Bugfix: Fix processing order for functions -- deepest nodes first

This is the default merge behaviour, but simplifies using !replace because passing in a var that happens to evaluate to a scalar won't cause an issue anymore

app/Cfnpp/Compiler.php

@@ -123,15 +123,6 @@ class Compiler implements \App\Engine\ICompile
 		$this->pass_2($document, $options);
 
 		return $this->document;
-		// Process each passed document
-		/*
-		foreach ($documents as $next_document)
-		{
-			$this->runMergeFunctions($document, $next_document);
-			$this->merge($document, $next_document);
-			$this->runFunctions($document);
-		}
-		 */
 	}
 
 	/**
@@ -302,14 +293,12 @@ class Compiler implements \App\Engine\ICompile
 			{
 				$variables[] = $node->getValue();
 			}
-			/*
-			// TODO: Reimplement
 			elseif ($node instanceof NodeFunctionValue &&
 				$node->getName() == 'expr')
 			{
 				$expression = new \App\Cfnpp\Expression\Expression($node->getValue());
 				$variables = array_merge($variables, $expression->getReferencedVariables());
-			}*/
+			}
 		}
 
 		return $variables;
@@ -454,6 +443,12 @@ class Compiler implements \App\Engine\ICompile
 	 */
 	protected function runFunctions(Node $node): void
 	{
+		$children = $node->getChildren();
+		foreach ($children as $child)
+		{
+			$this->runFunctions($child);
+		}
+
 		if ($node->isFunctionParent() && isset($this->functions[$node[0]->getName()]))
 		{
 			$function_node = $node[0];
@@ -471,12 +466,6 @@ class Compiler implements \App\Engine\ICompile
 				return;
 			}
 		}
-
-		$children = $node->getChildren();
-		foreach ($children as $child)
-		{
-			$this->runFunctions($child);
-		}
 	}
 
 	/**

app/Cfnpp/Expression/Expression.php

@@ -20,6 +20,7 @@ class Expression
 	 * @var string[]
 	 */
 	public const TOKEN_TYPES = [
+		Token\BooleanLiteral::class,
 		Token\NumericLiteral::class,
 		Token\OperatorUnary::class,
 		Token\OperatorBinary::class,

app/Cfnpp/Expression/Token/BooleanLiteral.php

@@ -0,0 +1,75 @@
+<?php
+
+declare(strict_types=1);
+
+namespace App\Cfnpp\Expression\Token;
+
+use App\Cfnpp\Expression\Token;
+use App\Cfnpp\Expression\TokenLiteral;
+
+/**
+ * A boolean literal (true/false).
+ *
+ * @author Adam Pippin <hello@adampippin.ca>
+ */
+class BooleanLiteral extends TokenLiteral
+{
+	/**
+	 * Value of this literal.
+	 * @var bool
+	 */
+	protected $value;
+
+	/**
+	 * New boolean literal.
+	 *
+	 * @param bool $value
+	 */
+	public function __construct(bool $value)
+	{
+		$this->value = $value;
+	}
+
+	/**
+	 * Get the value of this literal.
+	 *
+	 * @return bool
+	 */
+	public function getValue(): bool
+	{
+		return $this->value;
+	}
+
+	public static function isToken(string $stream): bool
+	{
+		return
+			(strlen($stream) >= 4 && strtolower(substr($stream, 0, 4)) == 'true') ||
+			(strlen($stream) >= 5 && strtolower(substr($stream, 0, 5)) == 'false');
+	}
+
+	public static function getToken(string &$stream): Token
+	{
+		if (strlen($stream) >= 4 && strtolower(substr($stream, 0, 4)) == 'true')
+		{
+			$stream = substr($stream, 4);
+			return new BooleanLiteral(true);
+		}
+		elseif (strlen($stream) >= 5 && strtolower(substr($stream, 0, 5)) == 'false')
+		{
+			$stream = substr($stream, 5);
+			return new BooleanLiteral(false);
+		}
+		throw new \Exception('Unparseable boolean');
+	}
+
+	/**
+	 * Get the value of this token.
+	 *
+	 * @param  ?\App\Util\GraphNode[]                $arguments
+	 * @return \App\Util\GraphNode|Token|scalar|null
+	 */
+	public function execute(?array $arguments = null)
+	{
+		return $this->getValue();
+	}
+}

app/Cfnpp/Expression/Token/OperatorBinary.php

@@ -22,7 +22,9 @@ class OperatorBinary extends TokenBinary implements ICloudformationNative
 	public const OPERATORS = [
 		'and',
 		'or',
-		'eq'
+		'eq',
+		'concat',
+		'select'
 	];
 
