Allow callable references in sqlite-utils convert, closes #686

This allows users to pass just a callable reference like `r.parsedate`
instead of `r.parsedate(value)` to the convert command. The code now
detects when the input evaluates to a callable and uses it directly.

Examples that now work:
- sqlite-utils convert my.db table col r.parsedate
- sqlite-utils convert my.db table col json.loads --import json

Author: claude

docs/cli.rst

@@ -1849,7 +1849,19 @@ These recipes can be used in the code passed to ``sqlite-utils convert`` like th
     sqlite-utils convert my.db mytable mycolumn \
       'r.jsonsplit(value)'
 
-To use any of the documented parameters, do this:
+You can also pass the recipe function directly without the ``(value)`` part - sqlite-utils will detect that it is a callable and use it automatically:
+
+.. code-block:: bash
+
+    sqlite-utils convert my.db mytable mycolumn r.parsedate
+
+This shorter syntax works for any callable, including functions from imported modules:
+
+.. code-block:: bash
+
+    sqlite-utils convert my.db mytable mycolumn json.loads --import json
+
+To use any of the documented parameters, use the full function call syntax:
 
 .. code-block:: bash
 

sqlite_utils/utils.py

@@ -450,13 +450,26 @@ def progressbar(*args, **kwargs):
 
 def _compile_code(code, imports, variable="value"):
     globals = {"r": recipes, "recipes": recipes}
+    # Handle imports first so they're available for all approaches
+    for import_ in imports:
+        globals[import_.split(".")[0]] = __import__(import_)
+
     # If user defined a convert() function, return that
     try:
         exec(code, globals)
         return globals["convert"]
     except (AttributeError, SyntaxError, NameError, KeyError, TypeError):
         pass
 
+    # Check if code is a direct callable reference
+    # e.g. "r.parsedate" instead of "r.parsedate(value)"
+    try:
+        fn = eval(code, globals)
+        if callable(fn):
+            return fn
+    except Exception:
+        pass
+
     # Try compiling their code as a function instead
     body_variants = [code]
     # If single line and no 'return', try adding the return
@@ -478,8 +491,6 @@ def _compile_code(code, imports, variable="value"):
     if code_o is None:
         raise SyntaxError("Could not compile code")
 
-    for import_ in imports:
-        globals[import_.split(".")[0]] = __import__(import_)
     exec(code_o, globals)
     return globals["fn"]
 

tests/test_cli_convert.py

@@ -645,3 +645,51 @@ def test_convert_handles_falsey_values(fresh_db_and_path):
     assert result.exit_code == 0, result.output
     assert db["t"].get(1)["x"] == 1
     assert db["t"].get(2)["x"] == 2
+
+
+@pytest.mark.parametrize(
+    "code",
+    [
+        # Direct callable reference (issue #686)
+        "r.parsedate",
+        "recipes.parsedate",
+        # Traditional call syntax still works
+        "r.parsedate(value)",
+        "recipes.parsedate(value)",
+    ],
+)
+def test_convert_callable_reference(test_db_and_path, code):
+    """Test that callable references like r.parsedate work without (value)"""
+    db, db_path = test_db_and_path
+    result = CliRunner().invoke(
+        cli.cli, ["convert", db_path, "example", "dt", code], catch_exceptions=False
+    )
+    assert result.exit_code == 0, result.output
+    rows = list(db["example"].rows)
+    assert rows[0]["dt"] == "2019-10-05"
+    assert rows[1]["dt"] == "2019-10-06"
+    assert rows[2]["dt"] == ""
+    assert rows[3]["dt"] is None
+
+
+def test_convert_callable_reference_with_import(fresh_db_and_path):
+    """Test callable reference from an imported module"""
+    db, db_path = fresh_db_and_path
+    db["example"].insert({"id": 1, "data": '{"name": "test"}'})
+    result = CliRunner().invoke(
+        cli.cli,
+        [
+            "convert",
+            db_path,
+            "example",
+            "data",
+            "json.loads",
+            "--import",
+            "json",
+        ],
+        catch_exceptions=False,
+    )
+    assert result.exit_code == 0, result.output
+    # json.loads returns a dict, which sqlite stores as JSON string
+    row = db["example"].get(1)
+    assert row["data"] == '{"name": "test"}'