Merge pull request #631 from mitchellh/xt-cuf

xterm audit: CUF, CUP, HPA, VPA, HPR, VPR

src/terminal/Terminal.zig

@@ -975,9 +975,9 @@ pub fn setCursorPos(self: *Terminal, row_req: usize, col_req: usize) void {
         x_max: usize,
         y_max: usize,
     } = if (self.modes.get(.origin)) .{
-        .x_offset = 0, // TODO: left/right margins
+        .x_offset = self.scrolling_region.left,
         .y_offset = self.scrolling_region.top,
-        .x_max = self.cols, // TODO: left/right margins
+        .x_max = self.scrolling_region.right + 1, // We need this 1-indexed
         .y_max = self.scrolling_region.bottom + 1, // We need this 1-indexed
     } else .{
         .x_max = self.cols,
@@ -986,7 +986,7 @@ pub fn setCursorPos(self: *Terminal, row_req: usize, col_req: usize) void {
 
     const row = if (row_req == 0) 1 else row_req;
     const col = if (col_req == 0) 1 else col_req;
-    self.screen.cursor.x = @min(params.x_max, col) -| 1;
+    self.screen.cursor.x = @min(params.x_max, col + params.x_offset) -| 1;
     self.screen.cursor.y = @min(params.y_max, row + params.y_offset) -| 1;
     // log.info("set cursor position: col={} row={}", .{ self.screen.cursor.x, self.screen.cursor.y });
 
@@ -994,34 +994,6 @@ pub fn setCursorPos(self: *Terminal, row_req: usize, col_req: usize) void {
     self.screen.cursor.pending_wrap = false;
 }
 
-/// Move the cursor to column `col_req` (1-indexed) without modifying the row.
-/// If `col_req` is 0, it is changed to 1. If `col_req` is greater than the
-/// total number of columns, it is set to the right-most column.
-///
-/// If cursor origin mode is set, the cursor row will be set inside the
-/// current scroll region.
-pub fn setCursorColAbsolute(self: *Terminal, col_req: usize) void {
-    const tracy = trace(@src());
-    defer tracy.end();
-
-    // TODO: test
-
-    // TODO
-    if (self.modes.get(.origin)) {
-        log.err("setCursorColAbsolute: cursor origin mode handling not implemented yet", .{});
-        return;
-    }
-
-    if (self.status_display != .main) {
-        log.err("setCursorColAbsolute: not implemented on status display", .{});
-        return; // TODO
-    }
-
-    const col = if (col_req == 0) 1 else col_req;
-    self.screen.cursor.x = @min(self.cols, col) - 1;
-    self.screen.cursor.pending_wrap = false;
-}
-
 /// Erase the display.
 pub fn eraseDisplay(
     self: *Terminal,
@@ -1439,16 +1411,21 @@ pub fn cursorLeft(self: *Terminal, count_req: usize) void {
 /// maximum move distance then it is internally adjusted to the maximum.
 /// This sequence will not scroll the screen or scroll region. If amount is
 /// 0, adjust it to 1.
-/// TODO: test
+pub fn cursorRight(self: *Terminal, count_req: usize) void {
-pub fn cursorRight(self: *Terminal, count: usize) void {
     const tracy = trace(@src());
     defer tracy.end();
 
-    self.screen.cursor.x += if (count == 0) 1 else count;
+    // Always resets pending wrap
     self.screen.cursor.pending_wrap = false;
-    if (self.screen.cursor.x >= self.cols) {
+
-        self.screen.cursor.x = self.cols - 1;
+    // The max the cursor can move to depends where the cursor currently is
-    }
+    const max = if (self.screen.cursor.x <= self.scrolling_region.right)
+        self.scrolling_region.right
+    else
+        self.cols - 1;
+
+    const count = @max(count_req, 1);
+    self.screen.cursor.x = @min(max, self.screen.cursor.x +| count);
 }
 
 /// Move the cursor down amount lines. If amount is greater than the maximum
@@ -2417,7 +2394,98 @@ test "Terminal: horizontal tabs with left margin in origin mode" {
     }
 }
 
