package parser import "github.com/hashicorp/hcl/hcl/ast" // flattenObjects takes an AST node, walks it, and flattens func flattenObjects(node ast.Node) { ast.Walk(node, func(n ast.Node) (ast.Node, bool) { // We only care about lists, because this is what we modify list, ok := n.(*ast.ObjectList) if !ok { return n, true } // Rebuild the item list items := make([]*ast.ObjectItem, 0, len(list.Items)) frontier := make([]*ast.ObjectItem, len(list.Items)) copy(frontier, list.Items) for len(frontier) > 0 { // Pop the current item n := len(frontier) item := frontier[n-1] frontier = frontier[:n-1] switch v := item.Val.(type) { case *ast.ObjectType: items, frontier = flattenObjectType(v, item, items, frontier) case *ast.ListType: items, frontier = flattenListType(v, item, items, frontier) default: items = append(items, item) } } // Reverse the list since the frontier model runs things backwards for i := len(items)/2 - 1; i >= 0; i-- { opp := len(items) - 1 - i items[i], items[opp] = items[opp], items[i] } // Done! Set the original items list.Items = items return n, true }) } func flattenListType( ot *ast.ListType, item *ast.ObjectItem, items []*ast.ObjectItem, frontier []*ast.ObjectItem) ([]*ast.ObjectItem, []*ast.ObjectItem) { // If the list is empty, keep the original list if len(ot.List) == 0 { items = append(items, item) return items, frontier } // All the elements of this object must also be objects! for _, subitem := range ot.List { if _, ok := subitem.(*ast.ObjectType); !ok { items = append(items, item) return items, frontier } } // Great! We have a match go through all the items and flatten for _, elem := range ot.List { // Add it to the frontier so that we can recurse frontier = append(frontier, &ast.ObjectItem{ Keys: item.Keys, Assign: item.Assign, Val: elem, LeadComment: item.LeadComment, LineComment: item.LineComment, }) } return items, frontier } func flattenObjectType( ot *ast.ObjectType, item *ast.ObjectItem, items []*ast.ObjectItem, frontier []*ast.ObjectItem) ([]*ast.ObjectItem, []*ast.ObjectItem) { // If the list has no items we do not have to flatten anything if ot.List.Items == nil { items = append(items, item) return items, frontier } // All the elements of this object must also be objects! for _, subitem := range ot.List.Items { if _, ok := subitem.Val.(*ast.ObjectType); !ok { items = append(items, item) return items, frontier } } // Great! We have a match go through all the items and flatten for _, subitem := range ot.List.Items { // Copy the new key keys := make([]*ast.ObjectKey, len(item.Keys)+len(subitem.Keys)) copy(keys, item.Keys) copy(keys[len(item.Keys):], subitem.Keys) // Add it to the frontier so that we can recurse frontier = append(frontier, &ast.ObjectItem{ Keys: keys, Assign: item.Assign, Val: subitem.Val, LeadComment: item.LeadComment, LineComment: item.LineComment, }) } return items, frontier }