proper lexical scoping now woo

.editorconfig

@@ -4,7 +4,7 @@ root = true
 end_of_line = lf
 insert_final_newline = true
 
-[*.{c,h}]
+[*.{c,h,scm}]
 indent_style = space
 indent_size = 2
 

examples/fizzbuzz.scm

@@ -0,0 +1,22 @@
+(def each-integer-aux
+  (fn (n i thunk)
+    (if (= n 0)
+        '()
+        (progn
+          (thunk (- (+ i 1) n))
+          (each-integer-aux (- n 1) i thunk)))))
+
+(def each-integer
+  (fn (n thunk)
+    (each-integer-aux n n thunk)))
+
+(each-integer 30
+  (fn (x)
+    (if (or (= 0 (% x 3)) (= 0 (% x 5)))
+      (progn
+        (if (= 0 (% x 3))
+          (write "Fizz"))
+        (if (= 0 (% x 5))
+          (write "Buzz")))
+      (print x))
+    (write "\n")))

examples/map.scm

@@ -0,0 +1,19 @@
+(def defn
+  (mac (name args . body)
+    (list 'def name (cons 'fn (cons args body)))))
+
+(defn map-aux (f acc l)
+  (if (nil? l)
+    (acc f '())
+    (map-aux
+      f
+      (fn (f ys)
+        (acc f (cons (f (head l)) ys)))
+      (tail l))))
+
+(defn map (f l)
+  (map-aux f (fn (f x) x) l))
+
+(println
+  (map (fn (x) (* x x))
+       '(1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20)))

include/wolflisp.h

@@ -176,16 +176,20 @@ enum {
   OP_GET_LOCAL,
   OP_SET_LOCAL,
   OP_RESERVE,
+  OP_DUP,
 };
 
 // Local variable info
 typedef struct Lv {
   O name;
   U16 index;
+  I escapes;
 } Lv;
 
 // Compiler context
-typedef struct Cm {
+typedef struct Cm Cm;
+struct Cm {
+  Cm *parent;
   In *in;
   U8 *code;
   Z count;
@@ -202,6 +206,8 @@ typedef struct Cm {
     O mac;
     O progn;
     O def;
+    O and;
+    O or;
   } specials;
   struct {
     Lv *data;
@@ -209,7 +215,7 @@ typedef struct Cm {
     Z capacity;
   } locals;
   I use_locals;
-} Cm;
+};
 
 enum {
   TOK_EOF = 0,

src/core/compile.c

@@ -25,6 +25,17 @@ static void add_local(Cm *co, O sym) {
   co->locals.count++;
 }
 
+static void mark_escaping(Cm *co, O sym) {
+  for (Z i = 0; i < co->locals.count; i++) {
+    if (co->locals.data[i].name == sym) {
+      co->locals.data[i].escapes = 1;
+      return;
+    }
+  }
+}
+
+static I is_local(Cm *co, O sym) { return find_local(co, sym) >= 0; }
+
 static V emit(Cm *co, U8 byte) {
   if (co->count >= co->capacity) {
     Z newcap = co->capacity == 0 ? 16 : co->capacity * 2;
@@ -162,18 +173,88 @@ static V compile_progn(Cm *co, O forms, I tail) {
   }
 }
 