-test "Terminal: setCursorPosition" {
+test "Terminal: cursorPos resets wrap" {
+    const alloc = testing.allocator;
+    var t = try init(alloc, 5, 5);
+    defer t.deinit(alloc);
+
+    for ("ABCDE") |c| try t.print(c);
+    try testing.expect(t.screen.cursor.pending_wrap);
+    t.setCursorPos(1, 1);
+    try testing.expect(!t.screen.cursor.pending_wrap);
+    try t.print('X');
+
+    {
+        var str = try t.plainString(testing.allocator);
+        defer testing.allocator.free(str);
+        try testing.expectEqualStrings("XBCDE", str);
+    }
+}
+
+test "Terminal: cursorPos off the screen" {
+    const alloc = testing.allocator;
+    var t = try init(alloc, 5, 5);
+    defer t.deinit(alloc);
+
+    t.setCursorPos(500, 500);
+    try t.print('X');
+
+    {
+        var str = try t.plainString(testing.allocator);
+        defer testing.allocator.free(str);
+        try testing.expectEqualStrings("\n\n\n\n    X", str);
+    }
+}
+
+test "Terminal: cursorPos relative to origin" {
+    const alloc = testing.allocator;
+    var t = try init(alloc, 5, 5);
+    defer t.deinit(alloc);
+
+    t.scrolling_region.top = 2;
+    t.scrolling_region.bottom = 3;
+    t.modes.set(.origin, true);
+    t.setCursorPos(1, 1);
+    try t.print('X');
+
+    {
+        var str = try t.plainString(testing.allocator);
+        defer testing.allocator.free(str);
+        try testing.expectEqualStrings("\n\nX", str);
+    }
+}
+
+test "Terminal: cursorPos relative to origin with left/right" {
+    const alloc = testing.allocator;
+    var t = try init(alloc, 5, 5);
+    defer t.deinit(alloc);
+
+    t.scrolling_region.top = 2;
+    t.scrolling_region.bottom = 3;
+    t.scrolling_region.left = 2;
+    t.scrolling_region.right = 4;
+    t.modes.set(.origin, true);
+    t.setCursorPos(1, 1);
+    try t.print('X');
+
+    {
+        var str = try t.plainString(testing.allocator);
+        defer testing.allocator.free(str);
+        try testing.expectEqualStrings("\n\n  X", str);
+    }
+}
+
+test "Terminal: cursorPos limits with full scroll region" {
+    const alloc = testing.allocator;
+    var t = try init(alloc, 5, 5);
+    defer t.deinit(alloc);
+
+    t.scrolling_region.top = 2;
+    t.scrolling_region.bottom = 3;
+    t.scrolling_region.left = 2;
+    t.scrolling_region.right = 4;
+    t.modes.set(.origin, true);
+    t.setCursorPos(500, 500);
+    try t.print('X');
+
+    {
+        var str = try t.plainString(testing.allocator);
+        defer testing.allocator.free(str);
+        try testing.expectEqualStrings("\n\n\n    X", str);
+    }
+}
+
+test "Terminal: setCursorPos (original test)" {
     var t = try init(testing.allocator, 80, 80);
     defer t.deinit(testing.allocator);
 
@@ -3509,18 +3577,6 @@ test "Terminal: eraseChars resets wrap" {
     }
 }
 
-test "Terminal: setCursorColAbsolute resets pending wrap" {
-    const alloc = testing.allocator;
-    var t = try init(alloc, 5, 5);
-    defer t.deinit(alloc);
-
-    for ("ABCDE") |c| try t.print(c);
-    try testing.expect(t.screen.cursor.pending_wrap);
-    t.setCursorColAbsolute(1);
-    try testing.expect(!t.screen.cursor.pending_wrap);
-    try testing.expectEqual(@as(usize, 0), t.screen.cursor.x);
-}
-
 // https://github.com/mitchellh/ghostty/issues/272
 // This is also tested in depth in screen resize tests but I want to keep
 // this test around to ensure we don't regress at multiple layers.
@@ -3624,10 +3680,10 @@ test "Terminal: eraseLine protected right" {
     defer t.deinit(alloc);
 
     for ("12345678") |c| try t.print(c);
-    t.setCursorColAbsolute(6);
+    t.setCursorPos(t.screen.cursor.y + 1, 6);
     t.setProtectedMode(.dec);
     try t.print('X');
-    t.setCursorColAbsolute(4);
+    t.setCursorPos(t.screen.cursor.y + 1, 4);
     t.eraseLine(.right, true);
 
