From 951af56540ce995cf8526bf1671c5964ba06116b Mon Sep 17 00:00:00 2001
From: Yuichi Nishiwaki <yuichi.nishiwaki@gmail.com>
Date: Wed, 24 Sep 2014 14:53:09 +0900
Subject: [PATCH 01/13] publish struct pic_escape

---
 cont.c                | 17 -----------------
 include/picrin/cont.h | 17 +++++++++++++++++
 2 files changed, 17 insertions(+), 17 deletions(-)

diff --git a/cont.c b/cont.c
index 8ee36b33..496503cc 100644
--- a/cont.c
+++ b/cont.c
@@ -57,23 +57,6 @@ pic_dynamic_wind(pic_state *pic, struct pic_proc *in, struct pic_proc *thunk, st
   return val;
 }
 
-struct pic_escape {
-  jmp_buf jmp;
-
-  bool valid;
-
-  struct pic_winder *wind;
-
-  ptrdiff_t sp_offset;
-  ptrdiff_t ci_offset;
-  ptrdiff_t xp_offset;
-  int arena_idx;
-
-  pic_code *ip;
-
-  pic_value results;
-};
-
 static int
 save_point(pic_state *pic, struct pic_escape *escape)
 {
diff --git a/include/picrin/cont.h b/include/picrin/cont.h
index c0868f79..f49d6595 100644
--- a/include/picrin/cont.h
+++ b/include/picrin/cont.h
@@ -9,6 +9,23 @@
 extern "C" {
 #endif
 
+struct pic_escape {
+  jmp_buf jmp;
+
+  bool valid;
+
+  struct pic_winder *wind;
+
+  ptrdiff_t sp_offset;
+  ptrdiff_t ci_offset;
+  ptrdiff_t xp_offset;
+  int arena_idx;
+
+  pic_code *ip;
+
+  pic_value results;
+};
+
 void pic_wind(pic_state *, struct pic_winder *, struct pic_winder *);
 pic_value pic_dynamic_wind(pic_state *, struct pic_proc *, struct pic_proc *, struct pic_proc *);
 

From 07f24db66f02c3e7e138dc323111fc5bde985567 Mon Sep 17 00:00:00 2001
From: Yuichi Nishiwaki <yuichi.nishiwaki@gmail.com>
Date: Wed, 24 Sep 2014 14:57:49 +0900
Subject: [PATCH 02/13] add make_escape

---
 cont.c | 29 ++++++++++++++++++-----------
 1 file changed, 18 insertions(+), 11 deletions(-)

diff --git a/cont.c b/cont.c
index 496503cc..1066dd89 100644
--- a/cont.c
+++ b/cont.c
@@ -109,10 +109,26 @@ escape_call(pic_state *pic)
   load_point(pic, e->data);
 }
 
+static struct pic_proc *
+make_escape(pic_state *pic, struct pic_escape *escape)
+{
+  static const pic_data_type escape_type = { "escape", pic_free, NULL };
+  struct pic_proc *cont;
+  struct pic_data *e;
+
+  cont = pic_make_proc(pic, escape_call, "<escape-procedure>");
+
+  e = pic_data_alloc(pic, &escape_type, escape);
+
+  /* save the escape continuation in proc */
+  pic_attr_set(pic, cont, "@@escape", pic_obj_value(e));
+
+  return cont;
+}
+
 pic_value
 pic_escape(pic_state *pic, struct pic_proc *proc)
 {
-  static const pic_data_type escape_type = { "escape", pic_free, NULL };
   struct pic_escape *escape;
 
   escape = pic_alloc(pic, sizeof(struct pic_escape));
@@ -121,18 +137,9 @@ pic_escape(pic_state *pic, struct pic_proc *proc)
     return pic_values_by_list(pic, escape->results);
   }
   else {
-    struct pic_proc *c;
     pic_value val;
-    struct pic_data *e;
 
