From c35170a83d3c507e2129df1a54728ff9f305e098 Mon Sep 17 00:00:00 2001
From: Jhon Pedroza <jhonfpedroza@gmail.com>
Date: Mon, 19 Aug 2019 00:25:12 -0500
Subject: [PATCH] Added flags to lispy class. Properly clear screen

---
 builtin.cpp |  3 ++-
 lenv.hpp    |  2 ++
 lispy.cpp   | 18 ++++++++++++++++--
 lispy.hpp   |  8 +++++++-
 4 files changed, 27 insertions(+), 4 deletions(-)

diff --git a/builtin.cpp b/builtin.cpp
index 6b48a58..6448153 100644
--- a/builtin.cpp
+++ b/builtin.cpp
@@ -721,7 +721,8 @@ namespace repl {
 lval *clear(lenv *e, lval *a) {
     LASSERT_NUM_ARGS("clear", a, 0)
 
-    linenoiseClearScreen();
+    auto lspy = lispy::instance();
+    lspy->flags |= LISPY_FLAG_CLEAR_OUTPUT;
 
     return lval::sexpr();
 }
diff --git a/lenv.hpp b/lenv.hpp
index 6d8211c..54d4426 100644
--- a/lenv.hpp
+++ b/lenv.hpp
@@ -21,9 +21,11 @@ struct lenv {
 
     std::vector<std::string> keys() const;
     std::vector<const std::string *> keys(const std::string &prefix) const;
+
     lval *get(const std::string &sym) const;
     void put(const std::string &sym, const lval *const val);
     void def(const std::string &sym, const lval *const val);
+
     void add_builtin_function(const std::string &name, lbuiltin func);
     void add_builtin_macro(const std::string &name, lbuiltin func);
     void add_builtin_command(const std::string &name, lbuiltin func);
diff --git a/lispy.cpp b/lispy.cpp
index 5fb7876..42f0ca2 100644
--- a/lispy.cpp
+++ b/lispy.cpp
@@ -13,7 +13,8 @@ using std::vector;
 lispy *lispy::_instance = nullptr;
 
 lispy::lispy()
-    : cmd_line("The Lispy interpreter", ' ', LISPY_VERSION),
+    : flags(LISPY_NO_FLAGS),
+      cmd_line("The Lispy interpreter", ' ', LISPY_VERSION),
       interactive_arg("i", "interactive",
                       "Run REPL, even when -e is present or files are given",
                       false),
@@ -71,11 +72,13 @@ int lispy::run(int argc, char *argv[]) {
         }
 
         if ((evals.empty() && files.empty()) || interactive) {
+            flags |= LISPY_FLAG_INTERACTIVE;
             builtin::add_builtin_commands(&env);
             run_interactive();
         }
     } catch (TCLAP::ArgException &e) {
         cerr << "Error: " << e.error() << " for arg " << e.argId() << endl;
+        return 1;
     }
 
     return 0;
@@ -142,9 +145,10 @@ void lispy::run_interactive() {
         if (mpc_parse("<stdin>", input, lispy_parser, &r)) {
             lval *result = lval::read((mpc_ast_t *)r.output);
             result = lval::eval(&env, result);
-            cout << *result << endl;
+            bool break_loop = process_interactive_result(result);
             delete result;
             mpc_ast_delete((mpc_ast_t *)r.output);
+            if (break_loop) break;
         } else {
             /* Otherwise Print the Error */
             mpc_err_print(r.error);
@@ -158,6 +162,16 @@ void lispy::run_interactive() {
     linenoiseHistoryFree();
 }
 
+bool lispy::process_interactive_result(lval *result) {
+    if (flags & LISPY_FLAG_CLEAR_OUTPUT) {
+        linenoiseClearScreen();
+        return false;
+    }
+
+    cout << *result << endl;
+    return false;
+}
+
 bool lispy::load_files(const vector<string> &files) {
     for (auto file: files) {
         lval *args = lval::sexpr({new lval(file)});
diff --git a/lispy.hpp b/lispy.hpp
index c47cac1..395a93a 100644
--- a/lispy.hpp
+++ b/lispy.hpp
@@ -6,6 +6,10 @@
 #include "lenv.hpp"
 #include "mpc.h"
 
+#define LISPY_NO_FLAGS 0x0
+#define LISPY_FLAG_INTERACTIVE 0x1
+#define LISPY_FLAG_CLEAR_OUTPUT 0x2
+
 class lispy {
    public:
     lispy();
@@ -16,15 +20,17 @@ class lispy {
     int run(int argc, char *argv[]);
     mpc_parser_t *parser();
 
+    uint flags;
+
    private:
     lenv env;
     static lispy *_instance;
 
     bool load_prelude();
     void run_interactive();
+    bool process_interactive_result(lval *result);
     bool load_files(const std::vector<std::string> &files);
     bool eval_strings(const std::vector<std::string> &strings);
-    void register_completion_hook();
 
     friend void completion_hook(char const *prefix, linenoiseCompletions *lc);