Make the REPL catch CONTROL-c when executing

Pressing CONTROL-c while something is executing, will not wait for
the result of that code to appear.  The code *will* however continue
to execute at the moment, because we do not have a way to force an
exception to be thrown in another thread.

Fixes RT #128900  *and* RT #128595

src/core/REPL.pm

@@ -318,6 +318,18 @@ do {
             my $prompt = self.interactive_prompt;
             my $code = "";
 
+            my $ctrl-c  = Promise.new;
+            my $running = False;
+            signal(SIGINT).tap: {
+                if $running {
+                    $running = False;
+                    $ctrl-c.keep("\nAborted")
+                }
+                else {
+                    exit 0;
+                }
+            }
+
             REPL: loop {
 
                 my $newcode = self.repl-read(~$prompt);
@@ -335,13 +347,36 @@ do {
                     next;
                 }
 
+                sub reset(--> Nil) {
+                    $code = '';
+                    $prompt = self.interactive_prompt;
+                }
+
                 my $*CTXSAVE := self;
                 my $*MAIN_CTX;
-
-                my $output := self.repl-eval(
-                    $code,
-                    :outer_ctx($!save_ctx),
-                    |%adverbs);
+                my $output;
+
+                await Promise.anyof(
+                  start {
+                      ENTER $running = True;
+                      LEAVE $running = False;
+                      CATCH {
+                          say $_;
+                          reset;
+                      }
+                      $output :=
+                        self.repl-eval($code,:outer_ctx($!save_ctx),|%adverbs);
+                  },
+                  $ctrl-c
+                );
+
+                if $ctrl-c.status == Kept {
+                    # XXX somehow kill the running thread
+                    say $ctrl-c.result;
+                    $ctrl-c = Promise.new;
+                    reset;
+                    next;
+                }
 
                 if self.input-incomplete($output) {
                     $prompt = '* ';
@@ -352,18 +387,16 @@ do {
                     $!save_ctx := $*MAIN_CTX;
                 }
 
-                $code = "";
-                $prompt = self.interactive_prompt;
+                reset;
 
                 # Only print the result if there wasn't some other output
                 if $initial_out_position == $*OUT.tell {
-                  self.repl-print($output);
+                    self.repl-print($output);
                 }
-
+                
                 CATCH {
                     say $_;
-                    $code = '';
-                    $prompt = self.interactive_prompt;
+                    reset;
                     next REPL;
                 }
             }