3 files changed, 23 insertions, 29 deletions

diff --git a/include/stc/algo/coroutine.h b/include/stc/algo/coroutine.h
index 6e36750d..da15aa5b 100644
--- a/include/stc/algo/coroutine.h
+++ b/include/stc/algo/coroutine.h
@@ -35,40 +35,41 @@ struct iterate {
     int y;
 };
 
-bool iterate(struct iterate* U) {
-    cco_begin(U);
-        for (U->x = 0; U->x < U->max_x; U->x++)
-            for (U->y = 0; U->y < U->max_y; U->y++)
-                cco_yield (true);
+bool iterate(struct iterate* I) {
+    cco_begin(I);
+        for (I->x = 0; I->x < I->max_x; I->x++)
+            for (I->y = 0; I->y < I->max_y; I->y++)
+                cco_yield(true);
 
         cco_final:
             puts("final");
-    cco_end(U);
-    return false;
+    cco_end(false);
 }
 
 int main(void) {
-    struct iterate it = {3, 3};
+    struct iterate it = {.max_x=3, .max_y=3};
     int n = 0;
     while (iterate(&it))
     {
         printf("%d %d\n", it.x, it.y);
-        if (++n == 20) { iterate(cco_stop(&it)); break; }
+        // example of early stop:
+        if (++n == 20) (void)cco_stop(&it); // signal to stop at next
     }
     return 0;
 }
 */
 #include <stc/ccommon.h>
 
-#define cco_begin(c) \
-    int *_state = &(c)->cco_state; \
+#define cco_begin(ctx) \
+    int *_state = &(ctx)->cco_state; \
     switch (*_state) { \
         case 0:
 
-#define cco_end() \
+#define cco_end(retval) \
         *_state = 0; break; \
         default: assert(!"missing cco_final: or illegal state"); \
-    }
+    } \
+    return retval
 
 #define cco_yield(retval) \
     do { \
@@ -76,15 +77,15 @@ int main(void) {
         case __LINE__:; \
     } while (0)
 
-#define cco_yield_coroutine(c, corocall, retval) \
+#define cco_yield_coroutine(ctx, corocall, retval) \
     do { \
         *_state = __LINE__; \
         c_PASTE(cco, __LINE__): corocall; return retval; \
-        case __LINE__:; if (cco_alive(c)) goto c_PASTE(cco, __LINE__); \
+        case __LINE__:; if (cco_alive(ctx)) goto c_PASTE(cco, __LINE__); \
     } while (0)
 
 #define cco_final case -1
-#define cco_alive(c) ((c) && (c)->cco_state > 0)
-#define cco_stop(c) ((c)->cco_state = ((c)->cco_state > 0 ? -1 : -2), c)
+#define cco_alive(ctx) ((ctx)->cco_state > 0)
+#define cco_stop(ctx) ((ctx)->cco_state = cco_alive(ctx) ? -1 : -2), ctx)
 
 #endif
diff --git a/misc/examples/coread.c b/misc/examples/coread.c
index 3d49c5df..4df80339 100644
--- a/misc/examples/coread.c
+++ b/misc/examples/coread.c
@@ -24,8 +24,7 @@ bool file_nextline(struct file_nextline* U)
             printf("finish\n");
             cstr_drop(&U->line);
             fclose(U->fp);
-    cco_end();
-    return false;
+    cco_end(false);
 }
 
 int main(void) {
@@ -33,9 +32,6 @@ int main(void) {
     int n = 0;
     while (file_nextline(&z)) {
         printf("%3d %s\n", ++n, cstr_str(&z.line));
-
-        // stop after 15 lines:
-        if (n == 15) (void)cco_stop(&z);
     }
     printf("state %d\n", z.cco_state);
 }
diff --git a/misc/examples/coroutines.c b/misc/examples/coroutines.c
index 5d2a178a..89b428ee 100644
--- a/misc/examples/coroutines.c
+++ b/misc/examples/coroutines.c
@@ -17,8 +17,7 @@ bool iterate(struct iterate* I) {
             for (I->y = 0; I->y < I->max_y; I->y++)
                 cco_yield(true);
         cco_final:
-    cco_end();
-    return false;
+    cco_end(false);
 }
 
 // Use coroutine to create a fibonacci sequence generator:
@@ -42,9 +41,7 @@ int64_t fibonacci(struct fibonacci* F) {
             F->b = sum;
         }
         cco_final:
-    cco_end();
-
-    return -1;
+    cco_end(-1);
 }
 
 // Combine
@@ -60,10 +57,10 @@ bool combine(struct combine* C) {
         cco_yield_coroutine(&C->it, iterate(&C->it), true);
         cco_yield_coroutine(&C->fib, fibonacci(&C->fib), true);
         // May reuse the C->it context; state has been reset to 0.
+        C->it.max_x = 2; C->it.max_y = 2;
         cco_yield_coroutine(&C->it, iterate(&C->it), true);
         cco_final: puts("final");
-    cco_end();
-    return false;
+    cco_end(false);
 }
 
 int main(void) {