feat(codegen): instantiate function templates by deduction

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

1 files changed, 32 insertions, 0 deletions

diff --git a/lib/CodeGen/TemplateClone.h b/lib/CodeGen/TemplateClone.h
new file mode 100644
index 0000000..a0f196f
--- /dev/null
+++ b/lib/CodeGen/TemplateClone.h
@@ -0,0 +1,32 @@
+#pragma once
+#include "cps/TemplateAST.h"
+#include "cps/Identifier.h"
+#include <functional>
+
+namespace cps::detail {
+
+using TemplateBindings = IdentifierMap<std::vector<std::string>>;
+
+// Clones own all children; source ASTs remain reusable for later instances.
+class TemplateClone {
+    const TemplateBindings &Bindings;
+    IdentifierMap<std::vector<std::string>> PackNames;
+    std::function<void(int, const std::string &)> Error;
+    bool Failed = false;
+    void fail(int Line, const std::string &Message);
+    std::vector<std::unique_ptr<ExprAST>> arguments(const std::vector<std::unique_ptr<ExprAST>> &Args);
+    std::vector<std::unique_ptr<StmtAST>> body(const std::vector<std::unique_ptr<StmtAST>> &Body);
+    std::unique_ptr<ExprAST> expression(ExprAST *Expr);
+    std::unique_ptr<StmtAST> statement(StmtAST *Stmt);
+public:
+    TemplateClone(const TemplateBindings &Bindings,
+                  std::function<void(int, const std::string &)> Error)
+        : Bindings(Bindings), Error(std::move(Error)) {}
+    std::string type(const std::string &Name);
+    std::unique_ptr<FunctionDefAST> function(const FunctionDefAST *Source,
+        const std::string &Name, const std::string &OwnerClass = {});
+    std::unique_ptr<ClassTypeDeclAST> klass(const ClassTypeDeclAST *Source,
+                                           const std::string &Name);
+};
+
+} // namespace cps::detail