1 files changed, 27 insertions, 2 deletions
diff --git a/src/main.rs b/src/main.rs
index c5bc049..8fa4efd 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -24,6 +24,7 @@ use std::env;
 use std::fs::metadata;
 use std::io::stdin;
 use std::path::PathBuf;
+use std::rc::Rc;
 
 use eyre::{bail, Result};
 
@@ -63,18 +64,42 @@ fn main() -> Result<()> {
     // TODO dump command-line macros into environment
     // TODO add SHELL macro
     let mut makefile = Makefile::new(&args);
+    let paths = Default::default();
     for filename in &args.makefile {
         if filename == &PathBuf::from("-") {
             let macros = makefile.macros.with_overlay();
-            let file = MakefileReader::read(&args, macros, stdin().lock(), "-")?.finish();
+            let file = MakefileReader::read(&args, macros, stdin().lock(), "-", Rc::clone(&paths))?
+                .finish();
             makefile.extend(file)?;
         } else {
             let macros = makefile.macros.with_overlay();
-            let file = MakefileReader::read_file(&args, macros, filename)?.finish();
+            let file =
+                MakefileReader::read_file(&args, macros, filename, Rc::clone(&paths))?.finish();
             makefile.extend(file)?;
         };
     }
 
+    let makefiles_outdated = paths
+        .borrow()
+        .iter()
+        .filter(|path| {
+            makefile
+                .get_target(path)
+                .map_or(false, |target| !target.borrow().is_up_to_date(&makefile))
+        })
+        .cloned()
+        .collect::<Vec<_>>();
+    for outdated in makefiles_outdated {
+        eprintln!("makefile {} out of date, rebuilding", outdated);
+        makefile.update_target(&outdated)?;
+        let macros = makefile.macros.with_overlay();
+        let file =
+            MakefileReader::read_file(&args, macros, &outdated, Default::default())?.finish();
+        // TODO forget the stale data
+        // TODO reread all the things, not just this one
+        makefile.extend(file)?;
+    }
+
     if args.print_everything {
         println!("{}", &makefile);
     } else {