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 …
NFA stands for “Nondeterministic finite automaton”. (Does that make you nervous?) Read More »
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 »
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 …
Tastes just like home-made! (Some more tree building enhancements) Read More »
I recently introduced a couple of "pseudo-annotations" (I’ll explain the pseudo part later) that can be used in code injections to express things in a much more succint manner. Here is an example: INJECT Foo : { @property String name; … } and the code generated in Foo.java corresponding to that line will be: private …
(N.B. Note added 13 June 2021: This article is useful in terms of understanding how to add token hooks to code. However, in terms of solving the specific problem outlined, the article is obsolete. See here for the updated solution.) Since I picked up my work on the JavaCC codebase at the end of 2019, …
“You can’t get there from here!” — The Problem of Context-Sensitive Tokenization Read More »
In the beginning there was… CommonTokenAction Legacy JavaCC had (and still has) a means of applying whatever adjustments (a.k.a. kludges) to a Token just before it is handed off to the parser machinery. You could define a method called CommonTokenAction in your Lexer TokenManager class and this method is invoked when you get another Token …
Programmatically generating code is a little world in itself, with its own little quirks and tricks. Consider the generation of the C-style switch-case with fall-through. You have your code generation that generates all your cases, and each case ends with a break. There is a problem, which is that the moment any of your case …