AntlrVSIX v2.0

Due to my work on Piggy and Campy, I’m extending my Antlr4 extension for Visual Studio in a number of ways. The plug-in hasn’t been updated for two years, and there are no extensions for Antlr that work with Visual Studio 2019, so it is due for an update. In fact, there isn’t a single extension for Antlr for Visual Studio 2019, and Antlr.org removed Visual Studio from the list of developer tools for Antlr.

Changes

Targeting Visual Studio 2019 and 2017

I’m not sure where I read it, but “good practice” says I should only support the current version and one version previous.

Improved Tagging

I’ve added new tags for channels and modes, and the whole classification and tagging routines now check if the source has changed before reparsing, which improves performance.

A menu for AntlrVSIX in Extensions

In Visual Studio 2019, the menus for extensions are where you should look–under “Extensions”. Previously, I have to admit that it was hard to figure out the UI for AntlrVSIX, hidden under various menus, or available through a right-click context menu. That’s basically bad UI design.

Although the right-click context menu for AntlrVSIX is still available, it mirrors exactly what you see in the main menu under “Extensions -> AntlrVSIX”.

Navigation to next and previous rules in a grammar file

I’m a big fan of the old-style Emacs and even older Vi! Back then, UI was keyboard-oriented. It was much more efficient instead of moving around this stupid mouse, pointing to something I can hardly see on the screen.

I’ve added a few new ways to navigate around a grammar file with some shortcuts. “Next rule” jumps to the next rule in a grammar; “Previous rule” jumps to the previous rule in the grammar; “Go to Visitor” navigates to a visitor method for a tree node corresponding to a non-terminal.

Generation of Visitors and Listeners

Go to visitor/listener jumps to C# code for grammar symbol. If the method doesn’t exist, then the Visitor or Listener classes and methods are generated.

Options for the extension

An options dialog box for extension-specific parameters is now included. It is needed for things like where to find the “corpus” of examples of formatted grammars that Codebuff will use to format your grammar.

Performance

While AntlrVSIX is the only extension for VS 2019, it’s rarely used compared to several other older–and in my opinion, less useful extensions. AntlrVSIX has had only one review, which says the performance sucks. (Thanks, dude for not saying *what* specifically are you trying to do that is slow. I’d never have you on my QA team–not helpful descriptions).

Performance has taken a more front seat with this release. Before parsing, I check whether the code buffer has changed.

Significant cleanup and bug fix of the source code

I spent a lot of the time cleaning up the source code. At the time when I first wrote the extension, I had no clue how to modify which feature in the UI because the documentation for Visual Studio extensions is absolutely terrible. I now have a better command of what is going on and fixed a lot of the code.

Migration from packages.config to PackageReference builds

It’s absolutely appalling that the examples for extensions Microsoft provides is out of date and are so poor. Many still use the “packages.config” file to list the NuGet dependencies of a C# project. I’ve updated AntrlVSIX to use the latest format, which required the tool to be migrated to Net 4.7.2.

Integrating builds with Antlr4BuildTasks

You can’t really have an extension for a language like Antlr if you don’t include some way of actually *building* the project that uses the language. After first writing AntlrVSIX, I then modified Antlr4cs, a wrapper for a C# version of the Antlr tool, to just be a wrapper the standard Antlr4 Java tool. So, it now generates the parsers/lexers in the IDE.

In addition, the Antlr4BuildTasks had a bug where one couldn’t change the build mode of the .g4 file to none. This is required for multi-file grammars that use the “import” statement in Antlr.

Fixing Intellisense

I fixed the Intellisense for the extension. The tooltip now works when hovering over a single-character grammar symbol. Command completion now offers a list of grammar symbols in the grammar.

*****

The work on the extension has been going on for two weeks and should be finished in the next week.

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