1 files changed, 112 insertions, 0 deletions
diff --git a/misc/examples/coroutines/coroutines.c b/misc/examples/coroutines/coroutines.c
new file mode 100644
index 00000000..802a976a
--- /dev/null
+++ b/misc/examples/coroutines/coroutines.c
@@ -0,0 +1,112 @@
+#include <stc/coroutine.h>
+#include <stdio.h>
+#include <stdint.h>
+
+// Demonstrate to call another coroutine from a coroutine:
+// First create prime generator, then call fibonacci sequence:
+
+bool is_prime(long long i) {
+    for (long long j=2; j*j <= i; ++j)
+        if (i % j == 0) return false;
+    return true;
+}
+
+struct prime {
+    int count, idx;
+    long long result, pos;
+    int cco_state;
+};
+
+int prime(struct prime* g) {
+    cco_routine(g) {
+        if (g->result < 2) g->result = 2;
+        if (g->result == 2) {
+            if (g->count-- == 0) cco_return;
+            ++g->idx;
+            cco_yield();
+        }
+        g->result += !(g->result & 1);
+        for (g->pos = g->result; g->count > 0; g->pos += 2) {
+            if (is_prime(g->pos)) {
+                --g->count;
+                ++g->idx;
+                g->result = g->pos;
+                cco_yield();
+            }
+        }
+        cco_final:
+        printf("final prm\n");
+    }
+    return 0;
+}
+
+
+// Use coroutine to create a fibonacci sequence generator:
+
+struct fibonacci {
+    int count, idx;
+    long long result, b;
+    int cco_state;
+};
+
+int fibonacci(struct fibonacci* g) {
+    assert(g->count < 94);
+
+    long long sum;
+    cco_routine(g) {
+        g->idx = 0;
+        g->result = 0;
+        g->b = 1;
+        for (;;) {
+            if (g->count-- == 0)
+                cco_return;
+            if (++g->idx > 1) {
+                // NB! locals lasts only until next yield/await!
+                sum = g->result + g->b;
+                g->result = g->b;
+                g->b = sum;
+            }
+            cco_yield();
+        }
+        cco_final:
+        printf("final fib\n");
+    }
+    return 0;
+}
+
+// Combine
+
+struct combined {
+    struct prime prm;
+    struct fibonacci fib;
+    int cco_state;
+};
+
+int combined(struct combined* g) {
+    cco_routine(g) {
+        cco_await_call(prime(&g->prm));
+        cco_await_call(fibonacci(&g->fib));
+
+        // Reuse the g->prm context and extend the count:
+        g->prm.count = 8, g->prm.result += 2;
+        cco_reset(&g->prm);
+        cco_await_call(prime(&g->prm));
+
+        cco_final:
+        puts("final combined");
+    }
+    return 0;
+}
+
+int main(void)
+{
+    struct combined c = {.prm={.count=8}, .fib={14}};
+    int res;
+
+    cco_blocking_call(res = combined(&c)) {
+        if (res == CCO_YIELD)
+            printf("Prime(%d)=%lld, Fib(%d)=%lld\n", 
+                c.prm.idx, c.prm.result, 
+                c.fib.idx, c.fib.result);
+    }
+}