-    c = pic_make_proc(pic, escape_call, "<escape-procedure>");
-
-    e = pic_data_alloc(pic, &escape_type, escape);
-
-    /* save the escape continuation in proc */
-    pic_attr_set(pic, c, "@@escape", pic_obj_value(e));
-
-    val = pic_apply1(pic, proc, pic_obj_value(c));
+    val = pic_apply1(pic, proc, pic_obj_value(make_escape(pic, escape)));
 
     escape->valid = false;
 

From c965f254cb05ca49ab32d18f37838cb50831ddf5 Mon Sep 17 00:00:00 2001
From: Yuichi Nishiwaki <yuichi.nishiwaki@gmail.com>
Date: Wed, 24 Sep 2014 15:33:21 +0900
Subject: [PATCH 03/13] missing validation flag change

---
 cont.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/cont.c b/cont.c
index 1066dd89..bc1a6c17 100644
--- a/cont.c
+++ b/cont.c
@@ -92,6 +92,8 @@ load_point(pic_state *pic, struct pic_escape *escape)
   pic->arena_idx = escape->arena_idx;
   pic->ip = escape->ip;
 
+  escape->valid = false;
+
   longjmp(escape->jmp, 1);
 }
 

From e38732995e14bd7e89f12a8a3a830213934f06e1 Mon Sep 17 00:00:00 2001
From: Yuichi Nishiwaki <yuichi.nishiwaki@gmail.com>
Date: Wed, 24 Sep 2014 15:34:46 +0900
Subject: [PATCH 04/13] publish continuation internal APIs

---
 cont.c                | 18 +++++++++---------
 include/picrin/cont.h |  5 +++++
 2 files changed, 14 insertions(+), 9 deletions(-)

diff --git a/cont.c b/cont.c
index bc1a6c17..2c109c67 100644
--- a/cont.c
+++ b/cont.c
@@ -57,8 +57,8 @@ pic_dynamic_wind(pic_state *pic, struct pic_proc *in, struct pic_proc *thunk, st
   return val;
 }
 
-static int
-save_point(pic_state *pic, struct pic_escape *escape)
+int
+pic_save_point(pic_state *pic, struct pic_escape *escape)
 {
   escape->valid = true;
 
@@ -75,8 +75,8 @@ save_point(pic_state *pic, struct pic_escape *escape)
   return setjmp(escape->jmp);
 }
 
-noreturn static void
-load_point(pic_state *pic, struct pic_escape *escape)
+noreturn void
+pic_load_point(pic_state *pic, struct pic_escape *escape)
 {
   if (! escape->valid) {
     pic_errorf(pic, "calling dead escape continuation");
@@ -108,11 +108,11 @@ escape_call(pic_state *pic)
 
   e = pic_data_ptr(pic_attr_ref(pic, pic_get_proc(pic), "@@escape"));
 
-  load_point(pic, e->data);
+  pic_load_point(pic, e->data);
 }
 
-static struct pic_proc *
-make_escape(pic_state *pic, struct pic_escape *escape)
+struct pic_proc *
+pic_make_cont(pic_state *pic, struct pic_escape *escape)
 {
   static const pic_data_type escape_type = { "escape", pic_free, NULL };
   struct pic_proc *cont;
@@ -135,13 +135,13 @@ pic_escape(pic_state *pic, struct pic_proc *proc)
 
   escape = pic_alloc(pic, sizeof(struct pic_escape));
 
-  if (save_point(pic, escape)) {
+  if (pic_save_point(pic, escape)) {
     return pic_values_by_list(pic, escape->results);
   }
   else {
     pic_value val;
 
-    val = pic_apply1(pic, proc, pic_obj_value(make_escape(pic, escape)));
+    val = pic_apply1(pic, proc, pic_obj_value(pic_make_cont(pic, escape)));
 
     escape->valid = false;
 
diff --git a/include/picrin/cont.h b/include/picrin/cont.h
index f49d6595..6fd6fda8 100644
--- a/include/picrin/cont.h
+++ b/include/picrin/cont.h
@@ -26,6 +26,11 @@ struct pic_escape {
   pic_value results;
 };
 