     {
@@ -3643,10 +3699,10 @@ test "Terminal: eraseLine protected left" {
     defer t.deinit(alloc);
 
     for ("123456789") |c| try t.print(c);
-    t.setCursorColAbsolute(6);
+    t.setCursorPos(t.screen.cursor.y + 1, 6);
     t.setProtectedMode(.dec);
     try t.print('X');
-    t.setCursorColAbsolute(8);
+    t.setCursorPos(t.screen.cursor.y + 1, 8);
     t.eraseLine(.left, true);
 
     {
@@ -3662,10 +3718,10 @@ test "Terminal: eraseLine protected complete" {
     defer t.deinit(alloc);
 
     for ("123456789") |c| try t.print(c);
-    t.setCursorColAbsolute(6);
+    t.setCursorPos(t.screen.cursor.y + 1, 6);
     t.setProtectedMode(.dec);
     try t.print('X');
-    t.setCursorColAbsolute(8);
+    t.setCursorPos(t.screen.cursor.y + 1, 8);
     t.eraseLine(.complete, true);
 
     {
@@ -3684,10 +3740,10 @@ test "Terminal: eraseDisplay protected complete" {
     t.carriageReturn();
     try t.linefeed();
     for ("123456789") |c| try t.print(c);
-    t.setCursorColAbsolute(6);
+    t.setCursorPos(t.screen.cursor.y + 1, 6);
     t.setProtectedMode(.dec);
     try t.print('X');
-    t.setCursorColAbsolute(4);
+    t.setCursorPos(t.screen.cursor.y + 1, 4);
     t.eraseDisplay(alloc, .complete, true);
 
     {
@@ -3706,10 +3762,10 @@ test "Terminal: eraseDisplay protected below" {
     t.carriageReturn();
     try t.linefeed();
     for ("123456789") |c| try t.print(c);
-    t.setCursorColAbsolute(6);
+    t.setCursorPos(t.screen.cursor.y + 1, 6);
     t.setProtectedMode(.dec);
     try t.print('X');
-    t.setCursorColAbsolute(4);
+    t.setCursorPos(t.screen.cursor.y + 1, 4);
     t.eraseDisplay(alloc, .below, true);
 
     {
@@ -3728,10 +3784,10 @@ test "Terminal: eraseDisplay protected above" {
     t.carriageReturn();
     try t.linefeed();
     for ("123456789") |c| try t.print(c);
-    t.setCursorColAbsolute(6);
+    t.setCursorPos(t.screen.cursor.y + 1, 6);
     t.setProtectedMode(.dec);
     try t.print('X');
-    t.setCursorColAbsolute(8);
+    t.setCursorPos(t.screen.cursor.y + 1, 8);
     t.eraseDisplay(alloc, .above, true);
 
     {
@@ -4044,3 +4100,69 @@ test "Terminal: cursorUp resets wrap" {
         try testing.expectEqualStrings("ABCDX", str);
     }
 }
+
+test "Terminal: cursorRight resets wrap" {
+    const alloc = testing.allocator;
+    var t = try init(alloc, 5, 5);
+    defer t.deinit(alloc);
+
+    for ("ABCDE") |c| try t.print(c);
+    try testing.expect(t.screen.cursor.pending_wrap);
+    t.cursorRight(1);
+    try testing.expect(!t.screen.cursor.pending_wrap);
+    try t.print('X');
+
+    {
+        var str = try t.plainString(testing.allocator);
+        defer testing.allocator.free(str);
+        try testing.expectEqualStrings("ABCDX", str);
+    }
+}
+
+test "Terminal: cursorRight to the edge of screen" {
+    const alloc = testing.allocator;
+    var t = try init(alloc, 5, 5);
+    defer t.deinit(alloc);
+
+    t.cursorRight(100);
+    try t.print('X');
+
+    {
+        var str = try t.plainString(testing.allocator);
+        defer testing.allocator.free(str);
+        try testing.expectEqualStrings("    X", str);
+    }
+}
+
+test "Terminal: cursorRight left of right margin" {
+    const alloc = testing.allocator;
+    var t = try init(alloc, 5, 5);
+    defer t.deinit(alloc);
+
+    t.scrolling_region.right = 2;
+    t.cursorRight(100);
+    try t.print('X');
+
+    {
+        var str = try t.plainString(testing.allocator);
+        defer testing.allocator.free(str);
+        try testing.expectEqualStrings("  X", str);
+    }
+}
+
+test "Terminal: cursorRight right of right margin" {
+    const alloc = testing.allocator;
+    var t = try init(alloc, 5, 5);
+    defer t.deinit(alloc);
+
+    t.scrolling_region.right = 2;
+    t.screen.cursor.x = 3;
+    t.cursorRight(100);
+    try t.print('X');
+
+    {
+        var str = try t.plainString(testing.allocator);
+        defer testing.allocator.free(str);
+        try testing.expectEqualStrings("    X", str);
+    }
+}