-static int nested_p(Cm *c, O body) {
-  while (body != NIL) {
-    O expr = list_next(c->in, &body);
-    if (type(expr) == TYPE_PAIR) {
-      Pa *p = pair_unwrap(c->in, expr);
-      if (p->head == c->specials.fn)
-        return 1;
-      if (nested_p(c, expr))
-        return 1;
+// Find all free variables in an expression (vars used but not defined locally)
+static void find_free_vars(Cm *co, O expr, Cm *parent) {
+  I ty = type(expr);
+  switch (ty) {
+  case TYPE_SYM:
+    // If this symbol isn't local to current function but is in parent scope
+    if (!is_local(co, expr) && parent && is_local(parent, expr)) {
+      // Mark it as escaping in the parent
+      mark_escaping(parent, expr);
     }
+    break;
+  case TYPE_PAIR: {
+    Pa *p = pair_unwrap(co->in, expr);
+    O head = p->head;
+
+    // Skip quote - quoted expressions aren't variable references
+    if (type(head) == TYPE_SYM && head == co->specials.quote) {
+      return;
+    }
+
+    // Handle nested fn/mac - need to analyze their bodies for free variables
+    if (type(head) == TYPE_SYM &&
+        (head == co->specials.fn || head == co->specials.mac)) {
+      // This is a nested function definition
+      // Parse it to find what variables it captures
+      Pa *fn_tail = pair_unwrap(co->in, p->tail);
+      O nested_args = fn_tail->head;
+      O nested_body = fn_tail->tail;
+
+      // Create a temporary compiler for the nested function
+      Cm nested;
+      memset(&nested, 0, sizeof(Cm));
+      nested.in = co->in;
+      nested.specials = co->specials;
+      nested.parent = co;
+
+      // Add nested function's parameters as locals
+      O curr_arg = nested_args;
+      while (curr_arg != NIL) {
+        if (type(curr_arg) == TYPE_SYM) {
+          add_local(&nested, curr_arg);
+          break;
+        }
+        Pa *arg_pair = pair_unwrap(co->in, curr_arg);
+        add_local(&nested, arg_pair->head);
+        curr_arg = arg_pair->tail;
+      }
+
+      // Analyze the nested function's body to find free variables
+      O body_copy = nested_body;
+      while (body_copy != NIL) {
+        if (type(body_copy) != TYPE_PAIR) {
+          find_free_vars(&nested, body_copy, co);
+          break;
+        }
+        Pa *body_pair = pair_unwrap(co->in, body_copy);
+        find_free_vars(&nested, body_pair->head, co);
+        body_copy = body_pair->tail;
+      }
+
+      // Free the temporary compiler
+      if (nested.locals.data)
+        free(nested.locals.data);
+
+      return;
+    }
+
+    // For other expressions, recurse into all subexpressions
+    O curr = expr;
+    while (curr != NIL) {
+      if (type(curr) != TYPE_PAIR) {
+        break;
+      }
+      Pa *pair = pair_unwrap(co->in, curr);
+      find_free_vars(co, pair->head, parent);
+      curr = pair->tail;
+    }
+    break;
+  }
+  default:
+    break;
   }
-  return 0;
 }
 
 // Compile a closure with `args` and `body`.
@@ -183,13 +264,14 @@ static V compile_fn(Cm *c, O args, O body, I macro) {
   memset(&ic, 0, sizeof(Cm));
   ic.in = c->in;
   ic.specials = c->specials;
+  ic.parent = c; // Link to parent scope
 
   O curr = args;
   O fixed[256];
   int fixed_count = 0;
   O rest = NIL;
 
-  // Count fixed arguments, and if the function has a rest argument
+  // Count fixed arguments
   while (curr != NIL) {
     if (type(curr) == TYPE_SYM) {
       rest = curr;
@@ -200,18 +282,46 @@ static V compile_fn(Cm *c, O args, O body, I macro) {
     curr = p->tail;
   }
 
