interpreter: Add values() method for dict

docs/markdown/snippets/add_dict_values.md

@@ -0,0 +1,12 @@
+## Added a `values()` method for dictionaries
+
+Mesons built-in [[@dict]] type now supports the [[dict.values]] method
+to retrieve the dictionary values as an array, analogous to the
+[[dict.keys]] method.
+
+```meson
+dict = { 'b': 'world', 'a': 'hello' }
+
+[[#dict.keys]] # Returns ['a', 'b']
+[[#dict.values]] # Returns ['hello', 'world']
+```

docs/yaml/elementary/dict.yml

@@ -45,4 +45,11 @@ methods:
 
 - name: keys
   returns: array[str]
-  description: Returns an array of keys in the dictionary.
+  description: Returns an array of keys in the dictionary, sorted in ascending order.
+
+- name: values
+  returns: array[any]
+  since: 1.10.0
+  description: |
+    Returns an array of values in the dictionary, sorted by the
+    corresponding keys in ascending order.

mesonbuild/interpreter/primitives/dict.py

@@ -9,6 +9,7 @@
     IterableObject,
     MesonOperator,
     ObjectHolder,
+    FeatureNew,
     typed_operator,
     noKwargs,
     noPosargs,
@@ -48,6 +49,9 @@ def iter_self(self) -> T.Iterator[T.Tuple[str, TYPE_var]]:
     def size(self) -> int:
         return len(self.held_object)
 
+    def _keys_getter(self) -> T.List[str]:
+        return sorted(self.held_object)
+
     @noKwargs
     @typed_pos_args('dict.has_key', str)
     @InterpreterObject.method('has_key')
@@ -58,7 +62,14 @@ def has_key_method(self, args: T.Tuple[str], kwargs: TYPE_kwargs) -> bool:
     @noPosargs
     @InterpreterObject.method('keys')
     def keys_method(self, args: T.List[TYPE_var], kwargs: TYPE_kwargs) -> T.List[str]:
-        return sorted(self.held_object)
+        return self._keys_getter()
+
+    @noKwargs
+    @noPosargs
+    @InterpreterObject.method('values')
+    @FeatureNew('dict.values', '1.10.0')
+    def values_method(self, args: T.List[TYPE_var], kwargs: TYPE_kwargs) -> T.List[TYPE_var]:
+        return [self.held_object[k] for k in self._keys_getter()]
 
     @noArgsFlattening
     @noKwargs

test cases/common/188 dict/meson.build

@@ -16,12 +16,24 @@ endforeach
 
 assert(i == 3, 'There should be three elements in that dictionary')
 
+# Test keys() works as expected (note that it sorts the keys)
+assert(dict.keys() == ['baz', 'foo', 'foo bar'], 'Keys returned unexpected list')
+
+# Test values() works as expected (note that it sorts first, to match keys())
+assert(dict.values() == ['foo', 'bar', 'baz'])
+
 empty_dict = {}
 
 foreach key, value : empty_dict
   assert(false, 'This dict should be empty')
 endforeach
 
+# Test keys() returns an empty list
+assert(empty_dict.keys() == [], 'Keys for an empty dict should be an empty list')
+
+# Test values() returns an empty list
+assert(empty_dict.values() == [], 'Values for an empty dict should be an empty list')
+
 d1 = empty_dict + {'a' : 'b'}
 assert(d1 == {'a' : 'b'}, 'dict addition is not working')