+    es.cx = std.math.clamp(es.cx_t, 0, es.erow[es.cy].len);
 }
 
 //// Init