Rename 'none' kind to 'empty'

pygmt/clib/session.py

@@ -1775,22 +1775,22 @@ def virtualfile_in(  # noqa: PLR0912
             if check_kind == "raster":
                 valid_kinds += ("grid", "image")
             elif check_kind == "vector":
-                valid_kinds += ("none", "matrix", "vectors", "geojson")
+                valid_kinds += ("empty", "matrix", "vectors", "geojson")
             if kind not in valid_kinds:
                 raise GMTInvalidInput(
                     f"Unrecognized data type for {check_kind}: {type(data)}"
                 )
 
         # Decide which virtualfile_from_ function to use
         _virtualfile_from = {
-            "file": contextlib.nullcontext,
             "arg": contextlib.nullcontext,
+            "empty": self.virtualfile_from_vectors,
+            "file": contextlib.nullcontext,
             "geojson": tempfile_from_geojson,
             "grid": self.virtualfile_from_grid,
             "image": tempfile_from_image,
             "stringio": self.virtualfile_from_stringio,
             "matrix": self.virtualfile_from_matrix,
-            "none": self.virtualfile_from_vectors,
             "vectors": self.virtualfile_from_vectors,
         }[kind]
 
@@ -1806,7 +1806,7 @@ def virtualfile_in(  # noqa: PLR0912
                 )
                 warnings.warn(message=msg, category=RuntimeWarning, stacklevel=2)
             _data = (data,) if not isinstance(data, pathlib.PurePath) else (str(data),)
-        elif kind == "none":
+        elif kind == "empty":
             # data is None, so data must be given via x/y/z.
             _data = [x, y]
             if z is not None:

pygmt/helpers/utils.py

@@ -191,18 +191,18 @@ def _check_encoding(
 def data_kind(
     data: Any, required: bool = True
 ) -> Literal[
-    "arg", "file", "geojson", "grid", "image", "matrix", "none", "stringio", "vectors"
+    "arg", "empty", "file", "geojson", "grid", "image", "matrix", "stringio", "vectors"
 ]:
     r"""
     Check the kind of data that is provided to a module.
 
     The argument passed to the ``data`` parameter can have any data type. The
     following data kinds are recognized and returned as ``kind``:
 
-    - ``"none"`: ``data`` is ``None`` and ``required=True``. It means the data is given
-      via a series of vectors like x/y/z
     - ``"arg"``: ``data`` is ``None`` and ``required=False``, or bool, int, float,
       representing an optional argument, used for dealing with optional virtual files
+    - ``"empty"`: ``data`` is ``None`` and ``required=True``. It means the data is given
+      via a series of vectors like x/y/z
     - ``"file"``: a string or a :class:`pathlib.PurePath` object or a sequence of them,
       representing one or more file names
     - ``"geojson"``: a geo-like Python object that implements ``__geo_interface__``
@@ -244,6 +244,11 @@ def data_kind(
     >>> data_kind(data=None, required=False)
     'arg'
 
+    The "empty" kind:
+
+    >>> data_kind(data=None)
+    'empty'
+
     The "file" kind:
 
     >>> [data_kind(data=data) for data in ("file.txt", ("file1.txt", "file2.txt"))]
@@ -295,15 +300,10 @@ def data_kind(
     'vectors'
     >>> data_kind(data=pd.Series([1, 2, 3], name="x"))  # pd.Series
     'vectors'
-
-    The "none" kind:
-
-    >>> data_kind(data=None)
-    'none'
     """
     match data:
         case None if required:  # No data provided and required=True.
-            kind = "none"
+            kind = "empty"
         case str() | pathlib.PurePath():  # One file.
             kind = "file"
         case list() | tuple() if all(

pygmt/src/legend.py

@@ -91,7 +91,7 @@ def legend(
             kwargs["F"] = box
 
     kind = data_kind(spec)
-    if kind not in {"none", "file", "stringio"}:
+    if kind not in {"empty", "file", "stringio"}:
         raise GMTInvalidInput(f"Unrecognized data type: {type(spec)}")
     if kind == "file" and is_nonstr_iter(spec):
         raise GMTInvalidInput("Only one legend specification file is allowed.")

pygmt/src/plot.py

@@ -206,7 +206,7 @@ def plot(self, data=None, x=None, y=None, size=None, direction=None, **kwargs):
 
     kind = data_kind(data)
     extra_arrays = []
-    if kind == "none":  # Add more columns for vectors input
+    if kind == "empty":  # Add more columns for vectors input
         # Parameters for vector styles
         if (
             kwargs.get("S") is not None

pygmt/src/plot3d.py

@@ -184,7 +184,7 @@ def plot3d(
     kind = data_kind(data)
     extra_arrays = []
 
-    if kind == "none":  # Add more columns for vectors input
+    if kind == "empty":  # Add more columns for vectors input
         # Parameters for vector styles
         if (
             kwargs.get("S") is not None

pygmt/src/text.py

@@ -193,7 +193,7 @@ def text_(  # noqa: PLR0912
         raise GMTInvalidInput("'text' can't be None or array when 'position' is given.")
     if textfiles is not None and text is not None:
         raise GMTInvalidInput("'text' can't be specified when 'textfiles' is given.")
-    if kind == "none" and text is None:
+    if kind == "empty" and text is None:
         raise GMTInvalidInput("Must provide text with x/y pairs.")
 
     # Arguments that can accept arrays.
@@ -217,7 +217,7 @@ def text_(  # noqa: PLR0912
 
     extra_arrays = []
     confdict = {}
-    if kind == "none":
+    if kind == "empty":
         for arg, flag, name in array_args:
             if is_nonstr_iter(arg):
                 kwargs["F"] += flag