Variable scope - php - Using variables from one function in another - php

Question

I am having trouble using a variable generated in one function, as a variable in a second function.
The Problem:
I get Notice: Undefined variable: parameter in the validate function, on the line:
$this->$methodName($item,$value,$parameter) OR $valid=false;
When the function call for splitRulesAndParameters is simply replaced with the code within the function, the problem goes away.
The Scenario:
The following two functions are both within the Validator class, the first, validate, makes use of the second, splitRulesAndParameters
Here is the validate function:
public function validate($data, $rules)
{
$valid= true;
foreach($rules as $item=>$ruleSet)
{
$ruleSetArray=explode('|',$ruleSet);
foreach($ruleSetArray as $rule)
{
$this->splitRulesAndParameters($rule);
$methodName='validate'.ucfirst($rule);
$value = isset($data[$item]) ? $data[$item] : NULL;
if(method_exists($this, $methodName))
{
$this->$methodName($item,$value,$parameter) OR $valid=false;
}
}
}
return $valid;
}
And here is the splitRulesAndParameters function
public function splitRulesAndParameters($rule)
{
$position = strpos($rule, ':');
if($position !==false)
{
$parameter = substr($rule,$position + 1);
$rule = substr($rule,0,$position);
}
else
{
$parameter='';
}
}

Answer 1

Seeing as the problem goes away if you "inline" the code in splitRulesAndParameters, I suspect the $parameters variable is used in that method. If so, simply have that method return the value of this variable, and assign it to a variable local to the validate method you've posted here:
$parameters = $this->splitRulesAndParameters($rule);
After adding this to the splitRulsAndParameters method:
return $parameters;
The method itself also modifies the $rule value. Again: this $rule variable is local to each method. It may have the same name, but the value is a copy. Any changes you make to $rule in splitRulesAndParameters is not reflected by $rule in your validate method. If I were you, I'd write:
public function splitRulesAndParameters($rule)
{
$position = strpos($rule, ':');
if($position !==false)
{
return array(
'parameter' => substr($rule, $position+1),
'rule' => substr($rule, 0, $position)
);
}
return array(
'parameter' => null,//no param == null, IMO, change to '' if you want
'rule' => $rule
);
}
Then, to change the variables in validate:
$split = $this->splitRulesAndParameters($rule);
$rule = $split['rule'];
$parameter = $split['parameter'];
That ought to do it.
Side-note:
You seem to be validating everything that needs validating, even if the first validation failed. If I were you, I'd change this fugly statement:
$this->$methodName($item,$value,$parameter) OR $valid=false;
To a more efficient:
if (!$this->{$methodName}($item, $value, $parameter))
return false;//if validation fails, return false
That stops any further valiation from being executed: if one value is invalid, then just stop there. To continue is pointless, because the data-set is not entirely valid anyway.
Bonus:
Using a colon to separate the method name, and some parameter(s) does allow you to specify multiple params, too, and it allows you to simplify the splitRulesAndParameters some more:
protected function splitRulesAndParameters($rule)
{
$all = explode(':', $rule);
return array(
'rule' => array_shift($all),//removes first element in array
'params' => $all//rest of the array
);
}
Tweak this a little to better suite your needs

Answer 2

You can't just use a variable from inside a function in another function. You have to return the variable $parameter. Add a return statement to the end of splitRulesAndParameters and store the result in a variable inside validate ($parameter = $this->spli...).

Answer 3

You actually have two problems here, because you change the &rule variable inside your function, but you are passing it by reference. So after the fucntion is done the $rule variable is the same as it was before.
The way to solve this in the manner you are doing it right now would be to change the function to:
public function splitRulesAndParameters(&$rule)
{
$position = strpos($rule, ':');
if($position !==false)
{
$parameter = substr($rule,$position + 1);
$rule = substr($rule,0,$position);
}
else
{
$parameter='';
}
return $parameter;
}
and change the line
$this->splitRulesAndParameters($rule);
to
$parameter = $this->splitRulesAndParameters($rule);