[wit-component] Extend the WIT printer for use in syntax highlighting #1956
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Extract the parametrized `Output` from `WitPrinter` in order to remove `Default` from the `Output` trait. `WitPrinter` is kept for backwards compatibility.
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Thanks for this! Are you planning on integrating this externally into an IDE or similar perhaps?
As an optional addition to this PR, it'd be pretty neat if this could get integrated into wasm-tools component wit in the same way that wasm-tools print will use terminal colors by default. No need to do that here though if you're not interested in doing so.
crates/wit-component/src/printing.rs
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| use wit_parser::*; | ||
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| // NB: keep in sync with `crates/wit-parser/src/ast/lex.rs` | ||
| const PRINT_F32_F64_DEFAULT: bool = true; | ||
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| /// A utility for printing WebAssembly interface definitions to a string. | ||
| pub struct WitPrinter { | ||
| output: Output, | ||
| ext: WitPrinterExt<OutputToString>, |
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FWIW it's ok to have breaking changes to this crate, so it might make more sense to repurpose the existing WitPrinter as WitPrinter<O> now?
| self.output.push_str(";"); | ||
| /// Print the specified package without its content. | ||
| /// Does not print the semicolon nor starts the indentation. | ||
| pub fn print_package_outer(&mut self, pkg: &Package) -> Result<()> { |
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How come some methods were made pub in this PR? It's totally ok to do so, but I just wanted to confirm this wasn't by accident and it was intentional
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It was intentional, answering here: #1956 (comment)
crates/wit-component/src/printing.rs
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| /// A newline is added. | ||
| fn newline(&mut self); | ||
| /// A keyword is added. Keywords are hardcoded strings from `[a-z]`, but can start with `@` | ||
| /// when printing a [Feature Gate](https://github.com/WebAssembly/component-model/blob/main/design/mvp/WIT.md#feature-gates) | ||
| fn keyword(&mut self, src: &str); | ||
| /// A type is added. | ||
| fn r#type(&mut self, src: &str, kind: TypeKind); | ||
| /// A parameter name of a function, record or a named return is added. | ||
| fn param(&mut self, src: &str); | ||
| /// A case belonging to a variant, enum or flags is added. | ||
| fn case(&mut self, src: &str); | ||
| /// Generic argument section starts. In WIT this represents the `<` character. | ||
| fn generic_args_start(&mut self); | ||
| /// Generic argument section ends. In WIT this represents the '>' character. | ||
| fn generic_args_end(&mut self); | ||
| /// Called when a single documentation line is added. | ||
| /// The `doc` parameter starts with `///` omitted, and can be an empty string. | ||
| fn doc(&mut self, doc: &str); | ||
| /// A semicolon is added. | ||
| fn semicolon(&mut self); |
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Do you think it might make sense to forward these methods to str by default? That way the implementation for OutputString could be a bit simpler perhaps
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I've extracted most of the functions into default trait methods, keeping only push_str and three others that are involved with indentation.
This reverts commit c23ad57.
…and `print_all`
…trait All methods that do not have to directly manipulate the state have now a default implementation.
Thanks for the quick review! I am building an HTML highlighter as part of a larger project - not just for displaying colors, but also for deeper integration, such as showing icons next to certain functions and filtering out parts of a WIT document. This is also why some higher-level functions are marked as pub in the PR. Here is how it looks now: |
crates/wit-component/src/printing.rs
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| impl<O: Output> WitPrinter<O> | ||
| where | ||
| String: From<O>, | ||
| { | ||
| /// Convenience wrapper around [`print_all`](WitPrinter::print_all) that prints the specified `pkg` which is located in `resolve` to a string. | ||
| /// | ||
| /// The `nested` list of packages are other packages to include at the end | ||
| /// of the output in `package ... { ... }` syntax. | ||
| pub fn print(self, resolve: &Resolve, pkg: PackageId, nested: &[PackageId]) -> Result<String> { | ||
| self.print_all(resolve, pkg, nested).map(String::from) | ||
| } | ||
| } |
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With self.output being a pub field could this be removed and could print_all below remain as print with &mut self? It should be ok to change its return value to Result<()> and then what to do with all the output is up to the caller with respect to self.output
As per PR request, merge `print` with `print_all`.
Introduce Output trait as a visitor for collecting syntax tokens.
This trait enables syntax highlighting and supports advanced use cases, such as filtering tokens by package, interface, or function.