<?php
namespace eMacros\Runtime\Symbol;
use eMacros\Applicable;
use eMacros\Scope;
use eMacros\GenericList;
class SymbolExists implements Applicable {
/**
* Checks if the given symbol exists on current environment
* Usage: (sym-exists "true") (sym-exists "_value")
* Returns: boolean
* (non-PHPdoc)
* @see \eMacros\Applicable::apply()
*/
public function apply(Scope $scope, GenericList $arguments) {
if (count($arguments) == 0) {
throw new \BadFunctionCallException("SymbolExists: No parameters found.");
}
$ref = $arguments[0]->evaluate($scope);
if (!is_string($ref) || empty($ref)) {
throw new \InvalidArgumentException("SymbolExists: Symbol must be specified as a non-empty string.");
}
return array_key_exists($ref, $scope->symbols);
}
}
?>
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