We have a software which supports scripting. One of our main competitors has a software which works in the same way.
I wonder if it is legal for our software to support their properiatery scripting language. We want to attract the users of other software by not needing to learn a new scripting language.
Can we at least have automated-converter from that language to our scripting language?
Assuming that you do not infringe or misappropriate any of the other company's intellectual property, I have a difficult time imagining that you will have done anything wrong by converting or interpreting scripts in the other company's language.
Disclaimer: This information does not constitute legal advice and does not establish an attorney-client relationship.
Please consult a lawyer. This is not easy to answer.
The recent Oracle / Google trial has shown that APIs are not protectable. But I would not go so far and say it is the same for the language of your competitor. The whole trial was pretty complicated and took long time. You best bet is to ask a lawyer if you want to do something like that.
In addition, asking for permission might be another option.
I see nothing wrong in this. Many software packages do this - read and write propriatory files. As long as the code is your own, then there should be no problem. Your competitors IR and copyright will be on their software.
Of course this does not stop them attempting to stop you, nor does it protect you from them making changes to their file format (scripting language etc) that breaks your code.