chore: add custom_renderer example

examples/custom_renderer.rs

@@ -0,0 +1,80 @@
+use std::{borrow::Cow, collections::HashMap, error::Error};
+
+use syntastica::{renderer::Renderer, Processor};
+use syntastica_core::style::Style;
+use syntastica_parsers_git::{Lang, LanguageSetImpl};
+
+fn main() -> Result<(), Box<dyn Error>> {
+    let examples: HashMap<String, String> =
+        toml::from_str(include_str!("./example_programs.toml"))?;
+
+    let language_set = LanguageSetImpl::new();
+    language_set.preload(&[Lang::Rust, Lang::Regex, Lang::C])?;
+    let mut processor = Processor::new(&language_set);
+    let theme = syntastica_themes::one::light();
+
+    println!(
+        "{}",
+        syntastica::render(
+            &processor.process(&examples["rust"], Lang::Rust)?,
+            &mut TypstRenderer,
+            &theme
+        ),
+    );
+    println!(
+        "{}",
+        syntastica::render(
+            &processor.process(&examples["c"], Lang::C)?,
+            &mut TypstRenderer,
+            &theme
+        ),
+    );
+
+    Ok(())
+}
+
+/// A renderer for syntastica which outputs code for use in [Typst](https://typst.app/) documents.
+pub struct TypstRenderer;
+// for information on the trait methods, see the trait docs
+impl Renderer for TypstRenderer {
+    fn head(&mut self) -> Cow<'static, str> {
+        "#{".into()
+    }
+
+    fn tail(&mut self) -> Cow<'static, str> {
+        "}".into()
+    }
+
+    fn newline(&mut self) -> Cow<'static, str> {
+        r"linebreak();".into()
+    }
+
+    fn unstyled<'a>(&mut self, text: &'a str) -> Cow<'a, str> {
+        format!("raw({text:?});").into()
+    }
+
+    fn styled<'a>(&mut self, text: &'a str, style: Style) -> Cow<'a, str> {
+        let (r, g, b) = style.color().into_components();
+        let mut options = format!("fill:rgb({r},{g},{b}),");
+        let mut front = String::new();
+        let mut paren_count = 0;
+        if style.underline() {
+            front += "underline(";
+            paren_count += 1;
+        }
+        if style.strikethrough() {
+            front += "strike(";
+            paren_count += 1;
+        }
+        if style.italic() {
+            options += "style:\"italic\",";
+        }
+        if style.bold() {
+            options += "weight:\"bold\",";
+        }
+
+        // trim the trailing `;` that `unstyled()` adds after raw text
+        let text = &text[..text.len().saturating_sub(1)];
+        format!("{front}text({options}{text}){};", ")".repeat(paren_count)).into()
+    }
+}