Merge pull request #1253 from python-cmd2/1252-str-to-bool

Enhance str_to_bool() to accept other types

Author: kotfu

cmd2/utils.py

@@ -89,19 +89,26 @@ def strip_quotes(arg: str) -> str:
     return arg
 
 
-def str_to_bool(val: str) -> bool:
-    """Converts a string to a boolean based on its value.
+def to_bool(val: Any) -> bool:
+    """Converts anything to a boolean based on its value.
 
-    :param val: string being converted
-    :return: boolean value expressed in the string
+    Strings like "True", "true", "False", and "false" return True, True, False, and False
+    respectively. All other values are converted using bool()
+
+    :param val: value being converted
+    :return: boolean value expressed in the passed in value
     :raises: ValueError if the string does not contain a value corresponding to a boolean value
     """
     if isinstance(val, str):
         if val.capitalize() == str(True):
             return True
         elif val.capitalize() == str(False):
             return False
-    raise ValueError("must be True or False (case-insensitive)")
+        raise ValueError("must be True or False (case-insensitive)")
+    elif isinstance(val, bool):
+        return val
+    else:
+        return bool(val)
 
 
 class Settable:
@@ -126,7 +133,7 @@ def __init__(
         :param name: name of the instance attribute being made settable
         :param val_type: callable used to cast the string value from the command line into its proper type and
                          even validate its value. Setting this to bool provides tab completion for true/false and
-                         validation using str_to_bool(). The val_type function should raise an exception if it fails.
+                         validation using to_bool(). The val_type function should raise an exception if it fails.
                          This exception will be caught and printed by Cmd.do_set().
         :param description: string describing this setting
         :param settable_object: object to which the instance attribute belongs (e.g. self)
@@ -153,7 +160,7 @@ def get_bool_choices(_) -> List[str]:  # type: ignore[no-untyped-def]
                 """Used to tab complete lowercase boolean values"""
                 return ['true', 'false']
 
-            val_type = str_to_bool
+            val_type = to_bool
             choices_provider = cast(ChoicesProviderFunc, get_bool_choices)
 
         self.name = name

docs/api/utils.rst

@@ -88,7 +88,7 @@ Text Alignment
 Miscellaneous
 -------------
 
-.. autofunction:: cmd2.utils.str_to_bool
+.. autofunction:: cmd2.utils.to_bool
 
 .. autofunction:: cmd2.utils.categorize
 

tests/test_utils.py

@@ -824,28 +824,41 @@ def test_align_right_wide_fill_needs_padding():
     assert aligned == fill_char + ' ' + text
 
 
-def test_str_to_bool_true():
-    assert cu.str_to_bool('true')
-    assert cu.str_to_bool('True')
-    assert cu.str_to_bool('TRUE')
-    assert cu.str_to_bool('tRuE')
+def test_to_bool_str_true():
+    assert cu.to_bool('true')
+    assert cu.to_bool('True')
+    assert cu.to_bool('TRUE')
+    assert cu.to_bool('tRuE')
 
 
-def test_str_to_bool_false():
-    assert not cu.str_to_bool('false')
-    assert not cu.str_to_bool('False')
-    assert not cu.str_to_bool('FALSE')
-    assert not cu.str_to_bool('fAlSe')
+def test_to_bool_str_false():
+    assert not cu.to_bool('false')
+    assert not cu.to_bool('False')
+    assert not cu.to_bool('FALSE')
+    assert not cu.to_bool('fAlSe')
 
 
-def test_str_to_bool_invalid():
+def test_to_bool_str_invalid():
     with pytest.raises(ValueError):
-        cu.str_to_bool('other')
+        cu.to_bool('other')
 
 
-def test_str_to_bool_bad_input():
-    with pytest.raises(ValueError):
-        cu.str_to_bool(1)
+def test_to_bool_bool():
+    assert cu.to_bool(True)
+    assert not cu.to_bool(False)
+
+
+def test_to_bool_int():
+    assert cu.to_bool(1)
+    assert cu.to_bool(-1)
+    assert not cu.to_bool(0)
+
+
+def test_to_bool_float():
+    assert cu.to_bool(2.35)
+    assert cu.to_bool(0.25)
+    assert cu.to_bool(-3.1415)
+    assert not cu.to_bool(0)
 
 
 def test_find_editor_specified():