Add concat/select operators

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());
 		}
 	}
 }