Implement 5.52 translate Scheme to C

shared/scm2c/stack.c

@@ -0,0 +1,41 @@
+#include <stdio.h>
+#include <stdlib.h>
+
+#include "stack.h"
+
+struct stack proc_stack;
+
+stack* create_stack(void) {
+    stack* s = malloc(sizeof(stack));
+    if (!s) exit(-1);
+    s->first = NULL;
+    return s;
+}
+
+void save(void *d, stack *s) {
+    stack_elem* elem = malloc(sizeof(stack_elem));
+    elem->value = d;
+
+    if (!s->first) {
+        elem->next = NULL;
+    } else {
+        elem->next = s->first;
+    }
+    s->first = elem;
+}
+
+void* restore(stack *s) {
+    void *r;
+    stack_elem *se;
+
+    if (!s->first) {
+        printf("stack empty!\n");
+        exit(-1);
+    }
+
+    se = s->first;
+    r = s->first->value;
+    s->first = se->next;
+    free(se);
+    return r;
+}