As described in an earlier post [1], I am looking at all the variables an external process could need. The problem I saw was a large growth of variables that express essentially the same idea, e.g. all the open files, but that are represented differently, e.g. by using ‘:’ as separator instead of ‘ ‘.
I have now solved the problem by using attributes. Each variable can register any number of attributes and set defaults, but the user can override them. To do that, I had to write a new stream tokenizer, as the old one wasn’t easy to use when quote/brace balancing was necessary. The new one, BalancingStreamTokenizer is fairly simple; arguably simpler than the original one. There is no distinction between ordinary characters, word characters, numbers, comments, and quotes. The tokenizer always returns a string.
However, it is possible to register keywords, which are a major replacement over the single-length “ordinary character” concept of Java’s StreamTokenizer. It is furthermore possible to register multi-character quotation symbols where the beginning and the end symbol do not have to match, e.g. /* and */ or ${ and }. Inside quotes, quotation marks are balanced, so a quotation will not cut off at the first matching ending quotation mark, but rather permit correct nesting.
Here are just a few examples of what can be done now:
${drjava.current.file}${drjava.current.file; dir="/Users/mgricken"}${drjava.current.file; dir="${user.home}"}— variables can be used again inside attribute values.${drjava.all.files}${drjava.all.files; sep=" "}${drjava.all.files; dir="${drjava.working.dir}"}${drjava.all.files; dir="${drjava.working.dir}"; sep=" "}${drjava.current.time.millis}${drjava.current.time.millis; fmt="full"}${drjava.current.time.millis; fmt="long"}${drjava.current.time.millis; fmt="medium"}${drjava.current.time.millis; fmt="short"}
When the user tries to set an attribute that isn’t valid for a property, an error is emitted. The syntax highlighting works fairly well.
Now I just have to add in all the properties I mentioned earlier…
