Merge pull request #5 from tarao/pluggable-placeholders

Make placeholders pluggable.

src/main/scala/com/github/tarao/slickjdbc/interpolation/Interpolation.scala

@@ -27,28 +27,3 @@ class SimpleString(value: String) extends Literal {
   override def toString = value
 }
 case class TableName(name: String) extends SimpleString(name)
-
-class Placeholders(val value: Any, val topLevel: Boolean = true)
-    extends Literal {
-  def toCompleteString: String = {
-    def rec(v: Any) = new Placeholders(v, false).toString
-    val (single, elements) = value match {
-      case s: Tuple1[_] => (false, Iterator.single(rec(s._1)))
-      case p: Product if p.productArity <= 0 =>
-        throw new java.sql.SQLException("No value to bind for " + p)
-      case p: Product => (p.productArity == 1, p.productIterator.map(rec))
-      case l: NonEmpty[_] => (false, l.toSeq.map(rec))
-      case _ => (true, Iterator.single(new Placeholders(this, false) {
-        override def toCompleteString: String = "?"
-      }.toString) )
-    }
-    if (single) elements.toSeq.head
-    else s"""(${stripParen(elements.mkString(", "))})"""
-  }
-  private def stripParen(str: String) = str.stripPrefix("(").stripSuffix(")")
-  private def dropLast(str: String) = str.stripSuffix("?")
-  override def toString = {
-    val s = toCompleteString
-    if (topLevel) dropLast(stripParen(s)) else s
-  }
-}

src/main/scala/com/github/tarao/slickjdbc/interpolation/MacroTreeBuilder.scala

@@ -42,6 +42,10 @@ private[interpolation] class MacroTreeBuilder(val c: Context) {
     tq"""$interpolation.${TypeName("CheckOption")}"""
   private def checkParameter(required: Type, base: Tree = CheckParameter) =
     q"implicitly[$base[$required]]"
+  private val ToPlaceholder =
+    tq"""$interpolation.${TypeName("ToPlaceholder")}"""
+  private def toPlaceholder(target: Type, base: Tree = ToPlaceholder) =
+    q"implicitly[$base[$target]]"
   private val Translators =
     tq"Traversable[$NS.query.Translator]"
 
@@ -119,7 +123,11 @@ private[interpolation] class MacroTreeBuilder(val c: Context) {
 
         mayCompleteParen(param, s) {
           // for "?, ?, ?, ..."
-          params.append(c.Expr(q"new $interpolation.Placeholders(${param})"))
+          params.append(c.Expr(q"""
+            ${toPlaceholder(param.actualType)}
+              .apply(${param})
+              .toTopLevelString
+          """))
           queryParts.append(q""" ${"#"} """)
           // for the last "?" (inserted by ActionBasedSQLInterpolation)
           params.append(param)

src/main/scala/com/github/tarao/slickjdbc/interpolation/Placeholder.scala

@@ -0,0 +1,27 @@
+package com.github.tarao
+package slickjdbc
+package interpolation
+
+class Placeholder extends Literal {
+  import Placeholder.{stripParen, dropLast}
+  def toSeq: Seq[Placeholder] = Seq(this)
+  def toTopLevelString: String = dropLast(stripParen(toString))
+  override def toString: String = "?"
+}
+object Placeholder {
+  private def stripParen(str: String) = str.stripPrefix("(").stripSuffix(")")
+  private def dropLast(str: String) = str.stripSuffix("?")
+
+  def apply(): Placeholder = new Placeholder
+  def repeat(n: Int): Seq[Placeholder] = (1 to n).map(_ => apply())
+
+  class Nested(children: Placeholder*) extends Placeholder {
+    override def toSeq: Seq[Placeholder] = children
+    override def toString: String =
+      s"""(${stripParen(children.map(_.toString).mkString(", "))})"""
+  }
+  object Nested {
+    def apply(children: Placeholder*): Nested = new Nested(children: _*)
+    def apply(n: Int): Nested = new Nested(Placeholder.repeat(n): _*)
+  }
+}

src/main/scala/com/github/tarao/slickjdbc/interpolation/SetParameter.scala

@@ -7,14 +7,23 @@ import scala.annotation.implicitNotFound
 import slick.jdbc.{SetParameter => SP, PositionedParameters}
 
 trait CompoundParameter {
-  implicit def createSetProduct[T](implicit
+  @inline implicit def createSetProduct[T](implicit
     check1: T <:< Product,
     check2: IsNotTuple[T]
   ): SP[T] = new SetProduct[T]
 
-  @inline implicit
-  def createSetList[T](implicit c: SP[T]): SetList[T, NonEmpty[T]] =
-    new SetList[T, NonEmpty[T]](c)
+  @inline implicit def createSetList[T](implicit
+    c: SP[T]
+  ): SP[NonEmpty[T]] = new SetList[T, NonEmpty[T]](c)
+
+  @inline implicit def productToPlaceholder[T](implicit
+    check1: T <:< Product,
+    check2: IsNotTuple[T]
+  ): ToPlaceholder[T] = new ToPlaceholder.FromProduct[T]
+
+  @inline implicit def listToPlaceholder[T](implicit
+    p: ToPlaceholder[T]
+  ): ToPlaceholder[NonEmpty[T]] = new ToPlaceholder.FromList[T, NonEmpty[T]](p)
 }
 object CompoundParameter extends CompoundParameter