feat: setup for tree-sitter syntax highlighting

src/main.rs

@@ -25,6 +25,7 @@ use tracing_subscriber::FmtSubscriber;
 
 use crate::typst::TypstContext;
 
+mod syntax;
 mod typst;
 
 #[derive(Clone)]
@@ -59,6 +60,10 @@ struct AppConfig {
     #[arg(short = 'd', long, value_name = "DIR", default_value = "/tmp/karnaugh")]
     packages_root: PathBuf,
 
+    /// The directory where the syntax files are stored.
+    #[arg(short = 'g', long, value_name = "DIR", default_value = None)]
+    syntax_root: Option<PathBuf>,
+
     /// The log level to use
     #[arg(short = 'l', long, value_name = "LEVEL", default_value_t = Level::INFO)]
     log_level: Level,
@@ -94,6 +99,8 @@ async fn main() {
         .with_max_level(state.config.log_level)
         .init();
 
+    syntax::init(&state.config);
+
     // TODO: Replace with config option
     let mut favicon = state.config.get_full_assets_path();
     favicon.push(PathBuf::from("favicon.svg"));

src/syntax.rs

@@ -0,0 +1,48 @@
+use std::{path::PathBuf, sync::OnceLock};
+
+use tracing::{info, warn};
+use typst::foundations::{Func, NativeFunc, func};
+
+use crate::AppConfig;
+
+static REGISTRY: OnceLock<LanguageRegistry> = OnceLock::new();
+
+struct LanguageRegistry {}
+
+impl LanguageRegistry {
+    fn new(syntax_root: &PathBuf) -> Self {
+        Self {}
+    }
+}
+
+pub fn init(config: &AppConfig) {
+    match &config.syntax_root {
+        Some(syntax_root) => {
+            info!("Loading syntax files");
+            REGISTRY.get_or_init(|| LanguageRegistry::new(syntax_root));
+        }
+        None => {
+            warn!(
+                "No syntax root has been configured, improved tree-sitter highlighting will not be possible."
+            )
+        }
+    }
+}
+
+pub fn highlight_func() -> Func {
+    highlight::func()
+}
+
+#[func]
+fn highlight(
+    text: String,
+    #[named]
+    #[default(false)]
+    block: bool,
+    #[named]
+    #[default(None)]
+    lang: Option<String>,
+) -> String {
+    let rev = text.chars().rev();
+    rev.collect()
+}

src/typst.rs

@@ -5,7 +5,7 @@ use tracing::info;
 use typst::{
     Library, LibraryExt, World,
     diag::{FileError, FileResult, PackageError, PackageResult, SourceDiagnostic},
-    foundations::{Bytes, Datetime, Duration},
+    foundations::{Bytes, Datetime, Dict, Duration, Value},
     syntax::{FileId, RootedPath, Source, VirtualPath, VirtualRoot, package::PackageSpec},
     text::{Font, FontBook},
     utils::LazyHash,
@@ -23,7 +23,15 @@ pub struct TypstContext {
 
 impl TypstContext {
     pub fn new(config: AppConfig) -> Self {
+        let mut inputs = Dict::new();
+        if config.syntax_root.is_some() {
+            inputs.insert(
+                "highlight".into(),
+                Value::Func(crate::syntax::highlight_func()),
+            );
+        }
         let library = Library::builder()
+            .with_inputs(inputs)
             .with_features([typst::Feature::Html].into_iter().collect())
             .build();
         let library = LazyHash::new(library);