use format lib

.gitmodules

@@ -0,0 +1,3 @@
+[submodule "external/fmt"]
+	path = external/fmt
+	url = https://github.com/fmtlib/fmt.git

CMakeLists.txt

@@ -4,9 +4,13 @@ cmake_minimum_required(VERSION 3.16)
 project(rin)
 
 set(CMAKE_CXX_STANDARD 17)
+set(CMAKE_POSITION_INDEPENDENT_CODE ON)
 
 enable_testing()
 
+add_subdirectory(external/fmt)
+include_directories(external/fmt/include)
+
 find_package(LLVM REQUIRED CONFIG)
 
 add_definitions(${LLVM_DEFINITIONS})

include/ast.h

@@ -8,6 +8,8 @@
 
 namespace rin {
 
+class ParseException;
+
 class ASTNode {
 protected:
 	explicit ASTNode(const SourceRange &range): range(range) {}
@@ -96,15 +98,7 @@ class VarDeclNode : public ASTNode {
 		Ptr<ASTNode> type_node,
 		Ptr<ASTNode> value_node,
 		Type var_type
-	): ASTNode(range), name(std::move(name)),
-	   type_node(std::move(type_node)),
-	   value_node(std::move(value_node)),
-	   var_type(var_type) {
-		if (!(this->type_node || this->value_node))
-			throw CodegenException("A variable should have either a default value or a type annotation");
-		if ((var_type == Type::CONST || var_type == Type::VAL) && !this->value_node)
-			throw CodegenException("The default value of const variable should be given");
-	}
+	);
 
 	[[nodiscard]] const std::string &get_name() const { return name; }
 	[[nodiscard]] const ASTNode *get_value_node() const { return value_node.get(); }

include/codegen.h

@@ -1,6 +1,8 @@
 
 #pragma once
 
+#include "fmt/format.h"
+
 #include <llvm/IR/IRBuilder.h>
 
 #include "context.h"
@@ -14,10 +16,12 @@ class Function;
 class CodegenException : public std::exception {
 public:
 	[[nodiscard]] const char *what() const noexcept override { return msg.data(); }
-
-	explicit CodegenException(std::string msg): msg(std::move(msg)) {}
 private:
+	explicit CodegenException(std::string msg): msg(std::move(msg)) {}
+
 	std::string msg;
+
+	friend class Codegen;
 };
 
 class Codegen {
@@ -32,6 +36,11 @@ class Codegen {
 	Function::Static *get_function() const { return layers.back().function; }
 	llvm::IRBuilder<> *get_builder() const { return layers.back().builder.get(); }
 
+	template<class...Args>
+	[[noreturn]] void error(const char *pattern, Args&&...args) const {
+		throw CodegenException(fmt::format(pattern, std::forward<Args>(args)...));
+	}
+
 	void declare_value(const std::string &name, const Value &value) {
 		value_map.set(name, value);
 	}

include/parser.h

@@ -33,15 +33,21 @@ class Parser {
 private:
 	Ptr<ASTNode> take_prim_inner();
 
+	template<class...Args>
+	[[noreturn]] void error(const char *pattern, Args &&...args) const {
+		throw ParseException(fmt::format(pattern, std::forward<Args>(args)...));
+	}
+
 	void expect_end_of_stmt() {
 		// TODO error message
 		expect(lexer.take(), TokenKind::Semicolon);
 	}
 	Token expect(const Token &&token, TokenKind kind) const {
 		if (token.kind != kind) // TODO unlikely
-			throw ParseException(
-				"Expected " + token_kind::name(kind) + ", "
-				+ "got " + token.info(get_buffer())
+			error(
+				"Expected {}, got {}",
+				token_kind::name(kind),
+				token.info(get_buffer())
 			);
 		return token;
 	}
@@ -61,10 +67,11 @@ class Parser {
 			auto token = lexer.take();
 			if (token.kind == delimiter) continue;
 			if (token.kind == end) break;
-			throw ParseException(
-				"Expect " + token_kind::name(delimiter) +
-				" or " + token_kind::name(end) +
-				", got " + token.info(get_buffer())
+			error(
+				"Expected {} or {}, got {}",
+				token_kind::name(delimiter),
+				token_kind::name(end),
+				token.info(get_buffer())
 			);
 		}
 	}

main/CMakeLists.txt

@@ -3,4 +3,4 @@ aux_source_directory(. RIN_MAIN_SOURCE_FILES)
 
 add_library(rin SHARED ${RIN_MAIN_SOURCE_FILES})
 
-target_link_libraries(rin LLVM-12)
+target_link_libraries(rin fmt::fmt LLVM-12)