src/terminal/stream.zig

@@ -432,6 +432,18 @@ pub fn Stream(comptime Handler: type) type {
                     },
                 ) else log.warn("unimplemented CSI callback: {}", .{action}),
 
+                // HPR - Cursor Horizontal Position Relative
+                'a' => if (@hasDecl(T, "setCursorColRelative")) try self.handler.setCursorColRelative(
+                    switch (action.params.len) {
+                        0 => 1,
+                        1 => action.params[0],
+                        else => {
+                            log.warn("invalid HPR command: {}", .{action});
+                            return;
+                        },
+                    },
+                ) else log.warn("unimplemented CSI callback: {}", .{action}),
+
                 // Repeat Previous Char (REP)
                 'b' => if (@hasDecl(T, "printRepeat")) try self.handler.printRepeat(
                     switch (action.params.len) {
@@ -474,6 +486,18 @@ pub fn Stream(comptime Handler: type) type {
                     },
                 ) else log.warn("unimplemented CSI callback: {}", .{action}),
 
+                // VPR - Cursor Vertical Position Relative
+                'e' => if (@hasDecl(T, "setCursorRowRelative")) try self.handler.setCursorRowRelative(
+                    switch (action.params.len) {
+                        0 => 1,
+                        1 => action.params[0],
+                        else => {
+                            log.warn("invalid VPR command: {}", .{action});
+                            return;
+                        },
+                    },
+                ) else log.warn("unimplemented CSI callback: {}", .{action}),
+
                 // TBC - Tab Clear
                 // TODO: test
                 'g' => if (@hasDecl(T, "tabClear")) try self.handler.tabClear(

src/termio/Exec.zig

@@ -1313,18 +1313,27 @@ const StreamHandler = struct {
     }
 
     pub fn setCursorCol(self: *StreamHandler, col: u16) !void {
-        self.terminal.setCursorColAbsolute(col);
+        self.terminal.setCursorPos(self.terminal.screen.cursor.y + 1, col);
+    }
+
+    pub fn setCursorColRelative(self: *StreamHandler, offset: u16) !void {
+        self.terminal.setCursorPos(
+            self.terminal.screen.cursor.y + 1,
+            self.terminal.screen.cursor.x + 1 + offset,
+        );
     }
 
     pub fn setCursorRow(self: *StreamHandler, row: u16) !void {
-        if (self.terminal.modes.get(.origin)) {
-            // TODO
-            log.err("setCursorRow: unimplemented origin mode handling, misrendering may occur", .{});
-        }
-
         self.terminal.setCursorPos(row, self.terminal.screen.cursor.x + 1);
     }
 
+    pub fn setCursorRowRelative(self: *StreamHandler, offset: u16) !void {
+        self.terminal.setCursorPos(
+            self.terminal.screen.cursor.y + 1 + offset,
+            self.terminal.screen.cursor.x + 1,
+        );
+    }
+
     pub fn setCursorPos(self: *StreamHandler, row: u16, col: u16) !void {
         self.terminal.setCursorPos(row, col);
     }

