Added a syntax highlighting example

mitsuhiko · Jun 17, 2024 · 9495cda · 9495cda
1 parent ab41e94
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diff --git a/Cargo.lock b/Cargo.lock
diff --git a/examples/syntax-highlighting/Cargo.toml b/examples/syntax-highlighting/Cargo.toml
@@ -0,0 +1,11 @@
+[package]
+name = "syntax-highlighting"
+version = "0.1.0"
+edition = "2018"
+publish = false
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[dependencies]
+minijinja = { path = "../../minijinja" }
+syntect = { version = "5.2.0", default-features = false, features = ["default-fancy", "default-syntaxes"] }
diff --git a/examples/syntax-highlighting/README.md b/examples/syntax-highlighting/README.md
@@ -0,0 +1,7 @@
+# syntax-highlighting
+
+An example that shows how to register a function for syntax highlighting wiht syntect.
+
+```console
+$ cargo run
+```
diff --git a/examples/syntax-highlighting/src/example.html b/examples/syntax-highlighting/src/example.html
@@ -0,0 +1,9 @@
+<!doctype html>
+<title>Syntax Highlight Example</title>
+<h1>Syntax Highlight Example</h1>
+{% do highlight.set_theme("base16-ocean.light") %}
+{% call highlight('rust') %}
+fn main() {
+    println!("Hello World!");
+}
+{% endcall %}
diff --git a/examples/syntax-highlighting/src/main.rs b/examples/syntax-highlighting/src/main.rs
@@ -0,0 +1,92 @@
+use std::sync::{Arc, Mutex};
+
+use minijinja::value::{from_args, Kwargs, Object};
+use minijinja::{args, Environment, Error, ErrorKind, State, Value};
+use syntect::highlighting::ThemeSet;
+use syntect::html::highlighted_html_for_string;
+use syntect::parsing::SyntaxSet;
+
+#[derive(Debug)]
+struct Highlighter {
+    ss: SyntaxSet,
+    ts: ThemeSet,
+    theme: Arc<Mutex<String>>,
+}
+
+impl Highlighter {
+    pub fn new() -> Highlighter {
+        let ss = SyntaxSet::load_defaults_newlines();
+        let ts = ThemeSet::load_defaults();
+        Highlighter {
+            ss,
+            ts,
+            theme: Mutex::new("InspiredGitHub".to_string()).into(),
+        }
+    }
+}
+
+impl Object for Highlighter {
+    fn call(self: &Arc<Self>, state: &State<'_, '_>, args: &[Value]) -> Result<Value, Error> {
+        let (lang, kwargs): (&str, Kwargs) = from_args(args)?;
+        let caller: Value = kwargs.get("caller")?;
+        let content = caller.call(state, args!())?;
+        let mut content_str = content.as_str().ok_or_else(|| {
+            Error::new(
+                ErrorKind::InvalidOperation,
+                "call block did not return a string",
+            )
+        })?;
+        if let Some(rest) = content_str.strip_prefix('\n') {
+            content_str = rest;
+        }
+        let syntax = self.ss.find_syntax_by_token(lang).ok_or_else(|| {
+            Error::new(
+                ErrorKind::InvalidOperation,
+                format!("unknown language {}", lang),
+            )
+        })?;
+        kwargs.assert_all_used()?;
+        let theme = self.theme.lock().unwrap();
+        let rv = highlighted_html_for_string(
+            content_str,
+            &self.ss,
+            syntax,
+            &self.ts.themes[&theme as &str],
+        )
+        .map_err(|err| {
+            Error::new(ErrorKind::InvalidOperation, "failed to syntax highlight").with_source(err)
+        })?;
+        Ok(Value::from_safe_string(rv))
+    }
+
+    fn call_method(
+        self: &Arc<Self>,
+        _state: &State<'_, '_>,
+        method: &str,
+        args: &[Value],
+    ) -> Result<Value, Error> {
+        match method {
+            "set_theme" => {
+                let (name,): (String,) = from_args(args)?;
+                if !self.ts.themes.contains_key(&name) {
+                    return Err(Error::new(
+                        ErrorKind::InvalidOperation,
+                        format!("unknown theme {}", name),
+                    ));
+                }
+                *self.theme.lock().unwrap() = name;
+                Ok(Value::UNDEFINED)
+            }
+            _ => Err(Error::from(ErrorKind::UnknownMethod)),
+        }
+    }
+}
+
+fn main() {
+    let mut env = Environment::new();
+    env.add_global("highlight", Value::from_object(Highlighter::new()));
+    env.add_template("example.html", include_str!("example.html"))
+        .unwrap();
+    let template = env.get_template("example.html").unwrap();
+    println!("{}", template.render(()).unwrap());
+}
diff --git a/examples/syntax-highlighting/test.html b/examples/syntax-highlighting/test.html
@@ -0,0 +1,10 @@
+<!doctype html>
+<title>Syntax Highlight Example</title>
+<h1>Syntax Highlight Example</h1>
+
+<pre style="background-color:#eff1f5;">
+<span style="color:#b48ead;">fn </span><span style="color:#8fa1b3;">main</span><span style="color:#4f5b66;">() {
+</span><span style="color:#4f5b66;">    println!(&quot;</span><span style="color:#a3be8c;">Hello World!</span><span style="color:#4f5b66;">&quot;);
+</span><span style="color:#4f5b66;">}
+</span></pre>
+