Sort balance directives ahead of others for the same day (#31)

Fixes #30

Author: tesujimath

Cargo.lock

@@ -1,6 +1,6 @@
 [package]
 name = "beancount-parser-lima"
-version = "0.11.0"
+version = "0.11.1"
 edition = "2021"
 license = "MIT OR Apache-2.0"
 description = "A zero-copy parser for Beancount"

Cargo.toml

@@ -551,9 +551,17 @@ impl<'s> BeancountParser<'s> {
         let error_paths = self.sources.error_path_iter().collect::<HashMap<_, _>>();
         let mut p = PragmaProcessor::new(self.root_path(), parsed_sources, error_paths, options);
 
+        // directives are stable-sorted by date, where balance directives sort ahead of the other directives for that day
+        // as per https://beancount.github.io/docs/beancount_design_doc.html#stream-invariants
         let directives = p
             .by_ref()
-            .sort(|d| *d.item().date().item())
+            .sort(|d| {
+                (
+                    *d.item().date().item(),
+                    // secondary sort of Balance ahead of others
+                    !matches!(d.variant(), DirectiveVariant::Balance(_)),
+                )
+            })
             .collect::<Vec<_>>();
         let (options, plugins, mut pragma_errors) = p.result();
         errors.append(&mut pragma_errors);

src/lib.rs

@@ -1,16 +1,15 @@
-# ANOMALY: Lima returns directives in date order
 directives {
   date { year: 2000 month: 1 day: 1 }
   open { account: "Assets:Before" }
 }
-directives {
-  date { year: 2010 month: 1 day: 1 }
-  close { account: "Assets:Before" }
-}
 directives {
   date { year: 2010 month: 1 day: 1 }
   balance {
     account: "Assets:Before"
     amount { number { exact: "100" } currency: "USD" }
   }
 }
+directives {
+  date { year: 2010 month: 1 day: 1 }
+  close { account: "Assets:Before" }
+}