feat(parser): parse TEMPLATE declarations, template ids and parameter packs

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

5 files changed, 65 insertions, 4 deletions

diff --git a/include/cps/CodeGen.h b/include/cps/CodeGen.h
index e6281c5..283c4b1 100644
--- a/include/cps/CodeGen.h
+++ b/include/cps/CodeGen.h
@@ -25,6 +25,7 @@ class MemoryHandler;
 class ExceptionHandler;
 class CastExprAST;
 class NewExprAST;
+class TemplateDeclAST;
 
 class CodeGen {
     std::unique_ptr<llvm::LLVMContext> TheContext;
@@ -35,6 +36,8 @@ class CodeGen {
     size_t CurrentUnit = 0;
     size_t MainUnit = 0;
     IdentifierMap<size_t> TypeOwners;
+    struct TemplateDefinition { TemplateDeclAST *Decl; size_t OwnerUnit; };
+    IdentifierMap<std::vector<TemplateDefinition>> Templates;
     std::vector<IdentifierMap<SymbolInfo>> Exports;
     bool isVisible(size_t Owner) const;
     void selectUnit(size_t Unit);
diff --git a/include/cps/FunctionAST.h b/include/cps/FunctionAST.h
index 90ef5c4..9188015 100644
--- a/include/cps/FunctionAST.h
+++ b/include/cps/FunctionAST.h
@@ -23,6 +23,7 @@ struct ParamDecl {
     int Rank = 0; // 0 = scalar
     std::vector<std::pair<int64_t, int64_t>> DeclaredBounds;
     int Line = 0;
+    bool IsPack = false;
 };
 
 class PrototypeAST {
@@ -87,25 +88,31 @@ public:
 class CallExprAST : public ExprAST {
     std::string Callee;
     std::vector<std::unique_ptr<ExprAST>> Args;
+    std::vector<std::string> TemplateArgs;
 
 public:
-    CallExprAST(const std::string &Callee, std::vector<std::unique_ptr<ExprAST>> Args, int Line)
-        : ExprAST(Line), Callee(Callee), Args(std::move(Args)) {}
+    CallExprAST(const std::string &Callee, std::vector<std::unique_ptr<ExprAST>> Args, int Line,
+                std::vector<std::string> TemplateArgs = {})
+        : ExprAST(Line), Callee(Callee), Args(std::move(Args)), TemplateArgs(std::move(TemplateArgs)) {}
 
     const std::string &getCallee() const { return Callee; }
     const std::vector<std::unique_ptr<ExprAST>> &getArgs() const { return Args; }
+    const std::vector<std::string> &getTemplateArgs() const { return TemplateArgs; }
 };
 
 class CallStmtAST : public StmtAST {
     std::string Callee;
     std::vector<std::unique_ptr<ExprAST>> Args;
+    std::vector<std::string> TemplateArgs;
 
 public:
-    CallStmtAST(const std::string &Callee, std::vector<std::unique_ptr<ExprAST>> Args, int Line)
-        : StmtAST(Line), Callee(Callee), Args(std::move(Args)) {}
+    CallStmtAST(const std::string &Callee, std::vector<std::unique_ptr<ExprAST>> Args, int Line,
+                std::vector<std::string> TemplateArgs = {})
+        : StmtAST(Line), Callee(Callee), Args(std::move(Args)), TemplateArgs(std::move(TemplateArgs)) {}
 
     const std::string &getCallee() const { return Callee; }
     const std::vector<std::unique_ptr<ExprAST>> &getArgs() const { return Args; }
+    const std::vector<std::string> &getTemplateArgs() const { return TemplateArgs; }
 };
 
 
diff --git a/include/cps/Lexer.h b/include/cps/Lexer.h
index b514904..0ac2068 100644
--- a/include/cps/Lexer.h
+++ b/include/cps/Lexer.h
@@ -103,6 +103,7 @@ enum Token {
     tok_c_string = -611,
     tok_c_double = -612,
     tok_new = -613, tok_delete = -614,
+    tok_template = -615,
 
