Added escape_name function to escape individual SQL names and `esca…

…pe_full_name` function to escape dot-separated full names (#316)

Ported from https://github.com/databrickslabs/ucx by @larsgeorge-db ,
@JCZuurmond , and @asnare .

src/databricks/labs/lsql/escapes.py

@@ -0,0 +1,19 @@
+def escape_name(name: str) -> str:
+    """Escapes the name to make it SQL safe."""
+    return f"`{name.strip('`').replace('`', '``')}`"
+
+
+def escape_full_name(full_name: str) -> str:
+    """
+    Escapes the full name components to make them SQL safe.
+
+    Args:
+        full_name (str): The dot-separated name of a catalog object.
+
+    Returns:
+         str: The path with all parts escaped in backticks.
+    """
+    if not full_name:
+        return full_name
+    parts = full_name.split(".", maxsplit=2)
+    return ".".join(escape_name(part) for part in parts)

tests/unit/test_escapes.py

@@ -0,0 +1,34 @@
+import pytest
+
+from databricks.labs.lsql.escapes import escape_full_name, escape_name
+
+
+@pytest.mark.parametrize(
+    "path,expected",
+    [
+        ("a", "`a`"),
+        ("a.b", "`a`.`b`"),
+        ("a.b.c", "`a`.`b`.`c`"),
+        ("`a`.b.c", "`a`.`b`.`c`"),
+        ("a.`b`.c", "`a`.`b`.`c`"),
+        ("a.b.`c`", "`a`.`b`.`c`"),
+        ("`a.b`.c", "`a`.`b`.`c`"),
+        ("a.`b.c`", "`a`.`b`.`c`"),
+        ("`a.b`.`c`", "`a`.`b`.`c`"),
+        ("`a`.`b.c`", "`a`.`b`.`c`"),
+        ("`a`.`b`.`c`", "`a`.`b`.`c`"),
+        ("a.b.c.d", "`a`.`b`.`c.d`"),
+        ("a-b.c.d", "`a-b`.`c`.`d`"),
+        ("a.b-c.d", "`a`.`b-c`.`d`"),
+        ("a.b.c-d", "`a`.`b`.`c-d`"),
+        ("a.b.c`d", "`a`.`b`.`c``d`"),
+        ("✨.🍰.✨", "`✨`.`🍰`.`✨`"),
+        ("", ""),
+    ],
+)
+def test_escaped_path(path: str, expected: str) -> None:
+    assert escape_full_name(path) == expected
+
+
+def test_escaped_when_column_contains_period() -> None:
+    assert escape_name("column.with.periods") == "`column.with.periods`"