[SyntaxBuilder] Add default conformance to syntax collection elements

Author: kimdv

utils/gyb_syntax_support/__init__.py

@@ -15,6 +15,7 @@
 from .StmtNodes import STMT_NODES  # noqa: I201
 from .Trivia import TRIVIAS  # noqa: I201
 from .TypeNodes import TYPE_NODES  # noqa: I201
+from .kinds import syntax_buildable_child_type
 
 
 # Re-export global constants
@@ -179,3 +180,42 @@ def _digest_trivia(trivia):
         _digest_trivia(trivia)
 
     return digest.hexdigest()
+
+
+def syntax_collection_element_to_collection_mapping():
+    """
+    Generates a lookup table to find syntax collection type by syntax collection
+    element type.
+
+    Example:
+    {
+        'SyntaxBuildable': [
+            'StringLiteralSegments', 
+            'PrecedenceGroupAttributeList', 
+            'AttributeList', 
+            'SpecializeAttributeSpecList', 
+            'SwitchCaseList'
+        ],
+        'IfConfigClause': [
+            'IfConfigClauseList'
+        ],
+    }
+    """
+    collection_map = {}
+
+    for node in SYNTAX_NODES:
+        if node.is_syntax_collection():
+            syntax_collection_syntax_kind = node.syntax_kind
+
+            syntax_child_type = syntax_buildable_child_type(
+                node.collection_element_type, 
+                node.collection_element, 
+                node.is_token())
+
+            if syntax_child_type not in collection_map:
+                collection_map[syntax_child_type] = []
+
+            collection_map[syntax_child_type] \
+                .append(syntax_collection_syntax_kind)
+
+    return collection_map

utils/gyb_syntax_support/protocolsMap.py

@@ -1,18 +1,15 @@
 SYNTAX_BUILDABLE_EXPRESSIBLE_AS_CONFORMANCES = {
-    'ExpressibleAsConditionElement': [
-        'ExpressibleAsConditionElementList'
+    'DeclBuildable': [
+        'CodeBlockItem',
+        'MemberDeclListItem',
+        'SyntaxBuildable'
     ],
-    'ExpressibleAsDeclBuildable': [
-        'ExpressibleAsCodeBlockItem',
-        'ExpressibleAsMemberDeclListItem',
-        'ExpressibleAsSyntaxBuildable'
+    'StmtBuildable': [
+        'CodeBlockItem',
+        'SyntaxBuildable'
     ],
-    'ExpressibleAsStmtBuildable': [
-        'ExpressibleAsCodeBlockItem',
-        'ExpressibleAsSyntaxBuildable'
-    ],
-    'ExpressibleAsExprList': [
-        'ExpressibleAsConditionElement',
-        'ExpressibleAsSyntaxBuildable'
+    'ExprList': [
+        'ConditionElement',
+        'SyntaxBuildable'
     ]
 }