Extract and test namespace linearisation

3 files changed, 62 insertions, 37 deletions

diff --git a/src/main/java/org/shedlang/compiler/ShedCompiler.java b/src/main/java/org/shedlang/compiler/ShedCompiler.java
index 8c2407d6..177f6fd5 100644
--- a/src/main/java/org/shedlang/compiler/ShedCompiler.java
+++ b/src/main/java/org/shedlang/compiler/ShedCompiler.java
@@ -6,9 +6,9 @@ import org.shedlang.compiler.backends.paths.TargetDir;
 import org.shedlang.compiler.config.ConfigChecker;
 import org.shedlang.compiler.config.ProjectConfig;
 import org.shedlang.compiler.parser.Parser;
-import org.shedlang.compiler.sources.Sources;
 import org.shedlang.compiler.shid.ShidCodeGen;
 import org.shedlang.compiler.shid.ShidNamespace;
+import org.shedlang.compiler.sources.Sources;
 import org.shedlang.compiler.typechecker.TypeChecker;
 import org.shedlang.compiler.typechecker.TypeCheckerContext;
 import org.shedlang.compiler.types.*;
@@ -21,11 +21,14 @@ import java.nio.file.Files;
 import java.nio.file.Path;
 import java.nio.file.SimpleFileVisitor;
 import java.nio.file.attribute.BasicFileAttributes;
-import java.util.*;
-import java.util.stream.Collectors;
+import java.util.ArrayList;
+import java.util.Comparator;
+import java.util.List;
+import java.util.Map;
 import java.util.stream.StreamSupport;
 
 import static org.shedlang.compiler.parser.Tokeniser.tokenise;
+import static org.shedlang.compiler.typechecker.NamespaceDependencyLineariser.orderNamespaces;
 
 public class ShedCompiler {
     public void compile(Path projectRoot, Backend backend) throws IOException, InterruptedException {
@@ -56,7 +59,7 @@ public class ShedCompiler {
                 Map.entry(ShedBuiltins.PRINT_NAME, ShedBuiltins.PRINT_TYPE)
             ));
 
-        for (var untypedNamespaceNode : orderSourceFiles(untypedNamespaceNodes)) {
+        for (var untypedNamespaceNode : orderNamespaces(untypedNamespaceNodes)) {
             var typeCheckNamespaceResult = TypeChecker.typeCheckNamespace(untypedNamespaceNode, typeCheckerContext);
             typeCheckerContext = typeCheckNamespaceResult.context();
 
@@ -128,37 +131,4 @@ 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;
-    }
 }
diff --git a/src/main/java/org/shedlang/compiler/ast/untyped/UntypedNamespaceNode.java b/src/main/java/org/shedlang/compiler/ast/untyped/UntypedNamespaceNode.java
index 164feb6f..20126d59 100644
--- a/src/main/java/org/shedlang/compiler/ast/untyped/UntypedNamespaceNode.java
+++ b/src/main/java/org/shedlang/compiler/ast/untyped/UntypedNamespaceNode.java
@@ -27,6 +27,14 @@ public record UntypedNamespaceNode(
             return new UntypedNamespaceNode(namespaceName, imports, body, Sources.NULL);
         }
 
+        public Builder withNamespaceName(NamespaceName namespaceName) {
+            return new Builder(
+                namespaceName,
+                this.imports,
+                this.body
+            );
+        }
+
         public Builder addImport(UntypedImportNode import_) {
             return new Builder(namespaceName, imports.plus(import_), body);
         }
diff --git a/src/main/java/org/shedlang/compiler/typechecker/NamespaceDependencyLineariser.java b/src/main/java/org/shedlang/compiler/typechecker/NamespaceDependencyLineariser.java
new file mode 100644
index 00000000..bedb0070
--- /dev/null
+++ b/src/main/java/org/shedlang/compiler/typechecker/NamespaceDependencyLineariser.java
@@ -0,0 +1,47 @@
+package org.shedlang.compiler.typechecker;
+
+import org.shedlang.compiler.ast.untyped.UntypedNamespaceNode;
+import org.shedlang.compiler.types.NamespaceName;
+
+import java.util.ArrayList;
+import java.util.HashSet;
+import java.util.List;
+import java.util.stream.Collectors;
+
+public class NamespaceDependencyLineariser {
+    private NamespaceDependencyLineariser() {
+    }
+
+    public static List<UntypedNamespaceNode> orderNamespaces(
+        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;
+    }
+}