Posts relating to the JavaCC roadmap for future development
Assertions, implemented in late 2021, are certainly an important feature in CongoCC — actually pretty much essential when writing grammars for very gnarly languages. However, as currently implemented, they are admittedly a somewhat strange hybrid construct. The main reason for this is that ASSERT has completely different semantics depending on whether you hit the assertion …
Revisiting Assertions, introducing the ENSURE keyword Read More »
The following essay outlines the main evolution in the API generated by CongoCC from its origins in the Dark Ages up until now. The Journey of a Thousand Leagues Begins with a Single Step Let’s say you go on an excursion to a national park and there is a well known hiking trail that goes …
Now that the ability to generate fault-tolerant parsers is coming along so well, I have been thinking about what to do with the Java grammar included in CongoCC. I decided that the best thing to do was to do the incremental work to make it maximally correct. Ideally, it will serve as a reference implementation …
Moving Towards a Maximally Correct Reference Java Grammar Read More »
When I say "fully supported", I mean all the new features that are categorized as "stable". In fact, the only new language feature that has been promoted to stable in JDK 14 is the new syntax for the Switch statement. This also allows a Switch statement to be used as an expression. In fact, the …
Revisiting LOOKAHEAD Redux Not so long ago, I had a sort of eureka moment when I realized that the legacy LOOKAHEAD construct was fundamentally half-baked or broken. Not only that, but I started narrowing in on how to definitely address the issue! Well, let’s get concrete. Suppose we have a production that looks kind of like this: FooBar : …
New Feature: The =>|| delimiter stands for “scan up to here” Read More »
If you liked LOOKAHEAD, then you’ll love LOOKBEHIND! Actually, I have not added LOOKBEHIND as a new keyword in JavaCC. It is just an informal way of referring to a new feature that I recently added. I implemented this because I realized that there was a very common thing people want to do in a JavaCC grammar …
A few months ago, I started re-examining some of the legacy JavaCC syntax. I realized the pure absurdity of having to write: LOOKAHEAD(Foo() Bar() Baz()) Foo() Bar() Baz() In short order, I allowed people to write the above as: LOOKAHEAD Foo() Bar() Baz() But this started me thinking…. I reasoned that there were doubtless plenty …
Some years back, I was traveling with a couple of Spanish friends, and this was late 2012. We were in Kunming, China and came across a poster that advertised some live music. I was fumbling around for a pen and a bit of paper to jot down the information. I thought to ask my traveling …
It’s Official! The Gigabyte is the new Megabyte! Hurrah! Read More »
A bit over a month ago, I wrote about my intention of tearing out support for “JAVACODE” productions. A JAVACODE production is really just a Java method that is like a pretend grammatical production. I could find very few JavaCC grammars in the wild that used this. I asked whether anybody would miss them and …
One of the very basic goals of this iteration of work on the JavaCC codebase, JavaCC 21, is to turn this into a capable tool for generating fault-tolerant parsers. Traditionally, not just JavaCC, but tools in this space generally, consider that it is their job to parse, i.e. to break down input into its various pieces …