Initial hugenums implementation (incomplete).hugenums

8 files changed, 518 insertions, 105 deletions

diff --git a/bignum.c b/bignum.c
index 8c5d298d..38919eb5 100644
--- a/bignum.c
+++ b/bignum.c
@@ -233,13 +233,13 @@ sexp sexp_read_bignum (sexp ctx, sexp in, sexp_uint_t init,
       res = sexp_read_error(ctx, "found non-base 10 float", SEXP_NULL, in);
     } else {
       if (c!='.') sexp_push_char(ctx, c, in); /* push the e back */
-      res = sexp_read_float_tail(ctx, in, sexp_bignum_to_double(res), (sign==-1));
+      res = sexp_read_float_tail(ctx, in, sexp_bignum_to_double(res), (sign==-1), 0);
     }
 #if SEXP_USE_RATIOS
   } else if (c=='/') {
     res = sexp_bignum_normalize(res);
     res = sexp_make_ratio(ctx, res, SEXP_ONE);
-    sexp_ratio_denominator(res) = sexp_read_number(ctx, in, 10);
+    sexp_ratio_denominator(res) = sexp_read_number(ctx, in, 10, 1);
     res = sexp_ratio_normalize(ctx, res, in);
 #endif
 #if SEXP_USE_COMPLEX
@@ -839,6 +839,109 @@ sexp sexp_complex_atan (sexp ctx, sexp z) {
 #endif
 #endif
 
+#if SEXP_USE_HUGENUMS
+
+/* Conway's chained arrows */
+
+/* Here a, b, c are integers, and X, Y are arbitrary subchains. */
+
+/* 1. a = a                                              */
+/* 2. a->b = a^b                                         */
+/* 3. X->1->... = X                                      */
+/* 4. X->(a+1)->(b+1) = X->(X->a->(b+1))->b              */
+
+/* Alternate forms */
+
+/* a->b->c = hyper(a, c+2, b)  in hyper notation         */
+/*         = a^^...^^b         in Knuth's arrow notation */
+/*             c '^'s                                    */
+
+/* Ackermann(a, b) = (2->(a+3)->(b-2)) - 3  for b > 2*/
+
+/* Special cases */
+
+/* 2->2->X = 4        (will always expand to a power tower of 2 2s) */
+/* X->2->2 = X->(X)   (chain X with it's value concatenated to it) */
+/* a->b->2 = a^^b     (a tetrated to b) */
+/* a->2->3 = a->a->2  (a tetrated to itself) */
+/* a->3->3 = a->(a->a->2)->2 = a^^(a^^a) */
+/* a->b->c->d = huge for a, b, c, d >= 2, a or b >= 3 */
+
+sexp sexp_make_hugenum (sexp ctx, sexp_uint_t len) {
+  sexp_uint_t size = sexp_sizeof(hugenum) + len*sizeof(sexp);
+  sexp res = sexp_alloc_tagged(ctx, size, SEXP_HUGENUM);
+  sexp_hugenum_length(res) = len;
+  return res;
+}
+
+sexp sexp_copy_hugenum (sexp ctx, sexp a) {
+  sexp_uint_t i, len = sexp_hugenum_length(a);
+  sexp_uint_t size = sexp_sizeof(hugenum) + len*sizeof(sexp);
+  sexp res = sexp_alloc_tagged(ctx, size, SEXP_HUGENUM);
+  sexp_hugenum_length(res) = len;
