_yaml: Introduce 'get_sequence()' and 'sequence_at()'/'mapping_at()'

- Adding 'get_sequence' on MappingNode to access sequences in a mapping
- Adding 'sequence_at' on SequenceNode to access sequences in a sequence
- Adding 'mapping_at' on SequenceNode to access mappings in a sequence

Using "*_at" in sequences allows us to quickly understand if we are
dealing with a sequence or a mapping.

3 files changed, 5 insertions, 5 deletions

diff --git a/src/buildstream/_options/optionenum.py b/src/buildstream/_options/optionenum.py
index 04a19395b..f04cecd8b 100644
--- a/src/buildstream/_options/optionenum.py
+++ b/src/buildstream/_options/optionenum.py
@@ -46,7 +46,7 @@ class OptionEnum(Option):
 
         _yaml.node_validate(node, valid_symbols)
 
-        self.values = _yaml.node_get(node, list, 'values', default_value=[])
+        self.values = node.get_sequence('values', default=[]).as_str_list()
         if not self.values:
             raise LoadError(LoadErrorReason.INVALID_DATA,
                             "{}: No values specified for {} option '{}'"
diff --git a/src/buildstream/_options/optionflags.py b/src/buildstream/_options/optionflags.py
index eba3a8dd5..c9758e403 100644
--- a/src/buildstream/_options/optionflags.py
+++ b/src/buildstream/_options/optionflags.py
@@ -53,11 +53,11 @@ class OptionFlags(Option):
                             "{}: No values specified for {} option '{}'"
                             .format(_yaml.node_get_provenance(node), self.OPTION_TYPE, self.name))
 
-        self.value = _yaml.node_get(node, list, 'default', default_value=[])
+        self.value = node.get_sequence('default', default=[]).as_str_list()
         self.validate(self.value, _yaml.node_get_provenance(node, 'default'))
 
     def load_value(self, node, *, transform=None):
-        self.value = _yaml.node_get(node, list, self.name)
+        self.value = node.get_sequence(self.name).as_str_list()
         if transform:
             self.value = [transform(x) for x in self.value]
         self.value = sorted(self.value)
@@ -90,4 +90,4 @@ class OptionFlags(Option):
     def load_valid_values(self, node):
         # Allow the more descriptive error to raise when no values
         # exist rather than bailing out here (by specifying default_value)
-        return _yaml.node_get(node, list, 'values', default_value=[])
+        return node.get_sequence('values', default=[]).as_str_list()
diff --git a/src/buildstream/_options/optionpool.py b/src/buildstream/_options/optionpool.py
index 25b96fa98..9a4a88c36 100644
--- a/src/buildstream/_options/optionpool.py
+++ b/src/buildstream/_options/optionpool.py
@@ -248,7 +248,7 @@ class OptionPool():
     # Return true if a conditional was processed.
     #
     def _process_one_node(self, node):
-        conditions = _yaml.node_get(node, list, '(?)', default_value=None)
+        conditions = node.get_sequence('(?)', default=None)
         assertion = node.get_str('(!)', default=None)
 
         # Process assersions first, we want to abort on the first encountered