A lot of work

src/stack.h

@@ -0,0 +1,46 @@
+#ifndef INCLUDED_STACK_H
+#define INCLUDED_STACK_H
+
+#include "base.h"
+
+#define DEFAULT_MAX_LISP_EVAL_DEPTH   1000
+#define LOCAL_REFERENCES_BLOCK_LENGTH 64
+
+struct LocalReferencesBlock {
+    LispVal *refs[LOCAL_REFERENCES_BLOCK_LENGTH];
+};
+
+struct LocalReferences {
+    size_t num_blocks;
+    size_t num_refs;
+    struct LocalReferencesBlock **blocks;
+};
+
+struct StackFrame {
+    LispVal *name; // name of function call
+    LispVal *fobj; // the function object
+    LispVal *args; // arguments of the function call
+    LispVal *lexenv; // lexical environment (plist)
+    struct LocalReferences local_refs;
+};
+
+struct LispStack {
+    size_t max_depth;
+    size_t depth;
+    size_t first_clear_local_refs; // index of the first frame that has local
+                                   // refs that has not been grown
+    struct StackFrame *frames;
+};
+
+extern struct LispStack the_stack;
+
+static ALWAYS_INLINE struct StackFrame *LISP_STACK_TOP() {
+    return the_stack.depth ? &the_stack.frames[the_stack.depth - 1] : NULL;
+}
+
+void lisp_init_stack(void);
+void push_stack_frame(LispVal *name, LispVal *fobj, LispVal *args);
+void pop_stack_frame(void);
+void add_local_reference(LispVal *obj);
+
+#endif