+  for (i=0; i<len; i++) sexp_hugenum_data(res)[i] = sexp_hugenum_data(a)[i];
+  return res;
+}
+
+sexp sexp_hugenum2 (sexp ctx, sexp base, sexp exponent) {
+  sexp res = sexp_make_hugenum(ctx, 2);
+  sexp_hugenum_data(res)[0] = base;
+  sexp_hugenum_data(res)[1] = exponent;
+  return res;
+}
+
+int sexp_hugenum_sign (sexp a) {
+  sexp first = sexp_hugenum_data(a)[0];
+  if (sexp_fixnump(first))
+    return sexp_unbox_fixnum(first);
+  if (sexp_bignump(first))
+    return sexp_bignum_sign(first);
+  return 0;  /* shouldn't happen */
+}
+
+int sexp_compare_hugenum_magnitude (sexp ctx, sexp a, sexp b, int sign) {
+  sexp *av, *bv;
+  int i, diff;
+  sexp_gc_var2(loga, logb);
+  if ((diff = sexp_hugenum_length(a) - sexp_hugenum_length(b)) != 0)
+    return diff * sign;
+  if (sexp_hugenum_length(a) == 2) {
+    sexp_gc_preserve2(ctx, loga, logb);
+    loga = sexp_log(ctx, a);
+    logb = sexp_log(ctx, b);
+    diff = sexp_unbox_fixnum(sexp_compare(ctx, loga, logb));
+    sexp_gc_release2(ctx);
+    return diff;
+  }
+  av = sexp_hugenum_data(a);
+  bv = sexp_hugenum_data(b);
+  for (i=sexp_hugenum_length(a); i>=0; i--)
+    if ((diff = sexp_unbox_fixnum(sexp_compare(ctx, av[i], bv[i]))) != 0)
+      return diff * sign;
+  return 0;
+}
+
+int sexp_compare_hugenum (sexp ctx, sexp a, sexp b) {
+  int sign;
+  if ((sign = sexp_hugenum_sign(a)) != sexp_hugenum_sign(b))
+    return sign;
+  return sexp_compare_hugenum_magnitude(ctx, a, b, sign);
+}
+
+sexp sexp_max_hugenum_magnitude (sexp ctx, sexp a, sexp b) {
+  if (sexp_compare_hugenum_magnitude(ctx, a, b, 1) < 0)
+    return b;
+  return a;
+}
+
+sexp sexp_max_hugenum (sexp ctx, sexp a, sexp b) {
+  if (sexp_compare_hugenum(ctx, a, b) < 0)
+    return b;
+  return a;
+}
+
+#endif
+
 /****************** generic arithmetic ************************/
 
 enum sexp_number_types {
@@ -852,6 +955,9 @@ enum sexp_number_types {
 #if SEXP_USE_COMPLEX
   SEXP_NUM_CPX,
 #endif
+#if SEXP_USE_HUGENUMS
+  SEXP_NUM_HUG,
+#endif
 };
 
 enum sexp_number_combs {
@@ -865,6 +971,9 @@ enum sexp_number_combs {
 #if SEXP_USE_COMPLEX
   SEXP_NUM_NOT_CPX,
 #endif
+#if SEXP_USE_HUGENUMS
+  SEXP_NUM_NOT_HUG,
+#endif
   SEXP_NUM_FIX_NOT,
   SEXP_NUM_FIX_FIX,
   SEXP_NUM_FIX_FLO,
@@ -875,6 +984,9 @@ enum sexp_number_combs {
 #if SEXP_USE_COMPLEX
   SEXP_NUM_FIX_CPX,
 #endif
+#if SEXP_USE_HUGENUMS
+  SEXP_NUM_FIX_HUG,
+#endif
   SEXP_NUM_FLO_NOT,
   SEXP_NUM_FLO_FIX,
   SEXP_NUM_FLO_FLO,
@@ -885,6 +997,9 @@ enum sexp_number_combs {
 #if SEXP_USE_COMPLEX
