--- stack/stack.h	2002/03/11 08:53:00	1.11
+++ stack/stack.h	2002/03/17 11:26:35	1.16
@@ -25,10 +25,12 @@
 /* First, define some types. */
 
 struct cons_struct;
+struct symbol_struct;
 
 /* A value of some type */
 typedef struct {
   enum {
+    empty,			/* The empty list */
     integer,
     tfloat,
     string,
@@ -48,6 +50,7 @@
   union {
     void *ptr;			/* Pointer to the content */
     struct cons_struct *c;	/* ...or a pointer to a cons cell */
+    struct symbol_struct *sym;	/* ...or a pointer to a symbol */
     int i;			/* ...or an integer */
     float f;			/* ...or a floating point number */
   } content;			/* Stores a pointer or an integer */
@@ -65,7 +68,7 @@
 typedef struct cons_struct {	/* A pair of two values */
   value *car;
   value *cdr;
-} cons;
+} pair;
 
 /* A symbol with a name and possible value */
 /* (These do not need reference counters, they are kept unique by
@@ -82,10 +85,7 @@
 /* An environment; gives access to the stack and a hash table of
    defined symbols */
 typedef struct {
-  stackitem *gc_ref;
-  int gc_limit, gc_count;
-
-  cons *head;			/* Head of the stack */
+  value *head;			/* Head of the stack */
   hashtbl symbols;		/* Hash table of all variable bindings */
   int err;			/* Error flag */
   char *in_string;		/* Input pending to be read */
@@ -93,6 +93,11 @@
 				   read from in_string */
   FILE *inputstream;		/* stdin or a file, most likely */
   int interactive;		/* print prompts, stack, etc */
+
+  /* Garbage Collector stuff*/
+  stackitem *gc_ref;		/* Stack of all allocated values */
+  int gc_limit;			/* Run GC when this much is allocated */
+  int gc_count;			/* Amount currently allocated */
 } environment;
 
 /* A type for pointers to external functions */
@@ -116,12 +121,12 @@
 void push_sym(environment*, const char*);
 extern void nl();
 extern void type(environment*);
-void print_h(cons*, int);
+void print_h(value*, int);
 extern void print_(environment*);
 extern void print(environment*);
 extern void princ_(environment*);
 extern void princ(environment*);
-void print_st(cons*, long);
+void print_st(value*, long);
 extern void printstack(environment*);
 extern void swap(environment*);
 extern void rot(environment*);
@@ -164,3 +169,4 @@
 extern void sx_3c3d(environment*);
 extern void sx_3e3d(environment*);
 extern void sx_646976(environment*);
+extern void then(environment*);