constants(SplitWindowDirection): Add enum and map for split pane directions

Author: tony

src/libtmux/constants.py

@@ -32,3 +32,21 @@ class NewWindowDirection(enum.Enum):
     NewWindowDirection.Before: "-b",
     NewWindowDirection.After: "-a",
 }
+
+
+class SplitWindowDirection(enum.Enum):
+    """Used for *adjustment* in :meth:`Pane.split()`."""
+
+    Above = "ABOVE"
+    Below = "BELOW"  # default with no args
+    Right = "RIGHT"
+    Left = "LEFT"
+
+
+SPLIT_WINDOW_DIRECTION_FLAG_MAP: t.Dict[SplitWindowDirection, t.List[str]] = {
+    # -v is assumed, but for explicitness it is passed
+    SplitWindowDirection.Above: ["-v", "-b"],
+    SplitWindowDirection.Below: ["-v"],
+    SplitWindowDirection.Right: ["-h"],
+    SplitWindowDirection.Left: ["-h", "-b"],
+}