Index: src/Concurrency/Corun.cpp
===================================================================
--- src/Concurrency/Corun.cpp	(revision eb779d5ca94c2de1db899969438189f4b2c05b4b)
+++ src/Concurrency/Corun.cpp	(revision eb779d5ca94c2de1db899969438189f4b2c05b4b)
@@ -0,0 +1,96 @@
+//
+// Cforall Version 1.0.0 Copyright (C) 2015 University of Waterloo
+//
+// The contents of this file are covered under the licence agreement in the
+// file "LICENCE" distributed with Cforall.
+//
+// Corun.cpp -- generate code needed by the actor system
+//
+// Author           : Colby Parsons
+// Created On       : Monday October 9 15:16:42 2023
+// Last Modified By : Colby Parsons
+// Last Modified On : Monday October 9 15:16:42 2023
+// Update Count     : 0
+//
+
+#include "AST/Decl.hpp"
+#include "AST/Expr.hpp"
+#include "AST/Pass.hpp"
+#include "AST/Stmt.hpp"
+#include "AST/TranslationUnit.hpp"
+#include "Common/UniqueName.h"
+using namespace ast;
+using namespace std;
+
+namespace Concurrency {
+
+struct CorunKeyword : public WithDeclsToAdd<>, public WithStmtsToAdd<> {
+    UniqueName CorunFnNamer = "__CFA_corun_lambda_"s;
+    UniqueName RunnerBlockNamer = "__CFA_corun_block_"s;
+
+    const StructDecl * runnerBlockDecl = nullptr;
+
+    // Finds select_node decl
+    void previsit( const StructDecl * decl ) {
+        if ( !decl->body ) {
+            return;
+        } else if ( "runner_block" == decl->name ) {
+            assert( !runnerBlockDecl );
+            runnerBlockDecl = decl;
+        }
+    }
+
+    Stmt * postvisit( const CorunStmt * stmt ) {
+        assert( runnerBlockDecl );
+        if ( !stmt->stmt )
+            return nullptr;
+        
+        const CodeLocation & loc = stmt->location;
+        const string fnName = CorunFnNamer.newName();
+        const string objName = RunnerBlockNamer.newName();
+
+        // Generates:
+        // void __CFA_corun_lambda_() { ... stmt->stmt ... }
+        Stmt * runnerLambda = new DeclStmt( loc,
+            new FunctionDecl( loc,
+                fnName,                                             // name
+                {},                                                 // forall
+                {},                                                 // params
+                {},                                                 // return
+                new CompoundStmt( loc, { deepCopy(stmt->stmt) } )   // body
+            )
+        );
+
+        // Generates:
+        // runner_block __CFA_corun_block_;
+        Stmt * objDecl = new DeclStmt( loc,
+            new ObjectDecl( loc,
+                objName,
+                new StructInstType( runnerBlockDecl )
+            )
+        );
+
+        // Generates:
+        // __CFA_corun_block_{ __CFA_corun_lambda_ };
+        Stmt * threadStart = new ExprStmt( loc,
+            new UntypedExpr ( loc, 
+                new NameExpr( loc, "?{}" ),
+                {
+                    new NameExpr( loc, objName ),
+                    new NameExpr( loc, fnName )
+                }
+            )
+        );
+
+        stmtsToAddBefore.push_back( runnerLambda );
+        stmtsToAddBefore.push_back( objDecl );
+
+        return threadStart;
+    }
+};
+
+void implementCorun( TranslationUnit & translationUnit ) {
+    Pass<CorunKeyword>::run( translationUnit );
+}
+
+} // namespace Concurrency
Index: src/Concurrency/Corun.hpp
===================================================================
--- src/Concurrency/Corun.hpp	(revision eb779d5ca94c2de1db899969438189f4b2c05b4b)
+++ src/Concurrency/Corun.hpp	(revision eb779d5ca94c2de1db899969438189f4b2c05b4b)
@@ -0,0 +1,32 @@
+//
+// Cforall Version 1.0.0 Copyright (C) 2016 University of Waterloo
+//
+// The contents of this file are covered under the licence agreement in the
+// file "LICENCE" distributed with Cforall.
+//
+// Corun.hpp -- Implement concurrency constructs from their keywords.
+//
+// Author           : Colby Parsons
+// Created On       : Monday October 9 15:16:42 2023
+// Last Modified By :
+// Last Modified On :
+// Update Count     : 1
+//
+
+#pragma once
+
+
+class Declaration;
+namespace ast {
+	class TranslationUnit;
+}
+
+namespace Concurrency {
+	void implementCorun( ast::TranslationUnit & translationUnit );
+};
+
+// Local Variables: //
+// tab-width: 4 //
+// mode: c++ //
+// compile-command: "make install" //
+// End: //
Index: src/Concurrency/module.mk
===================================================================
--- src/Concurrency/module.mk	(revision 1d66a916f973e84743f24206d3aa6d6aaefa5634)
+++ src/Concurrency/module.mk	(revision eb779d5ca94c2de1db899969438189f4b2c05b4b)
@@ -18,4 +18,6 @@
 	Concurrency/Actors.cpp \
 	Concurrency/Actors.hpp \
+	Concurrency/Corun.cpp \
+	Concurrency/Corun.hpp \
 	Concurrency/KeywordsNew.cpp \
 	Concurrency/Keywords.cc \