rustdoc: Add a pass to prune undocumented items

src/rustdoc/fold.rs

@@ -2,6 +2,7 @@ export fold;
 export fold_crate, fold_mod, fold_fn, fold_modlist, fold_fnlist;
 export default_seq_fold;
 export default_seq_fold_fn;
+export default_seq_fold_fnlist;
 
 tag fold<T> = t<T>;
 

src/rustdoc/prune_undoc_pass.rs

@@ -0,0 +1,67 @@
+export run;
+
+type ctxt = {
+    mutable have_docs: bool
+};
+
+fn run(
+    _srv: astsrv::seq_srv,
+    doc: doc::cratedoc
+) -> doc::cratedoc {
+    let ctxt = {
+        mutable have_docs: true
+    };
+    let fold = fold::fold({
+        fold_fn: fn~(
+            f: fold::fold<ctxt>,
+            d: doc::fndoc
+        ) -> doc::fndoc {
+            fold_fn(f, d)
+        },
+        fold_fnlist: fn~(
+            f: fold::fold<ctxt>,
+            l: doc::fnlist
+        ) -> doc::fnlist {
+            fold_fnlist(f, l)
+        }
+        with *fold::default_seq_fold(ctxt)
+    });
+    fold.fold_crate(fold, doc)
+}
+
+fn fold_fn(
+    fold: fold::fold<ctxt>,
+    doc: doc::fndoc
+) -> doc::fndoc {
+    fold.ctxt.have_docs =
+        doc.brief != none
+        || doc.desc != none
+        || doc.return != none;
+    ret doc;
+}
+
+fn fold_fnlist(
+    fold: fold::fold<ctxt>,
+    list: doc::fnlist
+) -> doc::fnlist {
+    doc::fnlist(vec::filter_map(*list) {|doc|
+        let doc = fold_fn(fold, doc);
+        if fold.ctxt.have_docs {
+            some(doc)
+        } else {
+            none
+        }
+    })
+}
+
+#[cfg(test)]
+mod tests {
+    #[test]
+    fn should_elide_undocumented_fns() {
+        let source = "fn a() { }";
+        let srv = astsrv::mk_seq_srv_from_str(source);
+        let doc = extract::from_srv(srv, "");
+        let doc = run(srv, doc);
+        assert vec::is_empty(*doc.topmod.fns);
+    }
+}

src/rustdoc/rustdoc.rc

@@ -15,5 +15,6 @@ mod gen;
 mod fold;
 mod attr_pass;
 mod tystr_pass;
+mod prune_undoc_pass;
 mod astsrv;
 mod util;

src/rustdoc/rustdoc.rs

@@ -77,6 +77,8 @@ fn run(source_file: str) {
     let doc = extract::from_srv(srv, default_name);
     let doc = run_passes(srv, doc, [
         attr_pass::run,
+        // FIXME: This pass should be optional
+        prune_undoc_pass::run,
         tystr_pass::run
     ]);
     gen::write_markdown(doc, std::io::stdout());