   SEXP_NUM_FLO_CPX,
 #endif
+#if SEXP_USE_HUGENUMS
+  SEXP_NUM_FLO_HUG,
+#endif
   SEXP_NUM_BIG_NOT,
   SEXP_NUM_BIG_FIX,
   SEXP_NUM_BIG_FLO,
@@ -895,6 +1010,9 @@ enum sexp_number_combs {
 #if SEXP_USE_COMPLEX
   SEXP_NUM_BIG_CPX,
 #endif
+#if SEXP_USE_HUGENUMS
+  SEXP_NUM_BIG_HUG,
+#endif
 #if SEXP_USE_RATIOS
   SEXP_NUM_RAT_NOT,
   SEXP_NUM_RAT_FIX,
@@ -904,6 +1022,9 @@ enum sexp_number_combs {
 #if SEXP_USE_COMPLEX
   SEXP_NUM_RAT_CPX,
 #endif
+#if SEXP_USE_HUGENUMS
+  SEXP_NUM_RAT_HUG,
+#endif
 #endif
 #if SEXP_USE_COMPLEX
   SEXP_NUM_CPX_NOT,
@@ -914,11 +1035,28 @@ enum sexp_number_combs {
   SEXP_NUM_CPX_RAT,
 #endif
   SEXP_NUM_CPX_CPX,
+#if SEXP_USE_HUGENUMS
+  SEXP_NUM_CPX_HUG,
+#endif
+#endif
+#if SEXP_USE_COMPLEX
+  SEXP_NUM_HUG_NOT,
+  SEXP_NUM_HUG_FIX,
+  SEXP_NUM_HUG_FLO,
+  SEXP_NUM_HUG_BIG,
+  SEXP_NUM_HUG_RAT,
+#if SEXP_USE_HUGENUMS
+  SEXP_NUM_HUG_CPX,
+#endif
+  SEXP_NUM_HUG_HUG,
 #endif
 };
 
 static int sexp_number_types[] =
-#if SEXP_USE_RATIOS && SEXP_USE_COMPLEX
+#if SEXP_USE_HUGENUMS && SEXP_USE_COMPLEX
+  {0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 2, 3, 4, 5, 6, 0};
+#else
+#if SEXP_USE_RATIOS && (SEXP_USE_COMPLEX || SEXP_USE_HUGENUMS)
   {0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 2, 3, 4, 5, 0, 0};
 #else
 #if SEXP_USE_RATIOS || SEXP_USE_COMPLEX
@@ -927,8 +1065,9 @@ static int sexp_number_types[] =
   {0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 2, 3, 0, 0, 0, 0};
 #endif
 #endif
+#endif
 
-#define SEXP_NUM_NUMBER_TYPES (4 + SEXP_USE_RATIOS + SEXP_USE_COMPLEX)
+#define SEXP_NUM_NUMBER_TYPES (4 + SEXP_USE_RATIOS + SEXP_USE_COMPLEX + SEXP_USE_HUGENUMS)
 
 static int sexp_number_type (sexp a) {
   return sexp_pointerp(a) ?
@@ -940,6 +1079,16 @@ static int sexp_number_type (sexp a) {
     : sexp_fixnump(a);
 }
 
+#if SEXP_USE_RATIOS
+#define sexp_rat_case(x) case x:
+#endif
+#if SEXP_USE_COMPLEX
+#define sexp_cpx_case(x) case x:
+#endif
+#if SEXP_USE_HUGENUMS
+#define sexp_hug_case(x) case x:
+#endif
+
 sexp sexp_add (sexp ctx, sexp a, sexp b) {
   sexp_sint_t sum;
   int at=sexp_number_type(a), bt=sexp_number_type(b), t;
@@ -950,12 +1099,9 @@ sexp sexp_add (sexp ctx, sexp a, sexp b) {
   switch ((at * SEXP_NUM_NUMBER_TYPES) + bt) {
   case SEXP_NUM_NOT_NOT: case SEXP_NUM_NOT_FIX:
   case SEXP_NUM_NOT_FLO: case SEXP_NUM_NOT_BIG:
-#if SEXP_USE_RATIOS
-  case SEXP_NUM_NOT_RAT:
-#endif
-#if SEXP_USE_COMPLEX
-  case SEXP_NUM_NOT_CPX:
-#endif
+  sexp_rat_case(SEXP_NUM_NOT_RAT)
+  sexp_cpx_case(SEXP_NUM_NOT_CPX)