     tok_include = -650, tok_global = -651, tok_endglobal = -652,
     tok_include_obj = -653, tok_extern = -654,
diff --git a/include/cps/Parser.h b/include/cps/Parser.h
index eedc3f8..f2c0868 100644
--- a/include/cps/Parser.h
+++ b/include/cps/Parser.h
@@ -4,6 +4,7 @@
 #include "cps/AST.h"
 #include "cps/TypeAST.h"
 #include "cps/FunctionAST.h"
+#include "cps/TemplateAST.h"
 #include <cstdint>
 #include <vector>
 #include <initializer_list>
@@ -23,6 +24,8 @@ class Parser {
     std::vector<unsigned> CaseBodyDepths;
     unsigned NumErrors = 0;
     unsigned BlockDepth = 0; // ParseBlock nesting; 1 = top level
+    std::vector<TemplateParam> CurrentTemplate;
+    IdentifierSet PackNames;
 
     std::map<int, int> BinopPrecedence;
     IdentifierSet TypeNames = {
@@ -49,6 +52,9 @@ class Parser {
     std::unique_ptr<MemberCallExprAST> ParseMemberCall(
         const std::string &Name, std::vector<DesignatorAccess> Accesses, int Line);
     std::string ParseTypeName(bool AllowVoid = false);
+    std::optional<std::vector<std::string>> ParseTemplateArgs();
+    bool isTemplateCall();
+    bool isTemplatePack(const std::string &Name) const;
 
     std::unique_ptr<StmtAST> ParseStatement();
     std::unique_ptr<StmtAST> ParseStatementImpl();
@@ -70,6 +76,7 @@ class Parser {
     bool ParseDesignatorSuffix(std::vector<DesignatorAccess> &Out);
 
     std::unique_ptr<StmtAST> ParseTypeDecl();
+    std::unique_ptr<StmtAST> ParseTemplateDecl();
     std::optional<std::vector<RecordFieldDecl>> ParseRecordBody(
         const std::string &Name, int Line, int EndToken,
         std::vector<std::unique_ptr<FunctionDefAST>> *Methods = nullptr);
diff --git a/include/cps/TemplateAST.h b/include/cps/TemplateAST.h
new file mode 100644
index 0000000..c338b66
--- /dev/null
+++ b/include/cps/TemplateAST.h
@@ -0,0 +1,43 @@
+#pragma once
+#include "cps/FunctionAST.h"
+#include "cps/TypeAST.h"
+#include <memory>
+#include <string>
+#include <utility>
+#include <vector>
+
+namespace cps {
+
+struct TemplateParam {
+    std::string Name;
+    bool IsPack = false;
+    int Line = 0;
+};
+
+class TemplateDeclAST : public StmtAST {
+    std::vector<TemplateParam> Params;
+    std::unique_ptr<FunctionDefAST> Function;
+    std::unique_ptr<ClassTypeDeclAST> Class;
+public:
+    TemplateDeclAST(std::vector<TemplateParam> Params, std::unique_ptr<FunctionDefAST> Function)
+        : Params(std::move(Params)), Function(std::move(Function)) {}
+    TemplateDeclAST(std::vector<TemplateParam> Params, std::unique_ptr<ClassTypeDeclAST> Class)
+        : Params(std::move(Params)), Class(std::move(Class)) {}
+    const auto &getParams() const { return Params; }
+    const std::string &getName() const {
+        return Function ? Function->getProto()->getName() : Class->getName();
+    }
+    bool isVariadic() const { return !Params.empty() && Params.back().IsPack; }
+    FunctionDefAST *getFunction() const { return Function.get(); }
+    ClassTypeDeclAST *getClass() const { return Class.get(); }
+};
+
+class PackExpansionExprAST : public ExprAST {
+    std::string Name;
+public:
+    PackExpansionExprAST(std::string Name, int Line)
+        : ExprAST(Line), Name(std::move(Name)) {}
+    const std::string &getName() const { return Name; }
+};
+
+} // namespace cps