Tips and Tricks

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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Announcement: JavaCC 21 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 language, JDK 17 and Python 3.10 respectively. Contextual Keywords It turns out that, from a language support perspective, the only new stable feature in JDK 17 is the concept of sealed classes. This …

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Context-Sensitive Tokenization, Next Installment, Activating and De-activating Tokens

Sometimes, when you complete a major code cleanup, features that were previously pie in the sky become low-hanging fruit to pluck. The new feature that I describe here, the ability to activate and deactivate tokens is such a case. It resulted from my rewriting of the lexical code generation that I describe here. In an …

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Context-Sensitive Tokenizing, Part Deux: Lexical States

(To get some prerequisite understanding of this topic, it might be a good idea to read this earlier blog post on context-sensitive tokenization from three months ago.) The Lay of the Land There are two quite useful ideas that have been in JavaCC from the very beginning: lookahead (particularly syntactic lookahead) lexical states Syntactic lookahead …

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Tastes just like home-made! (Some more tree building enhancements)

Before getting into what the minor enhancements to tree building are, I guess I should write a quick synopsis of the current state of affairs. When you have TREE_BUILDING_ENABLED set to true (this is the default in JavaCC21) the tree building machinery will build a Node if the production results in the creation of more …

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