-  int nested = nested_p(c, body);
-  if (rest == NIL && !nested) {
-    // If the function has no rest argument, and has no nested closures inside
-    // it, compile using stack locals as an optimization for tail-calls
-    ic.use_locals = 1;
-    curr = args;
-    for (O next = list_next(c->in, &curr); next != NIL;
-         next = list_next(c->in, &curr))
-      add_local(&ic, next);
-  } else {
-    // Otherwise, fallback to using environment bindings for locals
+  // Add parameters as locals to inner compiler
+  curr = args;
+  while (curr != NIL) {
+    if (type(curr) == TYPE_SYM) {
+      add_local(&ic, curr);
+      break;
+    }
+    Pa *p = pair_unwrap(c->in, curr);
+    add_local(&ic, p->head);
+    curr = p->tail;
+  }
+
+  // Analyze body to find free variables and mark them as escaping in parent
+  O body_copy = body;
+  while (body_copy != NIL) {
+    O expr = list_next(c->in, &body_copy);
+    find_free_vars(&ic, expr, c);
+  }
+
+  // Decide whether to use stack locals or environment bindings
+  // Use stack locals only if:
+  // 1. No rest parameter (rest parameters require environment bindings)
+  // 2. None of our own locals escape (are captured by nested functions)
+  ic.use_locals = 1;
+
+  // If we have a rest parameter, we must use environment bindings
+  if (rest != NIL)
     ic.use_locals = 0;
+
+  // Check if any of this function's locals escape (are captured by nested
+  // functions) find_free_vars has already marked escaping variables in
+  // ic.locals
+  for (Z i = 0; i < ic.locals.count; i++) {
+    if (ic.locals.data[i].escapes) {
+      ic.use_locals = 0;
+      break;
+    }
+  }
+  // If we need environment bindings, emit BIND instructions
+  if (!ic.use_locals) {
     if (rest != NIL) {
       emit(&ic, OP_BIND_REST);
       emit16(&ic, add_constant(&ic, rest));
@@ -223,24 +333,123 @@ static V compile_fn(Cm *c, O args, O body, I macro) {
     }
   }
 
-  // Compile the function's body (as a `progn` form)
+  // Compile the function's body
   compile_progn(&ic, body, 1);
+
   O code = code_make(c->in, ic.code, ic.count, ic.constants.data,
                      ic.constants.count);
   Z code_idx = add_constant(c, code);
   Z args_idx = add_constant(c, args);
 
-  // Compile pushing the closure to the stack.
+  // Compile pushing the closure to the stack
   emit(c, macro ? OP_MAC : OP_CLOS);
   emit16(c, code_idx);
   emit16(c, args_idx);
 
-  // Free the inner compiler context.
+  // Free the inner compiler context
   free(ic.code);
   if (ic.locals.data)
     free(ic.locals.data);
 }
 
