example.py

from flask import request, url_for


def modified_url(**new_args):
    args = request.view_args.copy()
    args.update(new_args)
    return url_for(request.endpoint, **args)


app.jinja_env.globals['modified_url'] = modified_url

gistfile1.mustache

<a href="{{ modified_url(page=2) }}">link to page 2</a>

not work for current gets

 args = request.args.copy()

can be okey