From c07a6ff6bf0ca074e542d2f86b350fe5394f9dfd Mon Sep 17 00:00:00 2001
From: Justin Ethier <justin.ethier@gmail.com>
Date: Thu, 13 Aug 2020 18:46:48 -0400
Subject: [PATCH] Demonstrate passing args to SCM func from C

---
 examples/call-scm-from-c/full-with-gc.scm | 18 ++++++++-----
 examples/call-scm-from-c/full.c           | 31 +++++++++++++----------
 examples/call-scm-from-c/full.h           |  2 +-
 3 files changed, 29 insertions(+), 22 deletions(-)

diff --git a/examples/call-scm-from-c/full-with-gc.scm b/examples/call-scm-from-c/full-with-gc.scm
index 5bce8b42..8c0cab5c 100644
--- a/examples/call-scm-from-c/full-with-gc.scm
+++ b/examples/call-scm-from-c/full-with-gc.scm
@@ -7,8 +7,9 @@
 
 (define lock (make-mutex))
 (define *done* #f)
-(define *dummy* signal-done) ;; Hack to prevent optimizing out signal-done
-(define *dummy2* sum-numbers) ;; Hack to prevent optimizing out signal-done
+(define *dummy* signal-done) ;; Hack to prevent optimizing out
+(define *dummy1* print-result) ;; Hack to prevent optimizing out
+(define *dummy2* sum-numbers) ;; Hack to prevent optimizing out
 
 (define-c start-c-thread
   "(void *data, int argc, closure _, object k)"
@@ -16,7 +17,7 @@
    return_closcall1(data, k, boolean_t); ")
 
 (define (sum-numbers)
- (let ((result 0))
+ (let ((result 500))
   (for-each
     (lambda (n)
       (set! result (+ result n)))
@@ -24,16 +25,19 @@
   (lambda X
     (list result 'result #(result)))))
 
-;(define (print-result
+(define (print-result fnc)
+  (let* ((result (fnc))
+         (num (car result)))
+    (write `(SCM result is ,num))
+    (newline)))
 
 ;; Signal (wait) that it is done, this is called from C
-(define (signal-done) ; obj)
- (let ((obj #t))
+(define (signal-done obj)
   (write `(Called from C set *done* to ,obj))
   (newline)
   (mutex-lock! lock)
   (set! *done* obj)
-  (mutex-unlock! lock)))
+  (mutex-unlock! lock))
 
 ;; More efficient to use a condition var here to signal ready,
 ;; but this is just an example
diff --git a/examples/call-scm-from-c/full.c b/examples/call-scm-from-c/full.c
index e9607112..ac9854cb 100644
--- a/examples/call-scm-from-c/full.c
+++ b/examples/call-scm-from-c/full.c
@@ -10,10 +10,11 @@
  */
 extern object __glo_signal_91done;
 extern object __glo_sum_91numbers;
+extern object __glo_print_91result;
 
 gc_thread_data local;
 
-void *Cyc_init_thread(object thread_and_thunk);
+void *Cyc_init_thread(object thread_and_thunk, int argc, object *args);
 
 /**
  * Code for the C thread. 
@@ -24,19 +25,27 @@ void *Cyc_init_thread(object thread_and_thunk);
  */
 void *c_thread(void *parent_thd)
 {
-  object obj;
+  object obj, fnc, args[1];
   printf("Hello from C thread\n");
   printf("C calling into SCM\n");
 
-  obj = scm_call_with_gc(parent_thd, __glo_sum_91numbers, boolean_t);
+  fnc = scm_call_with_gc(parent_thd, __glo_sum_91numbers, 0, NULL);
 
-  printf("C received: ");
+  printf("\nC received: ");
+  Cyc_write(NULL, fnc, stdout);
+  printf("\n");
+
+  args[0] = fnc;
+  obj = scm_call_with_gc(parent_thd, __glo_print_91result, 1, args);
+
+  printf("\nC received: ");
   Cyc_write(NULL, obj, stdout);
   printf("\n");
 
-  obj = scm_call_with_gc(parent_thd, __glo_signal_91done, boolean_t);
+  args[0] = boolean_t;
+  obj = scm_call_with_gc(parent_thd, __glo_signal_91done, 1, args);
 
-  printf("C received: ");
+  printf("\nC received: ");
   Cyc_write(NULL, obj, stdout);
   printf("\n");
   return NULL;
@@ -51,9 +60,6 @@ void *c_thread(void *parent_thd)
 
 void cleanup_and_return(gc_thread_data *thd, int argc, object k, object result)
 {
-  int i;
-  printf("cleanup and return %p result %p\n", &i, result);
-
   // Cleaup thread object per Cyc_exit_thread
   gc_remove_mutator(thd);
   ck_pr_cas_int((int *)&(thd->thread_state), CYC_THREAD_STATE_RUNNABLE,
@@ -71,9 +77,6 @@ void cleanup_and_return(gc_thread_data *thd, int argc, object k, object result)
  */
 void after_call_scm(gc_thread_data *thd, int argc, object k, object result)
 {
-  int i;
-  printf("after call scm %p result %p\n", &i, result);
-
   mclosure0(clo, cleanup_and_return);
   object buf[1]; buf[0] = result;
   GC(thd, &clo, buf, 1);
@@ -105,7 +108,7 @@ void after_call_scm(gc_thread_data *thd, int argc, object k, object result)
  * or re-allocated (EG: malloc) before returning it
  * to the C layer.
  */
-object scm_call_with_gc(gc_thread_data *parent_thd, object fnc, object arg)
+object scm_call_with_gc(gc_thread_data *parent_thd, object fnc, int argc, object *args)
 {
   jmp_buf l;
   local.gc_cont = NULL;
@@ -133,7 +136,7 @@ object scm_call_with_gc(gc_thread_data *parent_thd, object fnc, object arg)
   make_pair(thread_and_thunk, &vec, fnc); // TODO: OK we are not clearing vec[5]? I think so... 
 
   if (!setjmp(*(local.jmp_start))) {
-    Cyc_init_thread(&thread_and_thunk);
+    Cyc_init_thread(&thread_and_thunk, argc, args);
   }
 
   return local.gc_cont;
diff --git a/examples/call-scm-from-c/full.h b/examples/call-scm-from-c/full.h
index 08a634f0..b0656e20 100644
--- a/examples/call-scm-from-c/full.h
+++ b/examples/call-scm-from-c/full.h
@@ -1,4 +1,4 @@
 #include "cyclone/types.h"
 
 void start_c_thread(gc_thread_data *thd);
-object scm_call_with_gc(gc_thread_data *parent_thd, object fnc, object arg);
+object scm_call_with_gc(gc_thread_data *parent_thd, object fnc, int argc, object *args);