fixed missing optional dependency of pandas/Styler

src/pyladoc/__init__.py

@@ -33,6 +33,7 @@ else:
         Table = DataFrame | Styler
     except ImportError:
         Table = DataFrame
+        Styler = None
 
     try:
         import matplotlib.pyplot as plt
@@ -475,8 +476,8 @@ class DocumentWriter():
             centered: Whether to center the table in LaTeX output
         """
         assert Table and isinstance(table, Table), 'Table has to be a pandas DataFrame oder DataFrame Styler'
-        styler = table if isinstance(table, Styler) else getattr(table, 'style', None)
-        assert isinstance(styler, Styler), 'Jinja2 package is required for rendering tables'
+        styler = table if Styler and isinstance(table, Styler) else getattr(table, 'style', None)  # type: ignore[truthy-function]
+        assert Styler and isinstance(styler, Styler), 'Jinja2 package is required for rendering pandas tables'  # type: ignore[truthy-function]
 
         def render_to_html() -> str:
             caption_prefix, reference = self._add_item(ref_id, ref_type, prefix_pattern)

src/pyladoc/latex.py

@@ -1,6 +1,5 @@
 from html.parser import HTMLParser
-from typing import Generator, Any, Literal, get_args
-from pandas.io.formats.style import Styler
+from typing import Generator, Any, Literal, get_args, TYPE_CHECKING
 import re
 import os
 import shutil
@@ -8,6 +7,13 @@ import subprocess
 import tempfile
 from .latex_escaping import unicode_to_latex_dict, latex_escape_dict
 
+if TYPE_CHECKING:
+    from pandas.io.formats.style import Styler
+else:
+    try:
+        from pandas.io.formats.style import Styler
+    except ImportError:
+        Styler = None
 
 LatexEngine = Literal['pdflatex', 'lualatex', 'xelatex', 'tectonic']
 
@@ -116,6 +122,9 @@ def render_pandas_styler_table(df_style: Styler, caption: str = '', label: str =
     Returns:
         The LaTeX code.
     """
+    assert Styler, 'Jinja2 package is required for rendering pandas tables'
+    assert isinstance(df_style, Styler), 'df_style has to be of type Styler'
+
     def iter_table(table: dict[str, Any]) -> Generator[str, None, None]:
         yield '\\begin{table}\n'
         if centering: