#38 - fixed field selection syntax:

- compose field selection with current arrow;
Grupo-Abraxas · Jul 11, 2018 · ef35209 · ef35209
1 parent 4bc97c1
commit ef35209
Show file tree

Hide file tree

Showing 3 changed files with 39 additions and 6 deletions.
diff --git a/src/main/scala/com/abraxas/slothql/mapper/ScalaExpr.scala b/src/main/scala/com/abraxas/slothql/mapper/ScalaExpr.scala
@@ -84,7 +84,12 @@ object ScalaExpr {
  protected trait FieldSelectionOps extends Dynamic {
  expr: ScalaExpr =>
 
- def selectDynamic(k: String)(implicit ev: Syntax.HasField[Source, Symbol @@ k.type]): SelectField[Source, k.type, ev.Value] = SelectField(k)
+ def selectDynamic[V, A <: Arrow](k: String)(
+ implicit
+ ev0: Syntax.HasField.Aux[Target, Symbol @@ k.type, V],
+ ev1: expr.type <:< A, // using `expr.type` directly in `compose` would require _existential types_
+ compose: Arrow.Compose[SelectField[Target, k.type, V], A]
+ ): compose.Out = compose(SelectField(k), expr)
  }
 
  object Syntax {

diff --git a/src/test/scala/com/abraxas/slothql/TestArrows.scala b/src/test/scala/com/abraxas/slothql/TestArrows.scala
@@ -99,6 +99,12 @@ object FunctorsTest {
  // ]{type Source = Book;type Target = Option[String]}
  // = MBind(SelectField(pseudonym)) ∘ SelectField(author)
 
+ val selIsbn = ScalaExpr[Book].meta.isbn
+ // Arrow.Composition[
+ // ScalaExpr.SelectField[Meta, isbn, String],
+ // ScalaExpr.SelectField[Book, meta, Meta]
+ // ]{type Source = Book;type Target = String}
+ // = SelectField(isbn) ∘ SelectField(meta)
 
 // val mapped0 = Functor.map(sel2 ∘ sel1).to[GraphPath]
 // val mapped1 = Functor.map(sel3 ∘ (sel2 ∘ sel1)).to[GraphPath]

diff --git a/src/test/scala/com/abraxas/slothql/test/models/Book.scala b/src/test/scala/com/abraxas/slothql/test/models/Book.scala
@@ -5,9 +5,10 @@ import shapeless.syntax.singleton._
 
 import com.abraxas.slothql.mapper.{ GraphRepr, Schema }
 
-case class Book(author: Option[Author], pages: List[Page])
+case class Book(author: Option[Author], pages: List[Page], meta: Meta)
 case class Author(name: String, pseudonym: Option[String])
 case class Page(text: String)
+case class Meta(isbn: String)
 
 object Book {
  object PageListRepr extends GraphRepr.Relation {
@@ -31,16 +32,23 @@ object Book {
  type Labels = Witness.`"Book"`.T :: HNil
  type Fields = HNil
  type Outgoing = Witness.`'author`.Field[GraphRepr.Node.Optional[Author.AuthorRepr.type]] ::
- Witness.`'pages` .Field[PageListRepr.type] :: HNil
+ Witness.`'pages` .Field[PageListRepr.type] ::
+ Witness.`'meta` .Field[Meta.MetaRepr.type] :: HNil
 
  lazy val Labels: Labels = "Book".narrow :: HNil
  lazy val Fields: Fields = HNil
  lazy val Outgoing: Outgoing = 'author ->> GraphRepr.Node.Optional(Author.AuthorRepr) ::
- 'pages ->> PageListRepr :: HNil
+ 'pages ->> PageListRepr ::
+ 'meta ->> Meta.MetaRepr :: HNil
 
  lazy val labels: List[String] = List("Book")
- lazy val fields: Map[String, GraphRepr.Property] = Map("author" -> GraphRepr.Property[String])
- lazy val outgoing: Map[String, GraphRepr.Relation] = Map("pages" -> PageListRepr)
+ lazy val fields: Map[String, GraphRepr.Property] = Map()
+ // TODO =========================================================================================================
+ lazy val outgoing: Map[String, GraphRepr.Relation] = ??? /*Map(
+ "author" -> GraphRepr.Node.Optional(Author.AuthorRepr),
+ "pages" -> PageListRepr,
+ "meta" -> Meta.MetaRepr
+ )*/
  }
 
  implicit def pagesSchema: Schema.Aux[List[Page], PageListRepr.type] = Schema.defineFor[List[Page]](PageListRepr)
@@ -79,4 +87,18 @@ object Page {
  lazy val outgoing: Map[String, GraphRepr.Relation] = Map()
  }
  implicit def pageSchema: Schema.Aux[Page, PageRepr.type] = Schema.defineFor[Page](PageRepr)
+}
+
+object Meta {
+ object MetaRepr extends GraphRepr.Node {
+ type Labels = Witness.`"Meta"`.T :: HNil
+ type Fields = Witness.`'isbn`.Field[GraphRepr.Property.Aux[String]] :: HNil
+ type Outgoing = HNil
+ val Labels: Labels = "Meta".narrow :: HNil
+ val Fields: Fields = 'isbn ->> GraphRepr.Property[String] :: HNil
+ val Outgoing: Outgoing = HNil
+ val labels: List[String] = List("Meta")
+ val fields: Map[String, GraphRepr.Property] = Map("isbn" -> GraphRepr.Property[String])
+ val outgoing: Map[String, GraphRepr.Relation] = Map()
+ }
 }