From c2e0ec801502ae26dae3dfdd035ff10436cffedd Mon Sep 17 00:00:00 2001
From: Kaz Kylheku <kaz@kylheku.com>
Date: Sun, 6 Sep 2015 18:35:48 -0700
Subject: Allow evaluation from repl to be interrupted.

* eval.c (do_eval): Check for pending signals.

* parser.c (repl_intr): New static function.
(repl): Set up signal handler for SIGINT around REPL.

* signal.h (sig_deferred): declared.
(sig_check_fast): New inline function/macro.
A bit of a rearrangement here.
---
 eval.c   |  1 +
 parser.c |  7 +++++++
 signal.h | 11 ++++++++++-
 3 files changed, 18 insertions(+), 1 deletion(-)

diff --git a/eval.c b/eval.c
index 2afc431c..a31a9bce 100644
--- a/eval.c
+++ b/eval.c
@@ -955,6 +955,7 @@ static val do_eval(val form, val env, val ctx_form,
   debug_enter;
 
   debug_check(consp(form) ? form : ctx_form, env, nil, nil, nil, nil);
+  sig_check_fast();
 
   if (nilp(form)) {
     debug_return (nil);
diff --git a/parser.c b/parser.c
index c682f100..9a6217e8 100644
--- a/parser.c
+++ b/parser.c
@@ -473,6 +473,11 @@ static void provide_completions(const char *data,
   }
 }
 
+static val repl_intr(val signo, val async_p)
+{
+  uw_throw(error_s, lit("intr"));
+}
+
 val repl(val bindings, val in_stream, val out_stream)
 {
   val ifd = stream_get_prop(in_stream, fd_k);
@@ -489,6 +494,7 @@ val repl(val bindings, val in_stream, val out_stream)
   val result_hash = make_hash(nil, nil, nil);
   val done = nil;
   val counter = one;
+  val old_sig_handler = set_sig_handler(num(SIGINT), func_n2(repl_intr));
 
   reg_varl(result_hash_sym, result_hash);
 
@@ -570,6 +576,7 @@ val repl(val bindings, val in_stream, val out_stream)
     gc_hint(prompt);
   }
 
+  set_sig_handler(num(SIGINT), old_sig_handler);
   free(prompt_u8);
   free(line_u8);
   lino_free(ls);
diff --git a/signal.h b/signal.h
index 4b942275..2b6245e0 100644
--- a/signal.h
+++ b/signal.h
@@ -70,6 +70,14 @@ extern int debug_depth;
       sig_check();                              \
   } while(0)
 
+val sig_check(void);
+
+INLINE val sig_check_fast(void)
+{
+  extern volatile unsigned long sig_deferred;
+  return if2(sig_deferred, sig_check());
+}
+
 typedef struct {
   jmp_buf jb;
   sig_atomic_t se;
@@ -112,6 +120,8 @@ extern volatile sig_atomic_t async_sig_enabled;
 #define sig_restore_enable } while (0)
 #define sig_restore_disable } while (0)
 
+#define sig_check_fast() ((void) 0)
+
 typedef struct {
   jmp_buf jb;
   val de;
@@ -146,7 +156,6 @@ extern val dyn_env; /* eval.c */
 void sig_init(void);
 val set_sig_handler(val signo, val lambda);
 val get_sig_handler(val signo);
-val sig_check(void);
 #if HAVE_POSIX_SIGS
 int sig_mask(int how, const sigset_t *set, sigset_t *oldset);
 #endif
-- 
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