Make CommentGroups AST-children of Files

Previously they were roots, with children hanging off them. Now they are children of Files, and both CommentGroups and Comments can be discovered using AstNode.getAChild.

The PrintAst pass is also adapted to account for their new position.

Author: smowton

extractor/dbscheme/tables.go

@@ -706,7 +706,9 @@ var HasLocationTable = NewTable("has_location",
 // CommentGroupsTable is the table defining comment group entities
 var CommentGroupsTable = NewTable("comment_groups",
 	EntityColumn(CommentGroupType, "id").Key(),
-)
+	EntityColumn(FileType, "parent"),
+	IntColumn("idx"),
+).KeySet("parent", "idx")
 
 // CommentsTable is the table defining comment entities
 var CommentsTable = NewTable("comments",

extractor/extractor.go

@@ -532,8 +532,8 @@ func extractFileNode(tw *trap.Writer, nd *ast.File) {
 		extractDecl(tw, decl, lbl, i)
 	}
 
-	for _, cg := range nd.Comments {
-		extractCommentGroup(tw, cg)
+	for i, cg := range nd.Comments {
+		extractCommentGroup(tw, cg, lbl, i)
 	}
 
 	extractDoc(tw, nd.Doc, lbl)
@@ -548,9 +548,9 @@ func extractDoc(tw *trap.Writer, doc *ast.CommentGroup, elt trap.Label) {
 }
 
 // extractCommentGroup extracts information about a doc comment group
-func extractCommentGroup(tw *trap.Writer, cg *ast.CommentGroup) {
+func extractCommentGroup(tw *trap.Writer, cg *ast.CommentGroup, parent trap.Label, idx int) {
 	lbl := tw.Labeler.LocalID(cg)
-	dbscheme.CommentGroupsTable.Emit(tw, lbl)
+	dbscheme.CommentGroupsTable.Emit(tw, lbl, parent, idx)
 	extractNodeLocation(tw, cg, lbl)
 	for i, c := range cg.List {
 		extractComment(tw, c, lbl, i)

extractor/gomodextractor.go

@@ -144,7 +144,7 @@ func extractGoModComments(tw *trap.Writer, expr modfile.Expr, exprlbl trap.Label
 
 	// extract a pseudo `@commentgroup` for each expr that contains their associated comments
 	grouplbl := tw.Labeler.LocalID(GoModExprCommentWrapper{expr})
-	dbscheme.CommentGroupsTable.Emit(tw, grouplbl)
+	dbscheme.CommentGroupsTable.Emit(tw, grouplbl, tw.Labeler.FileLabel(), 0)
 	dbscheme.DocCommentsTable.Emit(tw, exprlbl, grouplbl)
 
 	var allComments []modfile.Comment

ql/src/go.dbscheme

@@ -49,7 +49,8 @@ containerparent(int parent: @container ref, unique int child: @container ref);
 
 has_location(unique int locatable: @locatable ref, int location: @location ref);
 
-comment_groups(unique int id: @comment_group);
+#keyset[parent, idx]
+comment_groups(unique int id: @comment_group, int parent: @file ref, int idx: int ref);
 
 comments(unique int id: @comment, int kind: int ref, int parent: @comment_group ref, int idx: int ref, string text: string ref);