A parser for WGSL files, written directly from the specification with lalrpop.

Parsing a source file

let source = "@fragment fn frag_main() -> @location(0) vec4f { return vec4(1); }";
let parsed = wgsl_parse::Parser::parse_str(source).unwrap();

let compare = TranslationUnit {
    global_directives: vec![],
    global_declarations: vec![GlobalDeclaration::Function(Function {
        attributes: vec![Attribute {
            name: "fragment".to_string(),
            arguments: None
        }],
        name: "frag_main".to_string(),
        parameters: vec![],
        return_attributes: vec![Attribute {
            name: "location".to_string(),
            arguments: Some(vec![Expression::Literal(LiteralExpression::AbstractInt(0))])
        }],
        return_type: Some(TypeExpression {
            name: "vec4f".to_string(),
            template_args: None
        }),
        body: CompoundStatement {
            attributes: vec![],
            statements: vec![Statement::Return(Some(Expression::FunctionCall(
                FunctionCallExpression {
                    name: "vec4".to_string(),
                    template_args: None,
                    arguments: vec![Expression::Literal(LiteralExpression::AbstractInt(1))]
                }
            )))]
        }
    })]
};

assert_eq!(parsed, compare);

Syntax tree

See syntax tree.

Modifying the syntax tree:

    let source = "const hello = 0u;";
    let mut module = wgsl_parse::Parser::parse_str(source).unwrap();

    // modify the module as needed...
    let decl = &mut module
        .global_declarations
        .iter_mut()
        .find_map(|decl| match decl {
            wgsl_parse::syntax::GlobalDeclaration::Declaration(decl) => Some(decl),
            _ => None,
        })
        .unwrap();
    decl.name = "world".to_string();

    assert_eq!(format!("{module}").trim(), "const world = 0u;");

Stringification

The syntax tree elements implement Display. The display is always pretty-printed.

TODO: implement :# for pretty vs. inline formatting.

let source = "@fragment fn frag_main() -> @location(0) vec4f { return vec4(1); }";
let mut module = wgsl_parse::Parser::parse_str(source).unwrap();

// modify the module as needed...

println!("{module}");