From 2d5e084fed84813d7300d46263ca9b5e50b38916 Mon Sep 17 00:00:00 2001
From: Michael Williamson <mike@zwobble.org>
Date: Sat, 21 Oct 2023 11:20:50 +0100
Subject: Order namespaces

---
 .../java/org/shedlang/compiler/ShedCompiler.java   | 41 +++++++++++++++++++---
 1 file changed, 36 insertions(+), 5 deletions(-)

(limited to 'src/main/java')

diff --git a/src/main/java/org/shedlang/compiler/ShedCompiler.java b/src/main/java/org/shedlang/compiler/ShedCompiler.java
index 6d917f1d..02ec0e28 100644
--- a/src/main/java/org/shedlang/compiler/ShedCompiler.java
+++ b/src/main/java/org/shedlang/compiler/ShedCompiler.java
@@ -21,10 +21,8 @@ import java.nio.file.Files;
 import java.nio.file.Path;
 import java.nio.file.SimpleFileVisitor;
 import java.nio.file.attribute.BasicFileAttributes;
-import java.util.ArrayList;
-import java.util.Comparator;
-import java.util.List;
-import java.util.Map;
+import java.util.*;
+import java.util.stream.Collectors;
 import java.util.stream.StreamSupport;
 
 import static org.shedlang.compiler.parser.Tokeniser.tokenise;
@@ -55,7 +53,7 @@ public class ShedCompiler {
                 Map.entry(ShedBuiltins.PRINT_NAME, ShedBuiltins.PRINT_TYPE)
             ));
 
-        for (var untypedNamespaceNode : untypedNamespaceNodes) {
+        for (var untypedNamespaceNode : orderSourceFiles(untypedNamespaceNodes)) {
             var typeCheckNamespaceResult = TypeChecker.typeCheckNamespace(untypedNamespaceNode, typeCheckerContext);
             typeCheckerContext = typeCheckNamespaceResult.context();
 
@@ -118,4 +116,37 @@ public class ShedCompiler {
 
         return untypedNamespaceNodes;
     }
+
+    private List<UntypedNamespaceNode> orderSourceFiles(
+        List<UntypedNamespaceNode> untypedNamespaceNodes
+    ) {
+        var nodesByName = untypedNamespaceNodes.stream()
+            .collect(Collectors.toMap(x -> x.namespaceName(), x -> x));
+
+        var seen = new HashSet<NamespaceName>();
+        var ordered = new ArrayList<UntypedNamespaceNode>();
+
+        // TODO: test this!
+        // TODO: handle infinite loops
+        // TODO: handle missing namespaces
+
+        var adder = new Object() {
+            private void add(NamespaceName name) {
+                if (!seen.contains(name)) {
+                    var untypedNamespaceNode = nodesByName.get(name);
+                    for (var import_ : untypedNamespaceNode.imports()) {
+                        add(import_.namespaceName());
+                    }
+                    seen.add(name);
+                    ordered.add(untypedNamespaceNode);
+                }
+            }
+        };
+
+        for (var untypedNamespaceNode : untypedNamespaceNodes) {
+            adder.add(untypedNamespaceNode.namespaceName());
+        }
+
+        return ordered;
+    }
 }
-- 
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