+int pic_save_point(pic_state *, struct pic_escape *);
+noreturn void pic_load_point(pic_state *, struct pic_escape *);
+
+struct pic_proc *pic_make_cont(pic_state *, struct pic_escape *);
+
 void pic_wind(pic_state *, struct pic_winder *, struct pic_winder *);
 pic_value pic_dynamic_wind(pic_state *, struct pic_proc *, struct pic_proc *, struct pic_proc *);
 

From c7c771c861ff656b96086e4f7c8cb230d5cd20e7 Mon Sep 17 00:00:00 2001
From: Yuichi Nishiwaki <yuichi.nishiwaki@gmail.com>
Date: Wed, 24 Sep 2014 15:35:00 +0900
Subject: [PATCH 05/13] refactor pic_push_try. use raw continuation API

---
 error.c | 54 ++++++++++++++++++++++++++----------------------------
 1 file changed, 26 insertions(+), 28 deletions(-)

diff --git a/error.c b/error.c
index 978ff962..aa2e8e42 100644
--- a/error.c
+++ b/error.c
@@ -85,39 +85,37 @@ native_exception_handler(pic_state *pic)
   UNREACHABLE();
 }
 
-static pic_value
-native_push_try(pic_state *pic)
-{
-  struct pic_proc *cont, *handler;
-  size_t xp_len, xp_offset;
-
-  pic_get_args(pic, "l", &cont);
-
-  handler = pic_make_proc(pic, native_exception_handler, "(native-exception-handler)");
-
-  pic_attr_set(pic, handler, "@@escape", pic_obj_value(cont));
-
-  if (pic->xp >= pic->xpend) {
-    xp_len = (pic->xpend - pic->xpbase) * 2;
-    xp_offset = pic->xp - pic->xpbase;
-    pic->xpbase = pic_realloc(pic, pic->xpbase, sizeof(struct pic_proc *) * xp_len);
-    pic->xp = pic->xpbase + xp_offset;
-    pic->xpend = pic->xpbase + xp_len;
-  }
-
-  *pic->xp++ = handler;
-
-  return pic_true_value();
-}
-
 bool
 pic_push_try(pic_state *pic)
 {
-  pic_value val;
+  struct pic_escape *escape;
 
-  val = pic_escape(pic, pic_make_proc(pic, native_push_try, "(native-push-try)"));
+  escape = pic_alloc(pic, sizeof(struct pic_escape));
 
-  return pic_test(val);
+  if (pic_save_point(pic, escape)) {
+    return false;
+  } else {
+    struct pic_proc *cont, *handler;
+    size_t xp_len, xp_offset;
+
+    cont = pic_make_cont(pic, escape);
+
+    handler = pic_make_proc(pic, native_exception_handler, "(native-exception-handler)");
+
+    pic_attr_set(pic, handler, "@@escape", pic_obj_value(cont));
+
+    if (pic->xp >= pic->xpend) {
+      xp_len = (pic->xpend - pic->xpbase) * 2;
+      xp_offset = pic->xp - pic->xpbase;
+      pic->xpbase = pic_realloc(pic, pic->xpbase, sizeof(struct pic_proc *) * xp_len);
+      pic->xp = pic->xpbase + xp_offset;
+      pic->xpend = pic->xpbase + xp_len;
+    }
+
+    *pic->xp++ = handler;
+
+    return true;
+  }
 }
 
 void

From 7c5fb70e735078e4dc9d61cf9bc631982e758bc9 Mon Sep 17 00:00:00 2001
From: Yuichi Nishiwaki <yuichi.nishiwaki@gmail.com>
Date: Wed, 24 Sep 2014 15:59:23 +0900
Subject: [PATCH 06/13] mark invalid flag

---
 error.c | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/error.c b/error.c
index aa2e8e42..02ec75a6 100644
--- a/error.c
+++ b/error.c
@@ -10,6 +10,7 @@
 #include "picrin/pair.h"
 #include "picrin/proc.h"
 #include "picrin/cont.h"
+#include "picrin/data.h"
 #include "picrin/string.h"
 #include "picrin/error.h"
 
