Question

How come a simple instantiation doesn’t work? I have been doing the same method to all of the classes I created/instantiated but this is the only one that’s giving me this kind of error.

 Fatal error: Call to a member function validate_fname_and_lname() on a non-object in /homepages/......../Validate.php on line 23

Here’s my code:

//Class Validate
<?php

require_once 'RegExp.php';

$myRegExp = new RegExp();

class Validate 
{
    //Sends each entry to corresponding RegExp function with appropriate regular expression
    function validate_form($un, $fname)
    {
        $err_counter = 0;

        if(!$this->myRegExp->validate_fname_and_lname($fname))
        {
            $error_identifier .= 'firstName+';
            ++$err_counter;
        }
    }
}


//Class RegExp
<?php

class RegExp 
{
    function validate_fname_and_lname($flname)
    {
        return preg_match("/[a-zA-Z' ']{2,}/", $flname);
    }
}

Answer 1

I think you are trying to access the global $myRegExp from within object scope.

You should probaby add a constructor to your validator:

public function __construct($re)
{
    $this->myRegExp = $re;
}

And then instantiate your Validator like this:
$validator = new Validate($myRegExp);

And you should declare a member variable ‘myRegExp’ in your Validate class.

---

And on a side note: I think you should rethink your design. If I were you I’d create an interface:

interface IValidator
{
    public function valid($input);
}

Let your specific regex classes implement that interface:

class ValidateFnameAndLname implements IValidator
{
    function valid($flname)
    {
        return preg_match("/[a-zA-Z' ']{2,}/", $flname);
    }
}

And construct your Validate class like this:

class Validate 
{
    protected $myRegExp;
    public function __construct(IValidator $validator)
    {
        $this->myRegExp = $validator;
    }
    //Sends each entry to corresponding RegExp function with appropriate regular expression
    function validate_form($un, $fname)
    {
        $err_counter = 0;

        if(!$this->myRegExp->valid($fname))
        {
            $error_identifier .= 'firstName+';
            ++$err_counter;
        }
    }
}

Then you are on your way to get a more coherent design.