OpenType Debugging Hell...

André G. Isaak

So I just spent many hours trying to figure out why I was getting a fatal error when trying to compile what should have been relatively simple OpenType code in FontLab 5. Usually FontLab at least gives you a hint with a line number, but no such luck in this case.

I double-checked every semicolon, every set of brackets, etc. until I was completely dyslexic.

I eventually stumbled upon the error, and I’m rather surprised that I did because it was one I would never have thought of: I’d given the glyph at uni2316 the working name “position”, which the compiler was interpreting as a command rather than a glyph name. Of course, like most normal people I normally use ‘pos’ rather than ‘position’ and was surprised that I even remembered that this was a reserved word, particularly given that this only showed up in a class definition rather than in the code panel itself.

Does anyone know if there is a comprehensive list of reserved words used by AFDKO/FontLab? I’ve been unable to find one.

George Thomas

https://rawgit.com/adobe-type-tools/afdko/master/afdko/Technical Documentation/OpenTypeFeatureFileSpecification.html#2.c

André G. Isaak

¡Gracias!

I'd even scanned through that very same document looking for the term 'reserved'. Apparently I'm not very observant.

Kent Lew

Here is a slightly prettier version, with CSS. https://www.adobe.com/devnet/opentype/afdko/topic_feature_file_syntax.html

But unfortunately, Adobe has not maintained it at the latest document version. Latest is 1.21 (George’s link). This one is v 1.19.

George Thomas

I don't think it is there, but in my mind keyword would carry the same meaning.

André G. Isaak

I don't think it is there, but in my mind keyword would carry the same meaning.

Quite right, but my browser’s search function isn’t quite that clever.