Copyright law cannot be used to stop someone copying a programming language, a top EU lawyer has said.
Yves Bot, advocate general at the Court of Justice of the European Union (CJEU, formerly the ECJ), said on Tuesday that copyright also did not protect the functions of a program from being copied. The CJEU still needs to make a full judgment on the matter, based on Bot's advice.
The CJEU's guidance was for the benefit of the UK High Court, which asked for it in July 2010 in regards to a case between the SAS Institute, which makes various data analysis and processing software, and a smaller company called World Programming Limited (WPL).
SAS programs have to be written in the SAS Language, and those writing such applications need to get a licence from the company to do so. This has led to an entrenched customer base that has made a considerable investment in using the language, so WPL came up with an emulator that would be able to run SAS programs.
Although existing UK case law said it was not a copyright infringement to create such an emulator, SAS took its case to the High Court. Mr Justice Arnold referred the matter to the ECJ, saying guidance was required on three points.
On Tuesday, Bot confirmed that the functionalities of a computer program are not eligible for copyright protection, as they are "similar to ideas".
"That is why there may be a number of computer programs offering the same functionalities," the CJEU quoted Bot as saying. "Thus, if it were accepted that a functionality of a computer program can be protected as such, that would amount to making it possible to monopolise ideas, to the detriment of technological progress and industrial development."
Bot said copyright would provide protection if WPL had actually copied a substantial part of SAS's source code. Arnold's original ruling had pointed out that there was no evidence of this happening, although he did find WPL had breached copyright by copying much of the SAS manuals into its own.
Programming languages can themselves also not be protected by copyright, Bot confirmed. He compared programming languages to the language used by the author of a novel, and said they were "the means which permits expression to be given, not the expression itself".
Arnold had also asked the CJEU/ECJ to confirm that "copyright in computer programs does not protect interfaces from being copied where this can be achieved without decompiling the object code".
"Subject to two conditions, the holder of a licence to use a computer program may, without the author's authorisation, reproduce the program code or translate the form of the code of a data format in that program so as to write, in his own computer program, a source code which reads and writes that data format," the CJEU quoted Bot as saying.
These two conditions are that the operation has to be "absolutely indispensable" for achieving interoperability, and again that it "must not have the effect of enabling the licensee to recopy the code of the computer program in his own program".
Get the latest technology news and analysis, blogs and reviews delivered directly to your inbox with ZDNet UK's newsletters.