@@ -121,7 +122,13 @@ pic_push_try(pic_state *pic)
 void
 pic_pop_try(pic_state *pic)
 {
-  --pic->xp;
+  struct pic_data *e;
+
+  assert(pic->xp > pic->xpbase);
+
+  e = pic_data_ptr(pic_attr_ref(pic, pic_proc_ptr(pic_attr_ref(pic, *--pic->xp, "@@escape")), "@@escape"));
+
+  ((struct pic_escape *)e->data)->valid = false;
 }
 
 struct pic_error *

From cb2157bbaee2fcded4feebaa46c10551426e10d7 Mon Sep 17 00:00:00 2001
From: Yuichi Nishiwaki <yuichi.nishiwaki@gmail.com>
Date: Wed, 24 Sep 2014 18:43:20 +0900
Subject: [PATCH 07/13] s/pic_make_cont/pic_make_econt/g

---
 cont.c                | 4 ++--
 error.c               | 2 +-
 include/picrin/cont.h | 2 +-
 3 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/cont.c b/cont.c
index 2c109c67..214602e5 100644
--- a/cont.c
+++ b/cont.c
@@ -112,7 +112,7 @@ escape_call(pic_state *pic)
 }
 
 struct pic_proc *
-pic_make_cont(pic_state *pic, struct pic_escape *escape)
+pic_make_econt(pic_state *pic, struct pic_escape *escape)
 {
   static const pic_data_type escape_type = { "escape", pic_free, NULL };
   struct pic_proc *cont;
@@ -141,7 +141,7 @@ pic_escape(pic_state *pic, struct pic_proc *proc)
   else {
     pic_value val;
 
-    val = pic_apply1(pic, proc, pic_obj_value(pic_make_cont(pic, escape)));
+    val = pic_apply1(pic, proc, pic_obj_value(pic_make_econt(pic, escape)));
 
     escape->valid = false;
 
diff --git a/error.c b/error.c
index 02ec75a6..92aa4710 100644
--- a/error.c
+++ b/error.c
@@ -99,7 +99,7 @@ pic_push_try(pic_state *pic)
     struct pic_proc *cont, *handler;
     size_t xp_len, xp_offset;
 
-    cont = pic_make_cont(pic, escape);
+    cont = pic_make_econt(pic, escape);
 
     handler = pic_make_proc(pic, native_exception_handler, "(native-exception-handler)");
 
diff --git a/include/picrin/cont.h b/include/picrin/cont.h
index 6fd6fda8..fd7bfea4 100644
--- a/include/picrin/cont.h
+++ b/include/picrin/cont.h
@@ -29,7 +29,7 @@ struct pic_escape {
 int pic_save_point(pic_state *, struct pic_escape *);
 noreturn void pic_load_point(pic_state *, struct pic_escape *);
 
-struct pic_proc *pic_make_cont(pic_state *, struct pic_escape *);
+struct pic_proc *pic_make_econt(pic_state *, struct pic_escape *);
 
 void pic_wind(pic_state *, struct pic_winder *, struct pic_winder *);
 pic_value pic_dynamic_wind(pic_state *, struct pic_proc *, struct pic_proc *, struct pic_proc *);

From d6b2fe05ceed53ce96e1db14017e097749d3e1a7 Mon Sep 17 00:00:00 2001
From: Yuichi Nishiwaki <yuichi.nishiwaki@gmail.com>
Date: Wed, 24 Sep 2014 19:24:02 +0900
Subject: [PATCH 08/13] add many many assertions (pic_pop_try)

---
 error.c | 14 +++++++++++---
 1 file changed, 11 insertions(+), 3 deletions(-)

diff --git a/error.c b/error.c
index 92aa4710..be1e2337 100644
--- a/error.c
+++ b/error.c
@@ -122,13 +122,21 @@ pic_push_try(pic_state *pic)
 void
 pic_pop_try(pic_state *pic)
 {
-  struct pic_data *e;
+  pic_value cont, escape;
 
   assert(pic->xp > pic->xpbase);
 
