[gettalong]

I'm not a lawyer but I think you mistaken in this regard. One indication for this is that otherwise some major companies would have problems.

For example, the GPL FAQ has the following part in the FAQ item title "What is the difference between an 'aggregate' and other kinds of 'modified versions'?" (https://www.gnu.org/licenses/gpl-faq.en.html#MereAggregation):

> If the modules are included in the same executable file, they are definitely combined in one program. If modules are designed to run linked together in a shared address space, that almost surely means combining them into one program.

A combined work needs to be distributed under the AGPL, an aggregated work does not. Since Ruby is interpreted the code of HexaPDF loaded from the application would run in the same address space and thus it would be a combined work.

The following two links are also relevant: https://opensource.stackexchange.com/questions/5003/agplv3-s... and https://opensource.stackexchange.com/questions/5010/can-i-us...

[pabs3]

Just add an AGPL command-line interface, or a daemon wrapping the library and you have a process boundary. That doesn't necessarily create a derivative work boundary, but it probably would if it is generic enough to be useful to everyone.

[gettalong]

Yes, creating a binary and calling that would circumvent the AGPL. But then everything will be more complex and slower.

Also, doing this extra work and developing the binary is probably more expensive than just buying a commercial license.