Pinq\Expressions\VariableExpression::update PHP Method

    public function update(Expression $name)
    {
        if ($this->name === $name) {
            return $this;
        }
        return new self($name);
    }

 public function walkVariable(VariableExpression $expression)
 {
     $name = $expression->getName();
     if ($name instanceof O\ValueExpression) {
         return $expression->update(O\Expression::value($this->prefix . $name->getValue()));
     }
     return $expression->update(O\Expression::binaryOperation(O\Expression::value($this->prefix), O\Operators\Binary::CONCATENATION, $name));
 }