+// Compile the `(and ...)` special form
+static V compile_and(Cm *co, O forms, I tail) {
+  if (forms == NIL) {
+    emit(co, OP_CONST);
+    emit16(co, add_constant(co, co->in->t));
+    if (tail)
+      emit(co, OP_RET);
+    return;
+  }
+
+  Z *jumps = NULL;
+  Z jump_count = 0;
+  Z jump_cap = 0;
+
+  while (forms != NIL) {
+    O expr = list_next(co->in, &forms);
+    if (forms == NIL) {
+      compile(co, expr, tail);
+    } else {
+      compile(co, expr, 0);
+      emit(co, OP_DUP);
+      emit(co, OP_JUMP_IF_NIL);
+      if (jump_count >= jump_cap) {
+        jump_cap = jump_cap == 0 ? 8 : jump_cap * 2;
+        jumps = realloc(jumps, jump_cap * sizeof(Z));
+      }
+      jumps[jump_count++] = co->count;
+      emit16(co, 0);
+      emit(co, OP_POP);
+    }
+  }
+
+  Z end = co->count;
+  for (Z i = 0; i < jump_count; i++) {
+    Z j = jumps[i];
+    co->code[j] = (U8)(end >> 8);
+    co->code[j + 1] = (U8)(end & 0xff);
+  }
+  if (jumps)
+    free(jumps);
+
+  if (tail)
+    emit(co, OP_RET);
+}
+
+// Compile the `(or ...)` special form
+static V compile_or(Cm *co, O forms, I tail) {
+  if (forms == NIL) {
+    emit(co, OP_CONST);
+    emit16(co, add_constant(co, NIL));
+    if (tail)
+      emit(co, OP_RET);
+    return;
+  }
+
+  Z *jumps = NULL;
+  Z jump_count = 0;
+  Z jump_cap = 0;
+
+  while (forms != NIL) {
+    O expr = list_next(co->in, &forms);
+    if (forms == NIL) {
+      compile(co, expr, tail);
+    } else {
+      compile(co, expr, 0);
+      emit(co, OP_DUP);
+      emit(co, OP_JUMP_IF_NIL);
+      Z jump_next = co->count;
+      emit16(co, 0);
+
+      emit(co, OP_JUMP);
+      if (jump_count >= jump_cap) {
+        jump_cap = jump_cap == 0 ? 8 : jump_cap * 2;
+        jumps = realloc(jumps, jump_cap * sizeof(Z));
+      }
+      jumps[jump_count++] = co->count;
+      emit16(co, 0);
+
+      Z next = co->count;
+      co->code[jump_next] = (U8)(next >> 8);
+      co->code[jump_next + 1] = (U8)(next & 0xff);
+      emit(co, OP_POP);
+    }
+  }
+
+  Z end = co->count;
+  for (Z i = 0; i < jump_count; i++) {
+    Z j = jumps[i];
+    co->code[j] = (U8)(end >> 8);
+    co->code[j + 1] = (U8)(end & 0xff);
+  }
+  if (jumps)
+    free(jumps);
+
+  if (tail)
+    emit(co, OP_RET);
+}
+
 // Compile the `(def name value)` special form
 static V compile_def(Cm *c, O args, I tail) {
   O sym = list_next(c->in, &args);
@@ -290,6 +499,12 @@ static V compile_apply(Cm *co, O expr, I tail) {
       if (tail)
         emit(co, OP_RET);
       return;
+    } else if (head == co->specials.and) {
+      compile_and(co, p->tail, tail);
+      return;
+    } else if (head == co->specials.or) {
+      compile_or(co, p->tail, tail);
+      return;
     } else if (head == co->specials.def) {
       compile_def(co, p->tail, tail);
       return;
@@ -324,6 +539,10 @@ V compile(Cm *co, O expr, I tail) {
     co->specials.def = symbol_make(co->in, "def");
   if (co->specials.mac == NIL)
     co->specials.mac = symbol_make(co->in, "mac");
+  if (co->specials.and == NIL)
+    co->specials.and = symbol_make(co->in, "and");
+  if (co->specials.or == NIL)
+    co->specials.or = symbol_make(co->in, "or");
 
   switch (ty) {
   case TYPE_NIL:
@@ -338,11 +557,13 @@ V compile(Cm *co, O expr, I tail) {
     if (co->use_locals) {
       int idx = find_local(co, expr);
       if (idx >= 0) {
-        emit(co, OP_GET_LOCAL);
-        emit16(co, idx);
-        if (tail)
-          emit(co, OP_RET);
-        return;
+        if (!co->locals.data[idx].escapes) {
+          emit(co, OP_GET_LOCAL);
+          emit16(co, idx);
+          if (tail)
+            emit(co, OP_RET);
+          return;
+        }
       }
     }
     emit(co, OP_GET);

src/core/disasm.c

@@ -109,6 +109,9 @@ V disassemble(Cm *co) {
       ofs += 2;
       break;
     }
+    case OP_DUP:
+      printf("DUP\n");
+      break;
     default:
       printf("%02x\n", co->code[ofs]);
     }

src/core/interp.c

@@ -31,10 +31,13 @@ V interp_init(In *in) {
   PRIM("print", prim_print, 1, 1);
   PRIM("println", prim_println, 1, 1);
   PRIM("write", prim_write, 1, 1);
+  PRIM("env", prim_env, 0, 0);
+  PRIM("nil?", prim_nil_p, 1, 1);
   PRIM("+", prim_add, 0, -1);  // variadic
   PRIM("-", prim_sub, 0, -1);  // variadic
   PRIM("*", prim_mul, 0, -1);  // variadic
   PRIM("/", prim_div, 0, -1);  // variadic
+  PRIM("%", prim_mod, 0, -1);  // variadic
   PRIM("<", prim_lt, 2, 2);
   PRIM(">", prim_gt, 2, 2);
   PRIM("=", prim_equal, 0, -1);  // variadic