-  e = pic_data_ptr(pic_attr_ref(pic, pic_proc_ptr(pic_attr_ref(pic, *--pic->xp, "@@escape")), "@@escape"));
+  cont = pic_attr_ref(pic, *--pic->xp, "@@escape");
 
-  ((struct pic_escape *)e->data)->valid = false;
+  assert(pic_proc_p(cont));
+
+  escape = pic_attr_ref(pic, pic_proc_ptr(cont), "@@escape");
+
+  assert(pic_data_p(escape));
+
+  ((struct pic_escape *)pic_data_ptr(escape)->data)->valid = false;
+
+  puts("pop_try done;");
 }
 
 struct pic_error *

From 44c1debbbeae665ac118c34883d25b14e32cddff Mon Sep 17 00:00:00 2001
From: Yuichi Nishiwaki <yuichi.nishiwaki@gmail.com>
Date: Wed, 24 Sep 2014 19:24:19 +0900
Subject: [PATCH 09/13] don't do pop_try when an error was raised

---
 include/picrin/error.h | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/include/picrin/error.h b/include/picrin/error.h
index 5be65502..151cef12 100644
--- a/include/picrin/error.h
+++ b/include/picrin/error.h
@@ -29,8 +29,7 @@ struct pic_error *pic_make_error(pic_state *, pic_sym, const char *, pic_list);
     do
 #define pic_catch                               \
     while (pic_pop_try(pic), 0);                \
-  else                                          \
-    if (pic_pop_try(pic), 1)
+  else
 
 bool pic_push_try(pic_state *);
 void pic_pop_try(pic_state *);

From d6104b8b25860c78e7719066e898a29e9fabc26a Mon Sep 17 00:00:00 2001
From: Yuichi Nishiwaki <yuichi.nishiwaki@gmail.com>
Date: Wed, 24 Sep 2014 20:01:21 +0900
Subject: [PATCH 10/13] add noreturn mark

---
 error.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/error.c b/error.c
index be1e2337..e5dfd340 100644
--- a/error.c
+++ b/error.c
@@ -69,7 +69,7 @@ pic_errmsg(pic_state *pic)
   return pic_str_cstr(str);
 }
 
-static pic_value
+noreturn static pic_value
 native_exception_handler(pic_state *pic)
 {
   pic_value err;

From eb1e01d000dbdc607a2dc210cc737a1e7dbde4b6 Mon Sep 17 00:00:00 2001
From: Yuichi Nishiwaki <yuichi.nishiwaki@gmail.com>
Date: Wed, 24 Sep 2014 20:06:14 +0900
Subject: [PATCH 11/13] don't setjmp in pic_save_point

---
 cont.c                | 10 ++++------
 error.c               |  8 +++++---
 include/picrin/cont.h |  2 +-
 3 files changed, 10 insertions(+), 10 deletions(-)

diff --git a/cont.c b/cont.c
index 214602e5..a560fa72 100644
--- a/cont.c
+++ b/cont.c
@@ -57,7 +57,7 @@ pic_dynamic_wind(pic_state *pic, struct pic_proc *in, struct pic_proc *thunk, st
   return val;
 }
 
-int
+void
 pic_save_point(pic_state *pic, struct pic_escape *escape)
 {
   escape->valid = true;
@@ -71,8 +71,6 @@ pic_save_point(pic_state *pic, struct pic_escape *escape)
   escape->ip = pic->ip;
 
   escape->results = pic_undef_value();
-
-  return setjmp(escape->jmp);
 }
 
 noreturn void
@@ -131,11 +129,11 @@ pic_make_econt(pic_state *pic, struct pic_escape *escape)
 pic_value
 pic_escape(pic_state *pic, struct pic_proc *proc)
 {
-  struct pic_escape *escape;
+  struct pic_escape *escape = pic_alloc(pic, sizeof(struct pic_escape));
 
-  escape = pic_alloc(pic, sizeof(struct pic_escape));
+  pic_save_point(pic, escape);
 