+  sexp_hug_case(SEXP_NUM_NOT_HUG)
     r = sexp_type_exception(ctx, NULL, SEXP_NUMBER, a);
     break;
   case SEXP_NUM_FIX_FIX:
@@ -993,9 +1139,7 @@ sexp sexp_add (sexp ctx, sexp a, sexp b) {
     break;
 #endif
 #if SEXP_USE_COMPLEX
-#if SEXP_USE_RATIOS
-  case SEXP_NUM_RAT_CPX:
-#endif
+  sexp_rat_case(SEXP_NUM_RAT_CPX)
   case SEXP_NUM_FLO_CPX:
   case SEXP_NUM_FIX_CPX:
   case SEXP_NUM_BIG_CPX:
@@ -1005,6 +1149,23 @@ sexp sexp_add (sexp ctx, sexp a, sexp b) {
     r = sexp_complex_add(ctx, a, b);
     break;
 #endif
+#if SEXP_USE_HUGENUMS
+  case SEXP_NUM_FLO_HUG:
+    r = sexp_infp(a) ? a : b;
+    break;
+  case SEXP_NUM_RAT_HUG:
+  case SEXP_NUM_FIX_HUG:
+  case SEXP_NUM_BIG_HUG:
+    r = b;
+    break;
+  case SEXP_NUM_CPX_HUG:
+    b = tmp = sexp_make_complex(ctx, b, SEXP_ZERO);
+    r = sexp_complex_add(ctx, a, b);
+    break;
+  case SEXP_NUM_HUG_HUG:
+    r = sexp_max_hugenum_magnitude(ctx, a, b);
+    break;
+#endif
   }
   sexp_gc_release1(ctx);
   return r;
@@ -1021,21 +1182,14 @@ sexp sexp_sub (sexp ctx, sexp a, sexp b) {
   switch ((at * SEXP_NUM_NUMBER_TYPES) + bt) {
   case SEXP_NUM_NOT_NOT: case SEXP_NUM_NOT_FIX:
   case SEXP_NUM_NOT_FLO: case SEXP_NUM_NOT_BIG:
-#if SEXP_USE_RATIOS
-  case SEXP_NUM_NOT_RAT:
-#endif
-#if SEXP_USE_COMPLEX
-  case SEXP_NUM_NOT_CPX:
-#endif
+  sexp_rat_case(SEXP_NUM_NOT_RAT)
+  sexp_cpx_case(SEXP_NUM_NOT_CPX)
+  sexp_hug_case(SEXP_NUM_NOT_HUG)
     r = sexp_type_exception(ctx, NULL, SEXP_NUMBER, a);
     break;
   case SEXP_NUM_FIX_NOT: case SEXP_NUM_FLO_NOT: case SEXP_NUM_BIG_NOT:
-#if SEXP_USE_RATIOS
-  case SEXP_NUM_RAT_NOT:
-#endif
-#if SEXP_USE_COMPLEX
-  case SEXP_NUM_CPX_NOT:
-#endif
+  sexp_rat_case(SEXP_NUM_RAT_NOT)
+  sexp_cpx_case(SEXP_NUM_CPX_NOT)
     r = sexp_type_exception(ctx, NULL, SEXP_NUMBER, b);
     break;
   case SEXP_NUM_FIX_FIX:
@@ -1133,6 +1287,40 @@ sexp sexp_sub (sexp ctx, sexp a, sexp b) {
     }
     break;
 #endif
+#if SEXP_USE_HUGENUMS
+  case SEXP_NUM_HUG_FLO:
+  case SEXP_NUM_HUG_RAT:
+  case SEXP_NUM_HUG_FIX:
+  case SEXP_NUM_HUG_BIG:
+    r = tmp1 = sexp_sub(ctx, b, a);
+    if (sexp_hugenump(r)) r = sexp_copy_hugenum(ctx, r);
+    sexp_negate(r);
+    break;
+  case SEXP_NUM_FLO_HUG:
+    if (sexp_infp(a)) {
+      r = a;
+    } else {
+    /* ... FALLTHROUGH ... */
+  case SEXP_NUM_RAT_HUG:
+  case SEXP_NUM_FIX_HUG:
+  case SEXP_NUM_BIG_HUG:
+      r = sexp_copy_hugenum(ctx, b);
+      sexp_negate(r);
+    }
+    break;
+  case SEXP_NUM_CPX_HUG:
+    b = tmp1 = sexp_make_complex(ctx, b, SEXP_ZERO);
