From 990bec78d30c5e23cd6aa83a6f98b1d4199bd8c3 Mon Sep 17 00:00:00 2001
From: Ben Burdette <bburdette@gmail.com>
Date: Sat, 8 Jan 2022 15:43:04 -0700
Subject: [PATCH] clear screen and show top debug trace

---
 src/libcmd/command.cc | 22 ++++++++++++++++++++++
 1 file changed, 22 insertions(+)

diff --git a/src/libcmd/command.cc b/src/libcmd/command.cc
index ed8f6d295..5848a15bf 100644
--- a/src/libcmd/command.cc
+++ b/src/libcmd/command.cc
@@ -77,8 +77,30 @@ ref<EvalState> EvalCommand::getEvalState()
                 searchPath, getEvalStore(), getStore());
         if (startReplOnEvalErrors)
             debuggerHook = [evalState{ref<EvalState>(evalState)}](const Error * error, const Env & env, const Expr & expr) {
+                std::cout << "\033[2J\033[1;1H";
+              
                 if (error)
                     printError("%s\n\n" ANSI_BOLD "Starting REPL to allow you to inspect the current state of the evaluator.\n" ANSI_NORMAL, error->what());
+                else 
+                {
+                    auto iter = evalState->debugTraces.begin();
+                    if (iter !=  evalState->debugTraces.end()) {
+                          std::cout << "\n" << "… " << iter->hint.str() << "\n";
+
+                          if (iter->pos.has_value() && (*iter->pos)) {
+                              auto pos = iter->pos.value();
+                              std::cout << "\n";
+                              printAtPos(pos, std::cout);
+
+                              auto loc = getCodeLines(pos);
+                              if (loc.has_value()) {
+                                  std::cout << "\n";
+                                  printCodeLines(std::cout, "", pos, *loc);
+                                  std::cout << "\n";
+                              }
+                          }
+                      }
+                }
 
                 if (expr.staticenv)
                 {