Function to render the schema with legacy comment-based descriptions

renderSchemaWithLegacyDescriptions.scala

import sangria.ast
import sangria.ast.AstVisitor
import sangria.schema._
import sangria.renderer.{QueryRenderer, QueryRendererConfig, SchemaFilter}
import sangria.visitor.VisitorCommand

def renderSchemaWithLegacyDescriptions(schema: Schema[_, _], filter: SchemaFilter = SchemaFilter.withoutSangriaBuiltIn, config: QueryRendererConfig = QueryRenderer.Pretty) = {
  def commentDescription(node: ast.WithDescription) =
    node.description.toVector.flatMap(sv ⇒ sv.value.split("\\r?\\n").toVector.map(ast.Comment(_)))

  val schemaAst =
    AstVisitor.visit(schema.toAst(filter), AstVisitor {
      case n: ast.DirectiveDefinition if n.description.isDefined ⇒
        VisitorCommand.Transform(n.copy(description = None, comments = n.comments ++ commentDescription(n)))
      case n: ast.InterfaceTypeDefinition if n.description.isDefined ⇒
        VisitorCommand.Transform(n.copy(description = None, comments = n.comments ++ commentDescription(n)))
      case n: ast.EnumTypeDefinition if n.description.isDefined ⇒
        VisitorCommand.Transform(n.copy(description = None, comments = n.comments ++ commentDescription(n)))
      case n: ast.EnumValueDefinition if n.description.isDefined ⇒
        VisitorCommand.Transform(n.copy(description = None, comments = n.comments ++ commentDescription(n)))
      case n: ast.FieldDefinition if n.description.isDefined ⇒
        VisitorCommand.Transform(n.copy(description = None, comments = n.comments ++ commentDescription(n)))
      case n: ast.InputObjectTypeDefinition if n.description.isDefined ⇒
        VisitorCommand.Transform(n.copy(description = None, comments = n.comments ++ commentDescription(n)))
      case n: ast.InputValueDefinition if n.description.isDefined ⇒
        VisitorCommand.Transform(n.copy(description = None, comments = n.comments ++ commentDescription(n)))
      case n: ast.ObjectTypeDefinition if n.description.isDefined ⇒
        VisitorCommand.Transform(n.copy(description = None, comments = n.comments ++ commentDescription(n)))
      case n: ast.ScalarTypeDefinition if n.description.isDefined ⇒
        VisitorCommand.Transform(n.copy(description = None, comments = n.comments ++ commentDescription(n)))
      case n: ast.UnionTypeDefinition if n.description.isDefined ⇒
        VisitorCommand.Transform(n.copy(description = None, comments = n.comments ++ commentDescription(n)))
    })

  QueryRenderer.render(schemaAst, config)
}