Fix a compiler bug in the do special form.

src/compiler/boot.dst

@@ -305,8 +305,8 @@ If no match is found, returns nil"
 
 # Start pretty printer
 (def pp (do
-  (defn- pp-seq [pp seen buf a start end]
-   (if (get seen a)
+  (defn- pp-seq [pp seen buf a start end checkcycle]
+   (if (and checkcycle (get seen a))
     (buffer-push-string buf "<cycle>")
     (do
      (put seen a true)
@@ -318,8 +318,8 @@ If no match is found, returns nil"
      (buffer-push-string buf end)))
    buf)
 
-  (defn- pp-dict [pp seen buf a start end]
-   (if (get seen a)
+  (defn- pp-dict [pp seen buf a start end checkcycle]
+   (if (and checkcycle (get seen a))
     (buffer-push-string buf "<cycle>")
     (do
      (put seen a true)
@@ -336,9 +336,9 @@ If no match is found, returns nil"
    buf)
 
   (def printers :private {
-   :array  (fn [pp seen buf x] (pp-seq pp seen buf x "[" "]"))
+   :array  (fn [pp seen buf x] (pp-seq pp seen buf x "[" "]" true))
    :tuple  (fn [pp seen buf x] (pp-seq pp seen buf x "(" ")"))
-   :table  (fn [pp seen buf x] (pp-dict pp seen buf x "@{" "}"))
+   :table  (fn [pp seen buf x] (pp-dict pp seen buf x "@{" "}" true))
    :struct (fn [pp seen buf x] (pp-dict pp seen buf x "{" "}"))
   })
 

src/compiler/specials.c

@@ -352,9 +352,9 @@ DstSlot dstc_if(DstFopts opts, DstAst *ast, int32_t argn, const Dst *argv) {
     }
 
     /* Set target for compilation */
-    target = (!drop && !tail) 
-        ? dstc_gettarget(opts)
-        : dstc_cslot(dst_wrap_nil());
+    target = (drop || tail) 
+        ? dstc_cslot(dst_wrap_nil())
+        : dstc_gettarget(opts);
 
     /* Compile jump to right */
     condlocal = dstc_preread(c, ast, 0xFF, 1, cond);
@@ -393,7 +393,7 @@ DstSlot dstc_if(DstFopts opts, DstAst *ast, int32_t argn, const Dst *argv) {
  * evaluate to the last expression in the body. */
 DstSlot dstc_do(DstFopts opts, DstAst *ast, int32_t argn, const Dst *argv) {
     int32_t i;
-    DstSlot ret;
+    DstSlot ret = dstc_cslot(dst_wrap_nil());
     DstCompiler *c = opts.compiler;
     DstFopts subopts = dstc_fopts_default(c);
     (void) ast;
@@ -401,8 +401,8 @@ DstSlot dstc_do(DstFopts opts, DstAst *ast, int32_t argn, const Dst *argv) {
     for (i = 0; i < argn; i++) {
         if (i != argn - 1) {
             subopts.flags = DST_FOPTS_DROP;
-        } else if (opts.flags & DST_FOPTS_TAIL) {
-            subopts.flags = DST_FOPTS_TAIL;
+        } else {
+            subopts = opts;
         }
         ret = dstc_value(subopts, argv[i]);
         if (i != argn - 1) {

src/core/struct.c

@@ -31,7 +31,7 @@ DstKV *dst_struct_begin(int32_t count) {
 
     /* Calculate capacity as power of 2 after 2 * count. */
     int32_t capacity = dst_tablen(2 * count);
-    if (capacity < 0) capacity = dst_tablen(count);
+    if (capacity < 0) capacity = dst_tablen(count + 1);
 
     size_t s = sizeof(int32_t) * 4 + (capacity * sizeof(DstKV));
     char *data = dst_gcalloc(DST_MEMORY_STRUCT, s);
@@ -40,6 +40,7 @@ DstKV *dst_struct_begin(int32_t count) {
     dst_struct_length(st) = count;
     dst_struct_capacity(st) = capacity;
     dst_struct_hash(st) = 0;
+    (dst_struct_raw(st)[3]) = 0;
     return st;
 }
 
@@ -155,7 +156,7 @@ const DstKV *dst_struct_end(DstKV *st) {
 /* Get an item from a struct */
 Dst dst_struct_get(const DstKV *st, Dst key) {
     const DstKV *kv = dst_struct_find(st, key);
-    if (NULL == kv || dst_checktype(kv->key, DST_NIL)) {
+    if (NULL == kv) {
         return dst_wrap_nil();
     } else {
         return kv->value;

src/core/symcache.c

@@ -216,7 +216,7 @@ static void inc_counter(uint8_t *digits, int base, int len) {
 }
 
 /* Generate a unique symbol. This is used in the library function gensym. The
- * symbol will be of the format prefix--XXXXXX, where X is a base64 digit, and
+ * symbol will be of the format prefix_XXXXXX, where X is a base64 digit, and
  * prefix is the argument passed.  */
 const uint8_t *dst_symbol_gen(const uint8_t *buf, int32_t len) {
     const uint8_t **bucket = NULL;
@@ -224,15 +224,14 @@ const uint8_t *dst_symbol_gen(const uint8_t *buf, int32_t len) {
     uint8_t counter[6] = {63, 63, 63, 63, 63, 63};
     /* Leave spaces for 6 base 64 digits and two dashes. That means 64^6 possible suffixes, which
      * is enough for resolving collisions. */
-    int32_t newlen = len + 8;
+    int32_t newlen = len + 7;
     int32_t newbufsize = newlen + 2 * sizeof(int32_t) + 1;
     uint8_t *str = (uint8_t *)dst_gcalloc(DST_MEMORY_SYMBOL, newbufsize) + 2 * sizeof(int32_t);
     dst_string_length(str) = newlen;
     memcpy(str, buf, len);
-    str[len] = '-';
-    str[len + 1] = '-';
+    str[len] = '_';
     str[newlen] = 0;
-    uint8_t *saltbuf = str + len + 2;
+    uint8_t *saltbuf = str + len + 1;
     int status = 1;
     while (status) {
         int i;