Basic merge compiler

app/Dom/Node.php

@@ -97,6 +97,24 @@ class Node implements \ArrayAccess, \Iterator
 		return $this->children;
 	}
 
+	/**
+	 * Attempt to find a child node by name.
+	 *
+	 * @param  string $name
+	 * @return ?Node
+	 */
+	public function getChildByName(string $name): ?Node
+	{
+		foreach ($this->children as $child)
+		{
+			if ($child->name == $name)
+			{
+				return $child;
+			}
+		}
+		return null;
+	}
+
 	/**
 	 * Add a node to this node's children.
 	 *
@@ -108,6 +126,48 @@ class Node implements \ArrayAccess, \Iterator
 		$this->children[] = $child;
 	}
 
+	/**
+	 * Remove a child node.
+	 *
+	 * @param  Node $child
+	 * @return void
+	 */
+	public function removeChild(Node $child): void
+	{
+		for ($i = 0; $i < sizeof($this->children); $i++)
+		{
+			if ($this->children[$i] === $child)
+			{
+				array_splice($this->children, $i, 1);
+				return;
+			}
+		}
+	}
+
+	public function isMap(): bool
+	{
+		foreach ($this->children as $child)
+		{
+			if (!$child->hasName())
+			{
+				return false;
+			}
+		}
+		return true;
+	}
+
+	public function isArray(): bool
+	{
+		foreach ($this->children as $child)
+		{
+			if ($child->hasName())
+			{
+				return false;
+			}
+		}
+		return true;
+	}
+
 	// ArrayAccess
 
 	public function offsetExists($offset): bool

app/Dom/NodeFunctionValue.php

@@ -47,4 +47,14 @@ class NodeFunctionValue extends NodeFunction
 	{
 		return $this->value;
 	}
+
+	public function isMap(): bool
+	{
+		return false;
+	}
+
+	public function isArray(): bool
+	{
+		return false;
+	}
 }

app/Dom/NodeValue.php

@@ -47,4 +47,14 @@ class NodeValue extends Node
 	{
 		return $this->value;
 	}
+
+	public function isMap(): bool
+	{
+		return false;
+	}
+
+	public function isArray(): bool
+	{
+		return false;
+	}
 }

app/Engine/Cfnpp.php

@@ -5,6 +5,8 @@ declare(strict_types=1);
 namespace App\Engine;
 
 use App\Dom\Document;
+use App\Dom\Node;
+use App\Dom\NodeValue;
 
 class Cfnpp implements ICompile
 {
@@ -18,7 +20,60 @@ class Cfnpp implements ICompile
 
 	public function compile(Document $document, IOptions $options): void
 	{
-		// noop
+		$this->compileNodes($this->document, $document);
+	}
+
+	protected function compileNodes(Node $original, Node $target): void
+	{
+		var_dump(get_class($original), get_class($target));
+		if ($target instanceof NodeValue)
+		{
+			if ($original instanceof NodeValue)
+			{
+				$original->setValue($target->getValue());
+			}
+			else
+			{
+				$parent = $original->getParent();
+				$parent->removeChild($original);
+				$parent->addChild($target);
+			}
+		}
+		// TODO: Add nodefunctions
+		elseif ($target instanceof Node)
+		{
+			// if they're both maps, add/overwrite by name
+			if ($target->isMap() && $original->isMap())
+			{
+				foreach ($target as $target_child)
+				{
+					$orig_child = $original->getChildByName($target_child->getName());
+					if (!isset($orig_child))
+					{
+						$original->addChild($target_child);
+					}
+					else
+					{
+						$this->compileNodes($orig_child, $target_child);
+					}
+				}
+			}
+			// if they're both arrays, append
+			elseif ($target->isArray() && $original->isArray())
+			{
+				foreach ($target as $child)
+				{
+					$original->addChild($child);
+				}
+			}
+			// if there's a mismatch, replace
+			else
+			{
+				$parent = $original->getParent();
+				$parent->removeChild($original);
+				$parent->addChild($target);
+			}
+		}
 	}
 
 	public function getDocument(): Document

app/Engine/CfnppOptions.php

@@ -0,0 +1,9 @@
+<?php
+
+declare(strict_types=1);
+
+namespace App\Engine;
+
+class CfnppOptions implements IOptions
+{
+}

app/Engine/Engine.php

@@ -64,7 +64,8 @@ class Engine
 
 	public function compileDocument(\App\Dom\Document $document, IOptions $options): Engine
 	{
-		return $this->compile->compile($document, $options);
+		$this->compile->compile($document, $options);
+		return $this;
 	}
 
 	public function getOutputDocument(): \App\Dom\Document