Substantial refactor more along the lines I’d like to ship (#1)

* WIP: Refactor node handling

* WIP: clean up the HTML parsing stuff.

* Move clsx -> separate classnames.py

* Clean up format_interpolation() and convert()

* Take a hard dependency on MarkupSafe

* Getting closer with clean impl.

* This is starting to feel coherent.

Author: davepeck

html_tstring/__init__.py

@@ -0,0 +1,17 @@
+from markupsafe import Markup, escape
+
+from .nodes import Comment, DocumentType, Element, Fragment, Text
+from .processor import html
+
+# We consider `Markup` and `escape` to be part of this module's public API
+
+__all__ = [
+    "Comment",
+    "DocumentType",
+    "Element",
+    "escape",
+    "Fragment",
+    "html",
+    "Markup",
+    "Text",
+]

html_tstring/classnames.py

@@ -0,0 +1,46 @@
+def classnames(*args: object) -> str:
+    """
+    Construct a space-separated class string from various inputs.
+
+    Accepts strings, lists/tuples of strings, and dicts mapping class names to
+    boolean values. Ignores None and False values.
+
+    Examples:
+        classnames("btn", "btn-primary") -> "btn btn-primary"
+        classnames("btn", {"btn-primary": True, "disabled": False}) -> "btn btn-primary"
+        classnames(["btn", "btn-primary"], {"disabled": True}) -> "btn btn-primary disabled"
+        classnames("btn", None, False, "active") -> "btn active"
+
+    Args:
+        *args: Variable length argument list containing strings, lists/tuples,
+               or dicts.
+
+    Returns:
+        A single string with class names separated by spaces.
+    """
+    classes: list[str] = []
+    # Use a queue to process arguments iteratively, preserving order.
+    queue = list(args)
+
+    while queue:
+        arg = queue.pop(0)
+
+        if not arg:  # Handles None, False, empty strings/lists/dicts
+            continue
+
+        if isinstance(arg, str):
+            classes.append(arg)
+        elif isinstance(arg, dict):
+            for key, value in arg.items():
+                if value:
+                    classes.append(key)
+        elif isinstance(arg, (list, tuple)):
+            # Add items to the front of the queue to process them next, in order.
+            queue[0:0] = arg
+        elif isinstance(arg, bool):
+            pass  # Explicitly ignore booleans not in a dict
+        else:
+            raise ValueError(f"Invalid class argument type: {type(arg).__name__}")
+
+    # Filter out empty strings and join the result.
+    return " ".join(stripped for c in classes if (stripped := c.strip()))

html_tstring/classnames_test.py

@@ -0,0 +1,74 @@
+import pytest
+
+from .classnames import classnames
+
+
+def test_classnames_empty():
+    assert classnames() == ""
+
+
+def test_classnames_strings():
+    assert classnames("btn", "btn-primary") == "btn btn-primary"
+
+
+def test_classnames_strings_strip():
+    assert classnames("  btn  ", " btn-primary ") == "btn btn-primary"
+
+
+def test_cslx_empty_strings():
+    assert classnames("", "btn", "", "btn-primary", "") == "btn btn-primary"
+
+
+def test_classnames_lists_and_tuples():
+    assert (
+        classnames(["btn", "btn-primary"], ("active", "disabled"))
+        == "btn btn-primary active disabled"
+    )
+
+
+def test_classnames_dicts():
+    assert (
+        classnames(
+            "btn",
+            {"btn-primary": True, "disabled": False, "active": True, "shown": "yes"},
+        )
+        == "btn btn-primary active shown"
+    )
+
+
+def test_classnames_mixed_inputs():
+    assert (
+        classnames(
+            "btn",
+            ["btn-primary", "active"],
+            {"disabled": True, "hidden": False},
+            ("extra",),
+        )
+        == "btn btn-primary active disabled extra"
+    )
+
+
+def test_classnames_ignores_none_and_false():
+    assert (
+        classnames("btn", None, False, "active", {"hidden": None, "visible": True})
+        == "btn active visible"
+    )
+
+
+def test_classnames_raises_type_error_on_invalid_input():
+    with pytest.raises(ValueError):
+        classnames(123)
+
+    with pytest.raises(ValueError):
+        classnames(["btn", 456])
+
+
+def test_classnames_kitchen_sink():
+    assert (
+        classnames(
+            "foo",
+            [1 and "bar", {"baz": False, "bat": None}, ["hello", ["world"]]],
+            "cya",
+        )
+        == "foo bar hello world cya"
+    )