PHP Expression Language

The purpose of this library is to provide a common base for an PHP Expression Language.

This is not really a creative library since it burrows almost all the code from the great JMSSecurityExtraBundle which already defines more or less such a base for a powerful EL (Expression Language).

The idea is to take this code outside of the Johannes's bundle and to standardize it.

Simple usage

$compiler = newExpressionCompiler();
$evaluator = eval($compiler->compileExpression(newExpression("date.format(format)")));
$context = array(
'date' => new \DateTime(),
'format' => 'Y',
);
$result = $evaluator($context);
echo$result; // 2013

Adding a custom function compiler

The isNumber() function expression:

1. First you need to create a compiler for your function

   <?phpnamespaceMy\Expression\Compiler\Func;
   usePel\Expression\Compiler\Func\FunctionCompilerInterface;
   usePel\Expression\ExpressionCompiler;
   usePel\Expression\Ast\FunctionExpression;
   usePel\Exception\RuntimeException;
   class IsNumberFunctionCompiler implements FunctionCompilerInterface
   {
   publicfunctiongetName()
   {
   return'isNumber';
   }
   publicfunctioncompilePreconditions(ExpressionCompiler$compiler, FunctionExpression$function)
   {
   if (1 !== count($function->args)) {
   thrownewRuntimeException(sprintf('The isNumber() function expects exactly one argument, but got "%s".', var_export($function->args, true)));
   }
   }
   publicfunctioncompile(ExpressionCompiler$compiler, FunctionExpression$function)
   {
   $compiler
   ->write("is_numeric(")
   ->compileInternal($function->args[0])
   ->write(")")
   ;
   }
   }

2. Next, after having instanciated the ExpressionCompiler, you just need to register your custom function compiler

   <?php$compiler = newExpressionCompiler();
   $compiler->addFunctionCompiler(newIsNumberFunctionCompiler());
   $evaluator = eval($compiler->compileExpression(newExpression("isNumber('1234')")));
   var_dump(call_user_func($evaluator, array()));
   // bool(true)$evaluator = eval($compiler->compileExpression(newExpression("isNumber('1234abc')")));
   var_dump(call_user_func($evaluator, array()));
   // bool(false)

License

This bundle is under the MIT license. See the complete license in library:

LICENSE