website/app/vt/cuf/page.mdx

@@ -0,0 +1,83 @@
+import VTSequence from "@/components/VTSequence";
+
+# Cursor Forward (CUF)
+
+<VTSequence sequence={["CSI", "Pn", "C"]} />
+
+Move the cursor `n` cells right.
+
+The parameter `n` must be an integer greater than or equal to 1. If `n` is less than
+or equal to 0, adjust `n` to be 1. If `n` is omitted, `n` defaults to 1.
+
+This sequence always unsets the pending wrap state.
+
+The rightmost boundary the cursor can move to is determined by the current
+cursor column and the [right margin](#TODO). If the cursor begins to the right
+of the right margin, modify the right margin to be the rightmost column
+of the screen for the duration of the sequence. The rightmost column the cursor
+can be on is the right margin.
+
+Move the cursor `n` cells to the right up to and including the rightmost boundary.
+This sequence never wraps or modifies cell content. This sequence is not affected
+by any terminal modes.
+
+## Validation
+
+### CUF V-1: Pending Wrap is Unset
+
+```bash
+cols=$(tput cols)
+printf "\033[${cols}G" # move to last column
+printf "A" # set pending wrap state
+printf "\033[C" # move forward one
+printf "XYZ"
+```
+
+```
+|_________X|
+|YZ________|
+```
+
+### CUF V-2: Rightmost Boundary with Reverse Wrap Disabled
+
+```bash
+printf "A"
+printf "\033[500C" # forward larger than screen width
+printf "B"
+```
+
+```
+|A________Bc
+```
+
+### CUF V-3: Left of the Right Margin
+
+```bash
+printf "\033[1;1H" # move to top-left
+printf "\033[0J" # clear screen
+printf "\033[?69h" # enable left/right margins
+printf "\033[3;5s" # scroll region left/right
+printf "\033[1G" # move to left
+printf "\033[500C" # forward larger than screen width
+printf "X"
+```
+
+```
+|____X_____|
+```
+
+### CUF V-4: Right of the Right Margin
+
+```bash
+printf "\033[1;1H" # move to top-left
+printf "\033[0J" # clear screen
+printf "\033[?69h" # enable left/right margins
+printf "\033[3;5s" # scroll region left/right
+printf "\033[6G" # move to right of margin
+printf "\033[500C" # forward larger than screen width
+printf "X"
+```
+
+```
+|_________X|
+```

website/app/vt/cup/page.mdx

@@ -0,0 +1,127 @@
+import VTSequence from "@/components/VTSequence";
+
+# Cursor Position (CUP)
+
+<VTSequence sequence={["CSI", "Py", ";", "Px", "H"]} />
+
+Move the cursor to row `y` and column `x`.
+
+The parameters `y` and `x` must be integers greater than or equal to 1.
+If either is less than or equal to 0, adjust that parameter to be 1.
+
+The values `y` and `x` are both one-based. For example, the top row is row 1
+and the leftmost column on the screen is column 1.
+
+This sequence always unsets the pending wrap state.
+
+If [origin mode](#TODO) is **NOT** set, the cursor is moved exactly to the
+row and column specified by `y` and `x`. The maxium value for `y` is the
+bottom row of the screen and the maximum value for `x` is the rightmost
+column of the screen.
+
+If [origin mode](#TODO) is set, the cursor position is set relative
+to the top-left corner of the scroll region. `y = 1` corresponds to
+the [top margin](#TODO) and `x = 1` corresponds to the [left margin](#TODO).
+The maximum value for `y` is the [bottom margin](#TODO) and the maximum
+value for `x` is the [right margin](#TODO).
+
+When origin mode is set, it is impossible set a cursor position using
+this sequence outside the boundaries of the scroll region.
+
+## Validation
+
+### CUP V-1: Normal Usage
+
+```bash
+printf "\033[1;1H" # move to top-left
+printf "\033[0J" # clear screen
+printf "\033[2;3H"
+printf "A"
+```
+
+```
+|__________|
+|__Ac______|
+```
+
+### CUP V-2: Off the Screen
+
+```bash
+printf "\033[1;1H" # move to top-left
+printf "\033[0J" # clear screen
+printf "\033[500;500H"
+printf "A"
+```
+
+```
+|__________|
+|__________|
+|_________Ac
+```
+
+### CUP V-3: Relative to Origin
+
+```bash
+printf "\033[1;1H" # move to top-left
+printf "\033[0J" # clear screen
+printf "\033[2;3r" # scroll region top/bottom
+printf "\033[?6h" # origin mode
+printf "\033[1;1H" # move to top-left
+printf "X"
+```
+
+```
+|__________|
+|X_________|
+```
+
+### CUP V-4: Relative to Origin with Left/Right Margins
+
+```bash
+printf "\033[1;1H" # move to top-left
+printf "\033[0J" # clear screen
+printf "\033[?69h" # enable left/right margins
+printf "\033[3;5s" # scroll region left/right
+printf "\033[2;3r" # scroll region top/bottom
+printf "\033[?6h" # origin mode
+printf "\033[1;1H" # move to top-left
+printf "X"
+```
+
+```
+|__________|
+|__X_______|
+```
+
+### CUP V-5: Limits with Scroll Region and Origin Mode
+
+```bash
+printf "\033[1;1H" # move to top-left
+printf "\033[0J" # clear screen
+printf "\033[?69h" # enable left/right margins
+printf "\033[3;5s" # scroll region left/right
+printf "\033[2;3r" # scroll region top/bottom
+printf "\033[?6h" # origin mode
+printf "\033[500;500H" # move to top-left
+printf "X"
+```
+
+```
+|__________|
+|__________|
+|____X_____|
+```
+
+### CUP V-6: Pending Wrap is Unset
+
+```bash
+cols=$(tput cols)
+printf "\033[${cols}G" # move to last column
+printf "A" # set pending wrap state
+printf "\033[1;1H"
+printf "X"
+```
+
+```
+|Xc_______X|
+```