src/core/prim.c

@@ -70,7 +70,8 @@ O prim_write(In *in, O *args, int argc, O env) {
   if (argc != 1)
     error_throw(in, "write: expected 1 argument, got %d", argc);
   if (type(args[0]) != TYPE_STR)
-    error_throw(in, "write: expected string argument, got %s", typename(type(args[0])));
+    error_throw(in, "write: expected string argument, got %s",
+                typename(type(args[0])));
   Ss *s = (Ss *)(UNBOX(args[0]) + 1);
   printf("%.*s", (int)s->len, s->data);
   return NIL;
@@ -132,6 +133,23 @@ O prim_div(In *in, O *args, int argc, O env) {
   return NUM(result);
 }
 
+O prim_mod(In *in, O *args, int argc, O env) {
+  (void)env;
+  if (argc == 0)
+    return NUM(1);
+  if (!IMM(args[0]))
+    error_throw(in, "/: non numeric argument at position 0");
+  I result = ORD(args[0]);
+  for (int i = 1; i < argc; i++) {
+    if (!IMM(args[i]))
+      error_throw(in, "/: non numeric argument at position %d", i);
+    if (ORD(args[i]) == 0)
+      error_throw(in, "/: division by zero at position %d", i);
+    result %= ORD(args[i]);
+  }
+  return NUM(result);
+}
+
 O prim_equal(In *in, O *args, int argc, O env) {
   (void)env;
   if (argc < 2)
@@ -168,6 +186,20 @@ O prim_gt(In *in, O *args, int argc, O env) {
   }
 }
 
+O prim_nil_p(In *in, O *args, int argc, O env) {
+  (void)env;
+  if (argc != 1)
+    error_throw(in, "nil?: expected 1 argument, got %d", argc);
+  return BOOL(args[0] == NIL);
+}
+
+O prim_env(In *in, O *args, int argc, O env) {
+  (void)args;
+  (void)argc;
+  (void)env;
+  return in->env;
+}
+
 O prim_gc(In *in, O *args, int argc, O env) {
   (void)args;
   (void)argc;

src/core/prim.h

@@ -11,7 +11,10 @@ O prim_add(In *in, O *args, int argc, O env);
 O prim_sub(In *in, O *args, int argc, O env);
 O prim_mul(In *in, O *args, int argc, O env);
 O prim_div(In *in, O *args, int argc, O env);
+O prim_mod(In *in, O *args, int argc, O env);
 O prim_equal(In *in, O *args, int argc, O env);
 O prim_lt(In *in, O *args, int argc, O env);
 O prim_gt(In *in, O *args, int argc, O env);
+O prim_nil_p(In *in, O *args, int argc, O env);
+O prim_env(In *in, O *args, int argc, O env);
 O prim_gc(In *in, O *args, int argc, O env);

src/core/symbol.c

@@ -15,9 +15,7 @@ static Sy *find(St *tab, const char *str, U32 hash, Z len) {
     Sy *s = tab->data[ix];
     if (!s)
       return NULL;
-    if (s->hash == hash && s->len == len)
-      return s;
-    if (memcmp(s->data, str, len) == 0)
+    if (s->hash == hash && s->len == len && memcmp(s->data, str, len) == 0)
       return s;
     ix = (ix + 1) % tab->capacity;
   }

src/core/vm.c

@@ -228,6 +228,11 @@ static O vm_exec(Cm *co_in, O env_in, int argc_in) {
       PUSH(BOX(hdr));
       break;
     }
+    case OP_DUP: {
+      O val = PEEK();
+      PUSH(val);
+      break;
+    }
     default:
       error_throw(in, "unknown opcode %d", op);
     }

test_macro.lisp

@@ -1,8 +0,0 @@
-(def twice (mac (x)
-  (list 'progn x x)))
-
-(def when (mac (cond . body)
-  (list 'if cond (cons 'progn body))))
-
-(when (= 1 1)
-  (twice (write "ok\n")))