revusky

Revisiting Assertions, introducing the ENSURE keyword

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 …

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Announcement: CongoCC includes parsers for the latest Java and Python versions!

As the title says: as of this writing, the included grammars for Java and Python both support the latest versions of the respective languages, i.e. JDK 22 and Python 3.12. New Java Language Features Java language features that were not supported until quite recently were: Record patterns introduced as a stable feature in JDK 21. …

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All sorts of things you always wanted to know about tokenization but were afraid to ask (Part I)

Let’s consider the multiline comment in Java (and C/C++/C#, among others) which, you surely know, looks like this: /* * Comment text. */ This is an interesting construct. Paradoxically, it is extremely simple — I mean to describe in natural, human language (English or whatever) — but shockingly difficult to express in CongoCC. Or, that …

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The TERMINATING_STRING setting, a new (and quite minor!) feature

Some days ago, I added a new setting. If, at the top of your grammar, you write: TERMINATING_STRING=”some string”; this means that the input you’re parsing is guaranteed to end with that string. If the file ends with that string already, then it does nothing. Otherwise, it tacks that string to the end. In actual …

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NFA stands for “Nondeterministic finite automaton”. (Does that make you nervous?)

The main goal of the JavaCC 21 project, soon to be renamed as CongoCC, is to develop a very capable, practical, usable parser generator tool. However, there is another overarching goal — perhaps not so much a goal, as a philosophy. That can be summed up in a single word: Demystification You see, somehow or …

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