website/app/vt/hpa/page.mdx

@@ -0,0 +1,14 @@
+import VTSequence from "@/components/VTSequence";
+
+# Horizontal Position Absolute (HPA)
+
+<VTSequence sequence={["CSI", "Px", "`"]} />
+
+This sequence performs [cursor position (CUP)](/vt/cup) with `x` set
+to the parameterized value and `y` set to the current cursor position.
+There is no additional or different behavior for using `HPA`.
+
+Because this invokes `CUP`, the cursor row (`x`) can change if it is
+outside the bounds of the `CUP` operation. For example, if
+[origin mode](#TODO) is set and the current cursor position is outside
+of the scroll region, the row will be adjusted.

website/app/vt/hpr/page.mdx

@@ -0,0 +1,17 @@
+import VTSequence from "@/components/VTSequence";
+
+# Horizontal Position Relative (HPR)
+
+<VTSequence sequence={["CSI", "Px", "a"]} />
+
+This sequence performs [cursor position (CUP)](/vt/cup) with `x` set
+to the current cursor column plus `x` and `y` set to the current cursor row.
+There is no additional or different behavior for using `HPR`.
+
+The parameter `x` must be an integer greater than or equal to 1. If `x` is less than
+or equal to 0, adjust `x` to be 1. If `x` is omitted, `x` defaults to 1.
+
+Because this invokes `CUP`, the cursor row (`y`) can change if it is
+outside the bounds of the `CUP` operation. For example, if
+[origin mode](#TODO) is set and the current cursor position is outside
+of the scroll region, the row will be adjusted.

website/app/vt/vpa/page.mdx

@@ -0,0 +1,14 @@
+import VTSequence from "@/components/VTSequence";
+
+# Vertical Position Absolute (VPA)
+
+<VTSequence sequence={["CSI", "Py", "d"]} />
+
+This sequence performs [cursor position (CUP)](/vt/cup) with `y` set
+to the parameterized value and `x` set to the current cursor position.
+There is no additional or different behavior for using `VPA`.
+
+Because this invokes `CUP`, the cursor column (`y`) can change if it is
+outside the bounds of the `CUP` operation. For example, if
+[origin mode](#TODO) is set and the current cursor position is outside
+of the scroll region, the column will be adjusted.

website/app/vt/vpr/page.mdx

@@ -0,0 +1,17 @@
+import VTSequence from "@/components/VTSequence";
+
+# Vertical Position Relative (VPR)
+
+<VTSequence sequence={["CSI", "Py", "e"]} />
+
+This sequence performs [cursor position (CUP)](/vt/cup) with `y` set
+to the current cursor row plus `y` and `x` set to the current cursor column.
+There is no additional or different behavior for using `VPR`.
+
+The parameter `y` must be an integer greater than or equal to 1. If `y` is less than
+or equal to 0, adjust `y` to be 1. If `y` is omitted, `y` defaults to 1.
+
+Because this invokes `CUP`, the cursor column (`x`) can change if it is
+outside the bounds of the `CUP` operation. For example, if
+[origin mode](#TODO) is set and the current cursor position is outside
+of the scroll region, the column will be adjusted.

website/components/VTSequence.tsx

@@ -29,7 +29,7 @@ export default function VTSequence({
 }
 
 function VTElem({ elem }: { elem: string }) {
-  const param = elem === "Pn";
+  const param = elem.length > 1 && elem[0] === "P";
   elem = param ? elem[1] : elem;
   const specialChar = special[elem] ?? elem.charCodeAt(0);
   const hex = specialChar.toString(16).padStart(2, "0").toUpperCase();