Track parameters like variables

Not in love with this. Cannot use !functions in variables/parameters block because they're grabbed before being compiled.

app/Engine/CfnppOptions.php

@@ -18,9 +18,17 @@ class CfnppOptions implements IOptions
 	 */
 	protected $variables;
 
+	/**
+	 * Store the parameters we send to cloudformation.
+	 *
+	 * @var array<string,mixed>
+	 */
+	protected $parameters;
+
 	public function __construct()
 	{
 		$this->variables = [];
+		$this->parameters = [];
 	}
 
 	/**
@@ -82,4 +90,64 @@ class CfnppOptions implements IOptions
 	{
 		return isset($this->variables[$name]);
 	}
+
+	/**
+	 * Set all parameters.
+	 *
+	 * @param  array<string,mixed> $parameters
+	 * @return void
+	 */
+	public function setParameters(array $parameters): void
+	{
+		$this->parameters = $parameters;
+	}
+
+	/**
+	 * Retrieve all parameters.
+	 *
+	 * @return array<string,mixed>
+	 */
+	public function getParameters(): array
+	{
+		return $this->parameters;
+	}
+
+	/**
+	 * Retrieve the value of a single parameter.
+	 *
+	 * @param  string     $name
+	 * @throws \Exception if parameter does not exist
+	 * @return mixed
+	 */
+	public function getParameter(string $name)
+	{
+		if (!isset($this->parameters[$name]))
+		{
+			throw new \Exception('Unset parameter: '.$name);
+		}
+		return $this->parameters[$name];
+	}
+
+	/**
+	 * Set a single parameter.
+	 *
+	 * @param  string $name
+	 * @param  mixed  $value
+	 * @return void
+	 */
+	public function setParameter(string $name, $value): void
+	{
+		$this->parameters[$name] = $value;
+	}
+
+	/**
+	 * Check if a parameter exists.
+	 *
+	 * @param  string $name
+	 * @return bool
+	 */
+	public function hasParameter(string $name): bool
+	{
+		return isset($this->parameters[$name]);
+	}
 }

app/Engine/Engine.php

@@ -44,6 +44,7 @@ class Engine
 	 * Process a domdocument, applying some higher level operations such as
 	 * stacking documents.
 	 *
+	 * @todo break all this stuff out
 	 * @param  string   $input_file
 	 * @param  IOptions $options
 	 * @return string
@@ -78,8 +79,9 @@ class Engine
 			}
 		}
 
-		// Go through and load all the variables
+		// Go through and load all the variables and parameters
 		$variables = [];
+		$parameters = [];
 		for ($i = 0; $i < sizeof($files); $i++)
 		{
 			$file_variables = [];
@@ -95,6 +97,20 @@ class Engine
 			{
 				$variables[$k] = $v;
 			}
+
+			$file_parameters = [];
+			try
+			{
+				$file_parameters = $documents[$files[$i]]->getMeta('parameters');
+			}
+			catch (\Exception $ex)
+			{
+			}
+
+			foreach ($file_parameters as $k => $v)
+			{
+				$parameters[$k] = $v;
+			}
 		}
 
 		foreach ($variables as $k => $v)
@@ -105,6 +121,14 @@ class Engine
 			}
 		}
 
+		foreach ($parameters as $k => $v)
+		{
+			if (!$options->hasParameter($k))
+			{
+				$options->setParameter($k, $v);
+			}
+		}
+
 		// Now actually process all the documents
 		for ($i = 0; $i < sizeof($files); $i++)
 		{

app/Engine/IOptions.php

@@ -50,4 +50,44 @@ interface IOptions
 	 * @return bool
 	 */
 	public function hasVariable(string $name): bool;
+
+	/**
+	 * Set parameters to send to cloudformation.
+	 *
+	 * @param  array<string, mixed> $parameters
+	 * @return void
+	 */
+	public function setParameters(array $parameters): void;
+
+	/**
+	 * Retrieve all parameters set.
+	 *
+	 * @return array<string,mixed>
+	 */
+	public function getParameters(): array;
+
+	/**
+	 * Retrieve the value of a single parameter.
+	 *
+	 * @param  string $name
+	 * @return mixed
+	 */
+	public function getParameter(string $name);
+
+	/**
+	 * Set a single parameter.
+	 *
+	 * @param  string $name
+	 * @param  mixed  $value
+	 * @return void
+	 */
+	public function setParameter(string $name, $value): void;
+
+	/**
+	 * Check if a parameter exists.
+	 *
+	 * @param  string $name
+	 * @return bool
+	 */
+	public function hasParameter(string $name): bool;
 }