tree-sitter-wgsl-bevy

This is a extension of tree-sitter-wgsl to support the Bevy Naga OIL preprocessor.

Objective

The objective was to update the existing project which seems unmaintened. As I needed quite quickly a parser to work with wgsl-bevy-ts-mode which is a major editing mode for emacs.

I expect the following to print '0':

find ~/prog/bevy/ -name "*.wgsl" -exec tree-sitter parse {} \; | grep ERROR | wc -l

meaning: it parse 100% of bevy's wgsl code without any parse error.

Known issues

Adding a string in a comment:

const a: f32 = 0.0;

// this is a comment with a string: "hellow"
fn fun() {

}

Will sadly makes syntax ERROR unrecoverable when the parser fail, and the whole buffer will be interpreted as a list of string. Which will make most syntax highlighter stop working until the syntax is fixed.

It's coming from the fact, that everything is a "string_content", whenever the scanner detect a double quote.

"string_content" is mostly used for "path import":

#import "path/to/a/shader/file.wgsl"::STUFF_TO_IMPORT

Stuff to improve

Contribution welcome.

• I don't think it's fixable, but the grammar suffer from the same desease a the C one => it's impossible to correctly parse #ifdef without an actual pre-pass.
• Some improvements are actually WGSL standard spec improvement and not Bevy only. But I didn't want to update the main WGSL grammar, so I overwrite some things which could be ported back into the main WGSL grammar this grammar is based upon.
• I reused 'import_path' quite a lots instead of creating a "identifier::identifier::*", which make it difficult for syntax highlight and function call.
• import_path + import_list, is junky but functionnal. Might need to make a better tree here.
• Function call and type Declaration is the same node, which make formatting kindda ugly.