+    r = sexp_complex_sub(ctx, a, b);
+    break;
+  case SEXP_NUM_HUG_HUG:
+    if (sexp_compare_hugenum_magnitude(ctx, a, b, 1) > 0) {
+      r = a;
+    } else {
+      r = tmp1 = sexp_copy_hugenum(ctx, b);
+      sexp_negate(r);
+    }
+    break;
+#endif
   }
   sexp_gc_release2(ctx);
   return r;
@@ -1148,9 +1336,9 @@ sexp sexp_mul (sexp ctx, sexp a, sexp b) {
   switch ((at * SEXP_NUM_NUMBER_TYPES) + bt) {
   case SEXP_NUM_NOT_NOT: case SEXP_NUM_NOT_FIX:
   case SEXP_NUM_NOT_FLO: case SEXP_NUM_NOT_BIG:
-#if SEXP_USE_RATIOS
-  case SEXP_NUM_NOT_RAT:
-#endif
+  sexp_rat_case(SEXP_NUM_NOT_RAT)
+  sexp_cpx_case(SEXP_NUM_NOT_CPX)
+  sexp_hug_case(SEXP_NUM_NOT_HUG)
     r = sexp_type_exception(ctx, NULL, SEXP_NUMBER, a);
     break;
   case SEXP_NUM_FIX_FIX:
@@ -1189,9 +1377,7 @@ sexp sexp_mul (sexp ctx, sexp a, sexp b) {
     break;
 #endif
 #if SEXP_USE_COMPLEX
-#if SEXP_USE_RATIOS
-  case SEXP_NUM_RAT_CPX:
-#endif
+  sexp_rat_case(SEXP_NUM_RAT_CPX)
   case SEXP_NUM_FLO_CPX:
   case SEXP_NUM_FIX_CPX:
   case SEXP_NUM_BIG_CPX:
@@ -1201,6 +1387,33 @@ sexp sexp_mul (sexp ctx, sexp a, sexp b) {
     r = sexp_complex_mul(ctx, a, b);
     break;
 #endif
+#if SEXP_USE_HUGENUMS
+  case SEXP_NUM_FLO_HUG:
+    if (sexp_infp(a)) {
+      r = sexp_mul(ctx, a, sexp_make_fixnum(sexp_hugenum_sign(b)));
+    } else {
+      r = sexp_copy_hugenum(ctx, b);
+      if (sexp_flonum_value(a) < 0) {
+        sexp_negate(r);
+      }
+    }
+    break;
+  case SEXP_NUM_RAT_HUG:
+  case SEXP_NUM_FIX_HUG:
+  case SEXP_NUM_BIG_HUG:
+    r = sexp_copy_hugenum(ctx, b);
+    if (sexp_negativep(a) < 0) {
+      sexp_negate(r);
+    }
+    break;
+  case SEXP_NUM_CPX_HUG:
+    b = tmp = sexp_make_complex(ctx, b, SEXP_ZERO);
+    r = sexp_complex_add(ctx, a, b);
+    break;
+  case SEXP_NUM_HUG_HUG:
+    r = sexp_max_hugenum_magnitude(ctx, a, b);
+    break;
+#endif
   }
   sexp_gc_release1(ctx);
   return r;
@@ -1217,15 +1430,13 @@ sexp sexp_div (sexp ctx, sexp a, sexp b) {
   switch ((at * SEXP_NUM_NUMBER_TYPES) + bt) {
   case SEXP_NUM_NOT_NOT: case SEXP_NUM_NOT_FIX:
   case SEXP_NUM_NOT_FLO: case SEXP_NUM_NOT_BIG:
-#if SEXP_USE_RATIOS
-  case SEXP_NUM_NOT_RAT:
-#endif
+  sexp_rat_case(SEXP_NUM_NOT_RAT)
+  sexp_cpx_case(SEXP_NUM_NOT_CPX)
+  sexp_hug_case(SEXP_NUM_NOT_HUG)
     r = sexp_type_exception(ctx, NULL, SEXP_NUMBER, a);
     break;
   case SEXP_NUM_FIX_NOT: case SEXP_NUM_FLO_NOT: case SEXP_NUM_BIG_NOT:
-#if SEXP_USE_RATIOS
-  case SEXP_NUM_RAT_NOT:
-#endif
+  sexp_rat_case(SEXP_NUM_RAT_NOT)
