reorder things and add targets

Author: finn-rudolph

docs/source/reference/api.rst

@@ -7,7 +7,7 @@ API
 
     verbs
     operators/index
-    functions
+    targets
 
 Table
 -----

docs/source/reference/functions.rst

@@ -1,6 +1,6 @@
-================
-Column Operators
-================
+=================
+Column Operations
+=================
 
 .. toctree::
    :maxdepth: 1
@@ -17,8 +17,25 @@ Column Operators
    sorting_markers
    horizontal_aggregation
 
+
 .. currentmodule:: pydiverse.transform
 
 .. autoclass:: ColExpr
-   :noindex:
+   :no-index:
    :members: dtype
+
+.. autosummary::
+    :toctree: _generated/
+    :template: autosummary/short_title.rst
+    :nosignatures:
+
+    lit
+    when
+
+.. autosummary::
+    :toctree: _generated/
+    :template: autosummary/short_title.rst
+    :nosignatures:
+
+    ColExpr.cast
+    ColExpr.map

docs/source/reference/operators/index.rst

@@ -0,0 +1,14 @@
+=========================
+Backends / Export Targets
+=========================
+
+.. currentmodule:: pydiverse.transform
+.. autosummary::
+    :toctree: _generated/
+    :nosignatures:
+    :template: autosummary/short_title.rst
+
+    DuckDb
+    Pandas
+    Polars
+    SqlAlchemy

docs/source/reference/targets.rst

@@ -142,6 +142,22 @@ def export(
     *,
     schema_overrides: dict[Col, Any] | None = None,
 ) -> Pipeable:
+    """Convert a pydiverse.transform Table to a data frame.
+
+    Parameters
+    ----------
+    The pydiverse.transform Table or column expression to be exported.
+
+    target
+        Can currently be either a `Polars` or `Pandas` object. For polars, one can
+        specify whether a DataFrame or LazyFrame is returned via the `lazy` kwarg.
+        If `lazy=True`, no actual computations are performed, they just get stored in
+        the LazyFrame.
+
+    Returns
+    -------
+    A polars or pandas DataFrame / LazyFrame or a series.
+    """
     if isinstance(data, ColExpr):
         # Find the common ancestor of all AST nodes of columns appearing in the
         # expression.