-  if (pic_save_point(pic, escape)) {
+  if (setjmp(escape->jmp)) {
     return pic_values_by_list(pic, escape->results);
   }
   else {
diff --git a/error.c b/error.c
index e5dfd340..a0c811d2 100644
--- a/error.c
+++ b/error.c
@@ -89,11 +89,13 @@ native_exception_handler(pic_state *pic)
 bool
 pic_push_try(pic_state *pic)
 {
-  struct pic_escape *escape;
+  struct pic_escape *escape = pic_alloc(pic, sizeof(struct pic_escape));
 
-  escape = pic_alloc(pic, sizeof(struct pic_escape));
+  pic_save_point(pic, escape);
+
+  if (setjmp(escape->jmp)) {
+    puts("escaping");
 
-  if (pic_save_point(pic, escape)) {
     return false;
   } else {
     struct pic_proc *cont, *handler;
diff --git a/include/picrin/cont.h b/include/picrin/cont.h
index fd7bfea4..0b29cfda 100644
--- a/include/picrin/cont.h
+++ b/include/picrin/cont.h
@@ -26,7 +26,7 @@ struct pic_escape {
   pic_value results;
 };
 
-int pic_save_point(pic_state *, struct pic_escape *);
+void pic_save_point(pic_state *, struct pic_escape *);
 noreturn void pic_load_point(pic_state *, struct pic_escape *);
 
 struct pic_proc *pic_make_econt(pic_state *, struct pic_escape *);

From d6c6427ff77faf93d2168ff09eac95aebb80769f Mon Sep 17 00:00:00 2001
From: Yuichi Nishiwaki <yuichi.nishiwaki@gmail.com>
Date: Wed, 24 Sep 2014 20:21:28 +0900
Subject: [PATCH 12/13] don't setjmp in pic_push_try

---
 error.c                | 44 ++++++++++++++----------------------------
 include/picrin/error.h | 18 ++++++++++++-----
 2 files changed, 28 insertions(+), 34 deletions(-)

diff --git a/error.c b/error.c
index a0c811d2..90d74572 100644
--- a/error.c
+++ b/error.c
@@ -86,39 +86,27 @@ native_exception_handler(pic_state *pic)
   UNREACHABLE();
 }
 
-bool
-pic_push_try(pic_state *pic)
+void
+pic_push_try(pic_state *pic, struct pic_escape *escape)
 {
-  struct pic_escape *escape = pic_alloc(pic, sizeof(struct pic_escape));
+  struct pic_proc *cont, *handler;
+  size_t xp_len, xp_offset;
 
-  pic_save_point(pic, escape);
+  cont = pic_make_econt(pic, escape);
 
-  if (setjmp(escape->jmp)) {
-    puts("escaping");
+  handler = pic_make_proc(pic, native_exception_handler, "(native-exception-handler)");
 
-    return false;
-  } else {
-    struct pic_proc *cont, *handler;
-    size_t xp_len, xp_offset;
+  pic_attr_set(pic, handler, "@@escape", pic_obj_value(cont));
 
-    cont = pic_make_econt(pic, escape);
-
-    handler = pic_make_proc(pic, native_exception_handler, "(native-exception-handler)");
-
-    pic_attr_set(pic, handler, "@@escape", pic_obj_value(cont));
-
-    if (pic->xp >= pic->xpend) {
-      xp_len = (pic->xpend - pic->xpbase) * 2;
-      xp_offset = pic->xp - pic->xpbase;
-      pic->xpbase = pic_realloc(pic, pic->xpbase, sizeof(struct pic_proc *) * xp_len);
-      pic->xp = pic->xpbase + xp_offset;
-      pic->xpend = pic->xpbase + xp_len;
-    }
-
-    *pic->xp++ = handler;
-
-    return true;
+  if (pic->xp >= pic->xpend) {
+    xp_len = (pic->xpend - pic->xpbase) * 2;
+    xp_offset = pic->xp - pic->xpbase;
+    pic->xpbase = pic_realloc(pic, pic->xpbase, sizeof(struct pic_proc *) * xp_len);
+    pic->xp = pic->xpbase + xp_offset;
+    pic->xpend = pic->xpbase + xp_len;
   }
+
+  *pic->xp++ = handler;
 }
 
 void
@@ -137,8 +125,6 @@ pic_pop_try(pic_state *pic)
   assert(pic_data_p(escape));
 
