laravel syntax error unexpected '.' on attempted concatenation of string in model - php

Question

I am working in Laravel, and I have a model Group where I have rules for validation. I am attempting to have a unique name_group but only for the given year. The code below works perfectly if I replace .$this->year_groups with 2016 for example. But when I try to add the actual year of the group to be created by concatenating .this->year_groups, I get a syntax error:
Symfony \ Component \ Debug \ Exception \ FatalErrorException syntax error, unexpected '.', expecting ')'
I have looked at many examples and they (seem) to be written this way, and I just can't find what is wrong. I am thinking perhaps it has something to do that this is in an array...?
Any help would be greatly appreciated!!
Model:
<?php
use Illuminate\Auth\UserTrait;
use Illuminate\Auth\UserInterface;
use Illuminate\Auth\Reminders\RemindableTrait;
use Illuminate\Auth\Reminders\RemindableInterface;
class Group extends Eloquent implements UserInterface,RemindableInterface
{
use UserTrait, RemindableTrait;
protected $table = 'groups';
protected $primaryKey = "id_groups";
protected $fillable = array('name_groups','year_groups','grados_id_grados');
//The error is in the following $rules
public static $rules = array(
'year_groups'=> 'required',
'name_groups'=> 'required|unique:groups,name_groups,NULL, id_groups,year_groups,' . $this->year_groups,
'grados_id_grados' => 'required'
);
public function grado()
{
return $this->belongsTo('Grado','grados_id_grados');
}
public function students()
{
return $this->belongsToMany('Student','group_student','id_group','id_student')->withTimestamps();
}
public function teachers()
{
return $this->belongsToMany('Teacher','group_subject_teacher','id_group','id_teacher')->withPivot('id_subject','year_groups')->withTimestamps();
}
}
In the Controller I call validation from the store method:
public function store()
{
$input = Input::all();
$validation = Validator::make($input, Group::$rules);
if($validation->passes()){
$group = new Group;
$group->name_groups = Input::get('name_groups');
$group->year_groups = Input::get('year_groups');
$group->grados_id_grados = Input::get('grados_id_grados');
$group->save();
}
}

Answer 1

Looking your code, it seems $rules is variable or property of class. The way you are assigning values to property are wrong, so it is throwing error. Look below code and arrange your code accordingly:-
class anyClass {
private $year_groups = "2016";
public $rules = [];
public function __construct(){
$this->rules = array(
'year_groups'=> 'required',
'name_groups'=> 'required|unique:groups,name_groups,NULL, id_groups,year_groups,'.$this->year_groups,
'grados_id_grados' => 'required'
);
}
}

Answer 2

I changed Model to:
use Illuminate\Auth\UserTrait;
use Illuminate\Auth\UserInterface;
use Illuminate\Auth\Reminders\RemindableTrait;
use Illuminate\Auth\Reminders\RemindableInterface;
class Group extends Eloquent implements UserInterface,RemindableInterface
{
use UserTrait, RemindableTrait;
protected $table = 'groups';
protected $primaryKey = "id_groups";
protected $fillable = array('name_groups','year_groups','grados_id_grados');
//This part I changed
public static $rules = [];
public static function _construct($year){
$rules = array(
'year_groups'=> 'required',
'name_groups'=> 'required|unique:groups,name_groups,NULL, id_groups,year_groups,' . $year,
'grados_id_grados' => 'required'
);
return $rules;
}
public function grado()
{
return $this->belongsTo('Grado','grados_id_grados');
}
public function students()
{
return $this->belongsToMany('Student','group_student','id_group','id_student')->withTimestamps();
}
public function teachers()
{
return $this->belongsToMany('Teacher','group_subject_teacher','id_group','id_teacher')->withPivot('id_subject','year_groups')->withTimestamps();
}
}
Then in Controller:
public function store()
{
$input = Input::all();
$validation = Validator::make($input, Group::_construct(Input::get('year_groups')));
if($validation->passes()){
$group = new Group;
$group->name_groups = Input::get('name_groups');
$group->year_groups = Input::get('year_groups');
$group->grados_id_grados = Input::get('grados_id_grados');
$group->save();
}
}