 	/**
@@ -147,8 +149,32 @@ class OperatorBinary extends TokenBinary implements ICloudformationNative
 
 				return null;
 
+			case 'concat':
+				if (is_scalar($value1) && is_scalar($value2))
+				{
+					return $value2.$value1;
+				}
+				elseif ($value1 instanceof Parameter && is_scalar($value2) && empty($value2))
+				{
+					return $value1;
+				}
+				elseif ($value2 instanceof Parameter && is_scalar($value1) && empty($value1))
+				{
+					return $value2;
+				}
+
+				return null;
+
+			case 'select':
+				if (is_scalar($value1) && is_array($value2))
+				{
+					return $value2[$value1];
+				}
+
+				return null;
+
 			default:
-				throw new \Exception('Missing implementation for unary operator: '.$this->getOperator());
+				throw new \Exception('Missing implementation for binary operator: '.$this->getOperator());
 		}
 	}
 
@@ -174,8 +200,12 @@ class OperatorBinary extends TokenBinary implements ICloudformationNative
 				return ['Fn::Or' => [$value1, $value2]];
 			case 'eq':
 				return ['Fn::Equals' => [$value1, $value2]];
+			case 'concat':
+				return ['Fn::Join' => ['', [$value2, $value1]]];
+			case 'select':
+				return ['Fn::Select' => [$value1, $value2]];
 			default:
-				throw new \Exception('Missing implementation for unary operator: '.$this->getOperator());
+				throw new \Exception('Operator cannot be applied to parameters: '.$this->getOperator());
 		}
 	}
 }

app/Cfnpp/Functions.php

@@ -83,7 +83,10 @@ class Functions
 	 */
 	public function mf_replace(Node $original, Node $target, NodeFunction $function): ?Node
 	{
-		// TODO: Deal with nodefunctionvalue
+		if ($function instanceof NodeFunctionValue)
+		{
+			return new NodeValue(null, $target->hasName() ? $target->getName() : null, $function->getValue());
+		}
 
 		$replacement = new Node(null, $target->hasName() ? $target->getName() : null);
 		$replacement->setChildren($function->getChildren());
@@ -212,23 +215,38 @@ class Functions
 	 * @param  NodeFunction $function
 	 * @return ?Node
 	 */
-	/*
-	 * TODO: Reimplement
 	public function f_expr(Node $node, NodeFunction $function): ?Node
 	{
 		if (!($function instanceof NodeFunctionValue))
 		{
-			throw new \Exception('!if requires scalar argument');
+			throw new \Exception('!expr requires scalar argument');
 		}
 
-		$parser = new \App\Cfnpp\Expression\Parser();
-		$expression = $parser->parse($function->getValue());
-		$result = $expression->evaluate($this->options->getVariables());
+		$expression = new \App\Cfnpp\Expression\Expression($function->getValue(), $this->options);
 
-		$result = Node::fromPhp($result);
-		$result->setName($node->hasName() ? $node->getName() : null);
+		if ($expression->isComplete())
+		{
+			// If we computed a final value/set of values, we can just insert those
+			// directly.
+			if ($expression->count() == 1)
+			{
+				$solution_node = Node::fromPhp($expression->getValue());
+			}
+			else
+			{
+				$solution_node = Node::fromPhp($expression->toArray());
+			}
+		}
+		else
+		{
+			// Otherwise let's convert it to cfn intrinsics
+			$solution_node = Node::fromPhp($expression->toCloudformation());
+		}
 
-		return $result;
+		if ($node->hasName())
+		{
+			$solution_node->setName($node->getName());
+		}
+		return $solution_node;
 	}
-	 */
 }