public String toString(Format f) {
        StringBuilder b = new StringBuilder();
        String header = "";
        String body;
        switch (f) {
            case GHG:
            case JEKYLL_MD:
            case JEKYLL_HTML:
                this.variables.toString(f, b);
                header = b.toString();
                b = new StringBuilder();
                break;
        }
        for (Topic t : this.topics) {
            b.append("\n");
            t.toString(f, b);
        }
        body = b.toString();
        switch (f) {
            case HTML:
            case JEKYLL_HTML:
                body = body;//TODO: CONVERT TO HTML HERE!!!!
        }

        switch (f) {
            case GHG:
            case JEKYLL_MD:
            case JEKYLL_HTML:
                return header + body;
            default:
                return body;
        }
    }