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 …
The poster child for this feature would be something like the C-style multiline comment, i.e. /** * comment */ It is actually surprisingly difficult to specify this in legacy JavaCC (or JavaCC21/Congo up until very recently). One way is to break it into multiple regexp patterns using the MORE feature. Or, alternatively, there is actually …
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 …
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 …
The TERMINATING_STRING setting, a new (and quite minor!) feature Read More »
A few weeks ago, in a previous post I wrote: The problem, at the time of this writing, is that neither JavaCC21 nor legacy JavaCC have any concept of characters outside of plane 0, which are the ones that require 4 bytes of internal storage. Or another way of putting this is that the assumption …
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 …