1 files changed, 74 insertions, 0 deletions
diff --git a/yamlesque/src/Writer.scala b/yamlesque/src/Writer.scala
new file mode 100644
index 0000000..e387ef9
--- /dev/null
+++ b/yamlesque/src/Writer.scala
@@ -0,0 +1,74 @@
+package yamlesque
+
+object Writer {
+
+  def write(nodes: Iterable[Node]): String = {
+    val buffer = new StringBuilder
+    write(nodes, buffer)
+    buffer.result()
+  }
+  def write(nodes: Iterable[Node], buffer: StringBuilder): Unit = {
+    val it = nodes.iterator
+    while (it.hasNext) {
+      writeCompact(buffer, true, 0, it.next())
+      if (it.hasNext) buffer ++= "---\n"
+    }
+  }
+
+  private def writeCompact(
+      buffer: StringBuilder,
+      startOfLine: Boolean,
+      indent: Int,
+      node: Node
+  ): Unit = {
+    node match {
+      case Null =>
+        buffer ++= "null\n"
+      case Bool(true) =>
+        buffer ++= "true\n"
+      case Bool(false) =>
+        buffer ++= "false\n"
+      case Num(num) =>
+        buffer ++= num.toString
+        buffer += '\n'
+      case Str(value) =>
+        buffer ++= value
+        buffer += '\n'
+      case Arr(values) =>
+        var doIndent = startOfLine
+        for (item <- values) {
+          if (doIndent) {
+            buffer ++= "  " * indent
+          }
+          doIndent = true
+          item match {
+            case Arr(_) =>
+              buffer ++= "-\n"
+              writeCompact(buffer, true, indent + 1, item)
+            case _ =>
+              buffer ++= "- "
+              writeCompact(buffer, false, indent + 1, item)
+          }
+        }
+      case Obj(values) =>
+        var doIndent = startOfLine
+        for ((key, value) <- values) {
+          if (doIndent) {
+            buffer ++= "  " * indent
+          }
+          doIndent = true
+
+          buffer ++= key
+          value match {
+            case Str(_) | Bool(_) | Num(_) | Null =>
+              buffer ++= ": "
+              writeCompact(buffer, false, indent, value)
+            case _ =>
+              buffer ++= ":\n"
+              writeCompact(buffer, true, indent + 1, value)
+          }
+        }
+    }
+  }
+
+}