   ((struct pic_escape *)pic_data_ptr(escape)->data)->valid = false;
-
-  puts("pop_try done;");
 }
 
 struct pic_error *
diff --git a/include/picrin/error.h b/include/picrin/error.h
index 151cef12..784b95f8 100644
--- a/include/picrin/error.h
+++ b/include/picrin/error.h
@@ -9,6 +9,8 @@
 extern "C" {
 #endif
 
+#include "picrin/cont.h"
+
 struct pic_error {
   PIC_OBJECT_HEADER
   pic_sym type;
@@ -25,13 +27,19 @@ struct pic_error *pic_make_error(pic_state *, pic_sym, const char *, pic_list);
 /* do not return from try block! */
 
 #define pic_try                                 \
-  if (pic_push_try(pic))                        \
+  pic_try_(GENSYM(escape))
+#define pic_try_(escape)                                                \
+  struct pic_escape *escape = pic_alloc(pic, sizeof(struct pic_escape)); \
+  pic_save_point(pic, escape);                                          \
+  if (setjmp(escape->jmp) == 0) {                                       \
+    pic_push_try(pic, escape);                                          \
     do
-#define pic_catch                               \
-    while (pic_pop_try(pic), 0);                \
-  else
+#define pic_catch                                         \
+    while (0);                                            \
+    pic_pop_try(pic);                                     \
+  } else
 
-bool pic_push_try(pic_state *);
+void pic_push_try(pic_state *, struct pic_escape *);
 void pic_pop_try(pic_state *);
 
 pic_value pic_raise_continuable(pic_state *, pic_value);

From a6d2491338ed4467077b21bbfd3bf2e5c2ab3ffc Mon Sep 17 00:00:00 2001
From: Yuichi Nishiwaki <yuichi.nishiwaki@gmail.com>
Date: Wed, 24 Sep 2014 20:27:16 +0900
Subject: [PATCH 13/13] don't perform longjmp in pic_load_point (for the
 symmetry)

---
 cont.c                | 6 +++---
 include/picrin/cont.h | 2 +-
 2 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/cont.c b/cont.c
index a560fa72..56e6263e 100644
--- a/cont.c
+++ b/cont.c
@@ -73,7 +73,7 @@ pic_save_point(pic_state *pic, struct pic_escape *escape)
   escape->results = pic_undef_value();
 }
 
-noreturn void
+void
 pic_load_point(pic_state *pic, struct pic_escape *escape)
 {
   if (! escape->valid) {
@@ -91,8 +91,6 @@ pic_load_point(pic_state *pic, struct pic_escape *escape)
   pic->ip = escape->ip;
 
   escape->valid = false;
-
-  longjmp(escape->jmp, 1);
 }
 
 noreturn static pic_value
@@ -107,6 +105,8 @@ escape_call(pic_state *pic)
   e = pic_data_ptr(pic_attr_ref(pic, pic_get_proc(pic), "@@escape"));
 
   pic_load_point(pic, e->data);
+
+  longjmp(((struct pic_escape *)e->data)->jmp, 1);
 }
 
 struct pic_proc *
diff --git a/include/picrin/cont.h b/include/picrin/cont.h
index 0b29cfda..3e948f73 100644
--- a/include/picrin/cont.h
+++ b/include/picrin/cont.h
@@ -27,7 +27,7 @@ struct pic_escape {
 };
 
 void pic_save_point(pic_state *, struct pic_escape *);
-noreturn void pic_load_point(pic_state *, struct pic_escape *);
+void pic_load_point(pic_state *, struct pic_escape *);
 
 struct pic_proc *pic_make_econt(pic_state *, struct pic_escape *);