From a92eede277da1acdfa06da3c3c07f5fa8c64269b Mon Sep 17 00:00:00 2001
From: Riyyi <riyyi3@gmail.com>
Date: Sat, 25 Mar 2023 14:56:22 +0100
Subject: [PATCH] Main: Use GNU Readline library as the line editor

---
 CMakeLists.txt     |  2 +-
 src/readline.cpp   | 51 ++++++++++++++++++++++++++++++++++++++++++++++
 src/readline.h     | 29 ++++++++++++++++++++++++++
 src/step2_eval.cpp | 41 ++++++++++++++++---------------------
 4 files changed, 98 insertions(+), 25 deletions(-)
 create mode 100644 src/readline.cpp
 create mode 100644 src/readline.h

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 4f1d93b..3757967 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -68,7 +68,7 @@ file(GLOB_RECURSE PROJECT_SOURCES "src/*.cpp")
 add_executable(${PROJECT} ${PROJECT_SOURCES})
 target_include_directories(${PROJECT} PRIVATE
 	"src")
-target_link_libraries(${PROJECT} ruc)
+target_link_libraries(${PROJECT} readline ruc)
 
 # ------------------------------------------
 # Execute target
diff --git a/src/readline.cpp b/src/readline.cpp
new file mode 100644
index 0000000..a210b66
--- /dev/null
+++ b/src/readline.cpp
@@ -0,0 +1,51 @@
+/*
+ * Copyright (C) 2023 Riyyi
+ *
+ * SPDX-License-Identifier: MIT
+ */
+
+#include <cstdlib>  // std::free
+#include <iostream> // FILE
+#include <readline/history.h>
+#include <readline/readline.h>
+#include <readline/tilde.h>
+
+#include "ruc/format/color.h"
+
+#include "readline.h"
+
+namespace blaze {
+
+Readline::Readline(bool pretty_print, std::string_view history_path)
+	: m_pretty_print(pretty_print)
+	, m_history_path(history_path)
+{
+	if (!pretty_print) {
+		m_prompt = "user> ";
+	}
+	else {
+		m_prompt = format(fg(ruc::format::TerminalColor::Blue), "user>");
+		m_prompt += format(" \033[1m");
+	}
+
+	read_history(tilde_expand(history_path.data()));
+}
+
+bool Readline::get(std::string& output)
+{
+	char* line = readline(m_prompt.c_str());
+	if (line == nullptr) {
+		return false;
+	}
+
+	// Add input to in-memory history
+	add_history(line);
+	append_history(1, m_history_path.data());
+
+	output = line;
+	std::free(line);
+
+	return true;
+}
+
+} // namespace blaze
diff --git a/src/readline.h b/src/readline.h
new file mode 100644
index 0000000..da2d4d0
--- /dev/null
+++ b/src/readline.h
@@ -0,0 +1,29 @@
+/*
+ * Copyright (C) 2023 Riyyi
+ *
+ * SPDX-License-Identifier: MIT
+ */
+
+#pragma once
+
+#include <string>
+#include <string_view>
+
+#include "ruc/singleton.h"
+
+namespace blaze {
+
+class Readline {
+public:
+	Readline(bool pretty_print, std::string_view history_path);
+	virtual ~Readline() {}
+
+	bool get(std::string& output);
+
+private:
+	bool m_pretty_print { false };
+	std::string m_prompt;
+	std::string_view m_history_path;
+};
+
+} // namespace blaze
diff --git a/src/step2_eval.cpp b/src/step2_eval.cpp
index e0a546c..2a28b79 100644
--- a/src/step2_eval.cpp
+++ b/src/step2_eval.cpp
@@ -1,19 +1,18 @@
-#include <csignal>  // std::signal
-#include <cstdlib>  // std::exit
-#include <iostream> // std::cin
-#include <string>   // std::getline
+#include <csignal> // std::signal
+#include <cstdlib> // std::exit
+#include <string>
 #include <string_view>
 
-#include "environment.h"
-#include "eval.h"
 #include "ruc/argparser.h"
 #include "ruc/format/color.h"
 
 #include "ast.h"
-#include "error.h"
+#include "environment.h"
+#include "eval.h"
 #include "lexer.h"
 #include "printer.h"
 #include "reader.h"
+#include "readline.h"
 #include "settings.h"
 
 #if 1
@@ -58,7 +57,7 @@ auto rep(std::string_view input) -> void
 
 static auto cleanup(int signal) -> void
 {
-	print("\033[0m");
+	print("\033[0m\n");
 	std::exit(signal);
 }
 
@@ -67,12 +66,14 @@ auto main(int argc, char* argv[]) -> int
 	bool dump_lexer = false;
 	bool dump_reader = false;
 	bool pretty_print = false;
+	std::string_view history_path = "~/.mal-history";
 
 	// CLI arguments
 	ruc::ArgParser arg_parser;
 	arg_parser.addOption(dump_lexer, 'l', "dump-lexer", nullptr, nullptr);
 	arg_parser.addOption(dump_reader, 'r', "dump-reader", nullptr, nullptr);
 	arg_parser.addOption(pretty_print, 'c', "color", nullptr, nullptr);
+	arg_parser.addOption(history_path, 'h', "history", nullptr, nullptr);
 	arg_parser.parse(argc, argv);
 
 	// Set settings
@@ -84,26 +85,18 @@ auto main(int argc, char* argv[]) -> int
 	std::signal(SIGINT, cleanup);
 	std::signal(SIGTERM, cleanup);
 
-	while (true) {
-		if (!pretty_print) {
-			print("user> ");
-		}
-		else {
-			print(fg(ruc::format::TerminalColor::Blue), "user>");
-			print(" \033[1m");
-		}
-		std::string line;
-		std::getline(std::cin, line);
+	blaze::Readline readline(pretty_print, history_path);
+
+	std::string input;
+	while (readline.get(input)) {
 		if (pretty_print) {
 			print("\033[0m");
 		}
+		rep(input);
+	}
 
-		// Exit with Ctrl-D
-		if (std::cin.eof() || std::cin.fail()) {
-			break;
-		}
-
-		rep(line);
+	if (pretty_print) {
+		print("\033[0m");
 	}
 
 	return 0;