implement bytecode interpreter and compiler

include/wolflisp.h

@@ -14,6 +14,7 @@ typedef intptr_t I;
 typedef uintptr_t U;
 typedef char C;
 typedef uint8_t U8;
+typedef uint16_t U16;
 typedef uint32_t U32;
 typedef int32_t I32;
 typedef size_t Z;
@@ -26,7 +27,7 @@ typedef U O;
 #define NUM(x) (((O)((I)(x) << 1)) | (O)1)
 #define ORD(x) ((I)(x) >> 1)
 
-// Pair
+// Cons pair
 typedef struct Pa {
   O head, tail;
 } Pa;
@@ -48,11 +49,21 @@ typedef struct Cl {
   O args, body, env;
 } Cl;
 
+// Bytecode
+typedef struct Bc {
+  Z len;
+  U8 *data;
+  Z constant_count;
+  O *constants;
+} Bc;
+
 // Primitive
 typedef struct In In;
 typedef struct Pr {
   const char *name;
-  O (*fn)(In *, O, O);
+  O (*fn)(In *, O *, int, O);  // fn(interp, args_array, argc, env)
+  int min_args;  // Minimum number of arguments (-1 for no check)
+  int max_args;  // Maximum number of arguments (-1 for variadic)
 } Pr;
 
 // Symbol table
@@ -62,7 +73,7 @@ typedef struct St {
   Sy **data;
 } St;
 
-#define HEAP_BYTES (1024 * 1024)
+#define HEAP_BYTES (4 * 1024 * 1024)
 #define TYPE_MASK 7
 
 enum {
@@ -81,6 +92,7 @@ enum {
   TYPE_STR,
   TYPE_CLOS,
   TYPE_MAC,
+  TYPE_CODE,
   TYPE_FWD,
   TYPE__MAX,
 };
@@ -125,6 +137,14 @@ typedef struct Er {
   } stack;
 } Er;
 
+// Call frame
+typedef struct Fr {
+  U8 *ip;
+  O env;
+} Fr;
+
+#define VM_STACK_SIZE 4096
+
 // Interpreter context
 typedef struct In {
   Gc gc;
@@ -132,8 +152,64 @@ typedef struct In {
   O env;
   Er err;
   O t; // the T symbol
+  O stack[VM_STACK_SIZE];
+  O *sp;
 } In;
 
+// Opcodes
+enum {
+  OP_HALT,
+  OP_CONST,
+  OP_GET,
+  OP_SET,
+  OP_JUMP,
+  OP_JUMP_IF_NIL,
+  OP_CALL,
+  OP_RET,
+  OP_POP,
+  OP_CLOS,
+  OP_TAIL_CALL,
+  OP_BIND,
+  OP_BIND_REST,
+  OP_PEEK,
+  OP_GET_LOCAL,    // Get local variable from stack frame
+  OP_SET_LOCAL,    // Set local variable in stack frame
+  OP_RESERVE,      // Reserve space for local variables
+};
+
+// Local variable info
+typedef struct Lv {
+  O name;      // Symbol name
+  U16 index;   // Stack slot index
+  int captured; // Is this variable captured by a closure?
+} Lv;
+
+// Compiler context
+typedef struct Cm {
+  In *in;
+  U8 *code;
+  Z count;
+  Z capacity;
+  struct {
+    O *data;
+    Z count;
+    Z capacity;
+  } constants;
+  struct {
+    O quote;
+    O iff;
+    O fn;
+    O progn;
+    O def;
+  } specials;
+  struct {
+    Lv *data;
+    Z count;
+    Z capacity;
+  } locals;
+  int use_stack_locals; // Use stack-based locals instead of env
+} Cm;
+
 enum {
   TOK_EOF = 0,
   TOK_COMMENT = ';',
@@ -180,8 +256,6 @@ V gc_finalize(Gc *gc);
 
 void error_init(Er *err);
 void error_throw(In *in, const char *fmt, ...);
-void error_push_frame(In *in, const char *frame);
-void error_pop_frame(In *in);
 void error_print(In *in);
 
 // Initialize an interpreter context.
@@ -189,12 +263,6 @@ V interp_init(In *in);
 // Finalize an interpreter context.
 V interp_finalize(In *in);
 
-// Evaluate a list of values.
-O interp_eval_list(In *in, O list, O env);
-
-// Evaluate an expression.
-O interp_eval(In *in, O obj, O env);
-
 // Intern a string
 Sy *intern(St *tab, const char *str, Z len);
 
@@ -209,10 +277,15 @@ V print(O obj);
 V println(O obj);
 
 O symbol_make(In *in, const char *str);
-O prim_make(In *in, const char *name, O (*fn)(In *, O, O));
+O prim_make(In *in, const char *name, O (*fn)(In *, O *, int, O), int min_args, int max_args);
 
 O list_assoc(In *in, O key, O alist);
 O list_reverse(In *in, O list);
+O list_next(In *in, O *list);
+
+V compile(Cm *co, O expr, I toplevel);
+V disassemble(Cm *co);
+O vm_run(Cm *c);
 
 int nexttoken(Lx *lex);