src/StringReader.php
public function readOne()
    {
        if ($this->pos <= $this->max) {
            $value = $this->string[$this->pos];
            $this->pos += 1;
        } else {
            $value = null;
        }

        return $value;
    }
public function readOne()
    {
        if ($this->pos <= $this->max) {
            $value = $this->string[$this->pos];
            $this->pos += 1;
        } else {
            $value = null;
        }

        return $value;
    }
Read the next character from the supplied string.
Return null when we have run out of characters.