implement lua-based templates

1 files changed, 44 insertions, 5 deletions

diff --git a/src/main.rs b/src/main.rs
index 2cd3a5d..e2fea85 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -18,7 +18,6 @@ use hyper::StatusCode;
 use hyper::{Body, Server};
 use origins::HttpOrigin;
 use percent_encoding::percent_decode_str;
-use pulldown_cmark::html;
 use pulldown_cmark::Options;
 use pulldown_cmark::Parser;
 use serde::Deserialize;
@@ -28,6 +27,7 @@ use sputnik::request::SputnikParts;
 use sputnik::response::SputnikBuilder;
 use std::convert::Infallible;
 use std::env;
+use std::fmt::Write;
 use std::path::Path;
 use std::sync::Arc;
 
@@ -516,14 +516,53 @@ enum RenderMode {
     Preview,
 }
 
-fn render_markdown(input: &str, page: &mut Page, _mode: RenderMode) {
-    let parser = Parser::new_ext(input, Options::all());
+fn render_markdown(text: &str, page: &mut Page, _mode: RenderMode, ctx: &Context) {
+    let md_options = Options::all();
+
     page.body.push_str("<div class=markdown-output>");
-    html::push_html(&mut page.body, parser);
+    #[cfg(feature = "lua")]
+    {
+        use lua::template::{parse_call_args, Sub};
+
+        let (text, state) = lua::template::preprocess(text);
+        let parser = Parser::new_ext(&text, md_options);
+        let mut out = String::new();
+        pulldown_cmark::html::push_html(&mut out, parser);
+
+        let out = state.postprocess(&out, |sub, out| match *sub {
+            Sub::Raw(raw) => out.write_str(&html_escape(raw)),
+            Sub::Pre { attrs, content } => {
+                write!(out, "<pre {attrs}>{}</pre>", html_escape(content))
+            }
+            Sub::StrayToken(_, text) => out.write_str(&html_escape(text)),
+            Sub::Call(text) => {
+                let (modfn, args) = parse_call_args(text);
+
+                // TODO: cache module source code to avoid unnecessary git reads for repeated templates
+                match lua::call(&modfn, args, ctx) {
+                    Ok(output) => out.write_str(&output),
+                    Err(err) => write!(
+                        out,
+                        "<span class=error>{}: {}</span>",
+                        html_escape(modfn.module_name), // TODO: link module
+                        &html_escape(err.to_string()),
+                    ),
+                }
+            }
+        });
+        page.body.push_str(&out);
+    }
+    #[cfg(not(feature = "lua"))]
+    {
+        let parser = Parser::new_ext(text, md_options);
+        let mut out = String::new();
+        pulldown_cmark::html::push_html(&mut out, parser);
+        page.body.push_str(&out);
+    }
     page.body.push_str("</div>");
 }
 
-fn get_renderer(path: &Utf8Path) -> Option<fn(&str, &mut Page, RenderMode)> {
+fn get_renderer(path: &Utf8Path) -> Option<fn(&str, &mut Page, RenderMode, ctx: &Context)> {
     match path.extension() {
         Some("md") => Some(render_markdown),
         _ => None,