Update fn::if to use new expression parser and generate conditions where appropriate

app/Cfnpp/Functions.php

@@ -16,6 +16,13 @@ use App\Dom\NodeFunctionValue;
  */
 class Functions
 {
+	/**
+	 * For now, generate incremental condition names.
+	 * @todo
+	 * @var int
+	 */
+	public static $condition_idx = 0;
+
 	/**
 	 * cfnpp compiler.
 	 * @var Compiler
@@ -149,26 +156,42 @@ class Functions
 		$if_true = $nodes[1];
 		$if_false = sizeof($nodes) == 3 ? $nodes[2] : null;
 
-		$parser = new \App\Cfnpp\Expression\Parser();
-		$expression = $parser->parse($condition->getValue());
-		$result = $expression->evaluate($this->options->getVariables());
+		$expression = new \App\Cfnpp\Expression\Expression($condition->getValue(), $this->options);
 
-		if (is_array($result))
+		// We need a single resulting node as a final value either as a scalar or
+		// if we want to convert to cloudformation.
+		if ($expression->count() > 1)
 		{
 			throw new \Exception('!if expression must evaluate down to a single value: '.$condition->getValue());
 		}
 
-		if ($result)
+		if ($expression->isComplete())
 		{
-			$if_true->setName($node->hasName() ? $node->getName() : null);
-			return $if_true;
+			// We know the final result, we can resolve this directly.
+			if ($expression->getValue())
+			{
+				$if_true->setName($node->hasName() ? $node->getName() : null);
+				return $if_true;
+			}
+			elseif (isset($if_false))
+			{
+				$if_false->setName($node->hasName() ? $node->getName() : null);
+				return $if_false;
+			}
+			return null;
 		}
 
-		if (isset($if_false))
-		{
-			$if_false->setName($node->hasName() ? $node->getName() : null);
-		}
-		return $if_false;
+		// Create condition
+		// Generate Cfn Fn::If
+		$condition_name = 'Condition'.(static::$condition_idx++);
+		$this->compiler->addCondition($condition_name, Node::fromPhp($expression->toCloudformation()));
+
+		$n_orig = new Node(null, $node->hasName() ? $node->getName() : null);
+		$n_if = new Node($n_orig, 'Fn::If');
+		$n_if->addChild(new NodeValue($n_if, null, $condition_name));
+		$n_if->addChild($if_true);
+		$n_if->addChild($if_false);
+		return $n_if;
 	}
 
 	/**
@@ -194,5 +217,4 @@ class Functions
 
 		return $result;
 	}
-
 }