     r = sexp_type_exception(ctx, NULL, SEXP_NUMBER, b);
     break;
   case SEXP_NUM_FIX_FIX:
@@ -1349,15 +1560,16 @@ sexp sexp_quotient (sexp ctx, sexp a, sexp b) {
   switch ((at * SEXP_NUM_NUMBER_TYPES) + bt) {
   case SEXP_NUM_NOT_NOT: case SEXP_NUM_NOT_FIX:
   case SEXP_NUM_NOT_FLO: case SEXP_NUM_NOT_BIG:
+  sexp_rat_case(SEXP_NUM_NOT_RAT)
+  sexp_cpx_case(SEXP_NUM_NOT_CPX)
+  sexp_hug_case(SEXP_NUM_NOT_HUG)
     r = sexp_type_exception(ctx, NULL, SEXP_FIXNUM, a);
     break;
   case SEXP_NUM_FIX_NOT: case SEXP_NUM_FLO_NOT: case SEXP_NUM_BIG_NOT:
     r = sexp_type_exception(ctx, NULL, SEXP_FIXNUM, b);
     break;
   case SEXP_NUM_FLO_FIX: case SEXP_NUM_FLO_FLO: case SEXP_NUM_FLO_BIG:
-#if SEXP_USE_RATIOS
-  case SEXP_NUM_FLO_RAT:
-#endif
+  sexp_rat_case(SEXP_NUM_FLO_RAT)
     if (sexp_flonum_value(a) != trunc(sexp_flonum_value(a))) {
       r = sexp_type_exception(ctx, NULL, SEXP_FIXNUM, a);
     } else {
@@ -1372,16 +1584,12 @@ sexp sexp_quotient (sexp ctx, sexp a, sexp b) {
 #if SEXP_USE_COMPLEX
   case SEXP_NUM_FLO_CPX: case SEXP_NUM_CPX_FIX: case SEXP_NUM_CPX_FLO:
   case SEXP_NUM_CPX_BIG: case SEXP_NUM_CPX_CPX:
-#if SEXP_USE_RATIOS
-  case SEXP_NUM_CPX_RAT:
-#endif
+  sexp_rat_case(SEXP_NUM_CPX_RAT)
 #endif
     r = sexp_type_exception(ctx, NULL, SEXP_FIXNUM, a);
     break;
   case SEXP_NUM_FIX_FLO: case SEXP_NUM_BIG_FLO:
-#if SEXP_USE_RATIOS
-  case SEXP_NUM_RAT_FLO:
-#endif
+  sexp_rat_case(SEXP_NUM_RAT_FLO)
     if (sexp_flonum_value(b) != trunc(sexp_flonum_value(b))) {
       r = sexp_type_exception(ctx, NULL, SEXP_FIXNUM, b);
     } else {
@@ -1423,15 +1631,16 @@ sexp sexp_remainder (sexp ctx, sexp a, sexp b) {
   switch ((at * SEXP_NUM_NUMBER_TYPES) + bt) {
   case SEXP_NUM_NOT_NOT: case SEXP_NUM_NOT_FIX:
   case SEXP_NUM_NOT_FLO: case SEXP_NUM_NOT_BIG:
+  sexp_rat_case(SEXP_NUM_NOT_RAT)
+  sexp_cpx_case(SEXP_NUM_NOT_CPX)
+  sexp_hug_case(SEXP_NUM_NOT_HUG)
     r = sexp_type_exception(ctx, NULL, SEXP_FIXNUM, a);
     break;
   case SEXP_NUM_FIX_NOT: case SEXP_NUM_FLO_NOT: case SEXP_NUM_BIG_NOT:
     r = sexp_type_exception(ctx, NULL, SEXP_FIXNUM, b);
     break;
   case SEXP_NUM_FLO_FIX: case SEXP_NUM_FLO_FLO: case SEXP_NUM_FLO_BIG:
-#if SEXP_USE_RATIOS
-  case SEXP_NUM_FLO_RAT:
-#endif
+  sexp_rat_case(SEXP_NUM_FLO_RAT)
     if (sexp_flonum_value(a) != trunc(sexp_flonum_value(a))) {
       r = sexp_type_exception(ctx, NULL, SEXP_FIXNUM, a);
     } else {
@@ -1446,16 +1655,12 @@ sexp sexp_remainder (sexp ctx, sexp a, sexp b) {
 #if SEXP_USE_COMPLEX
   case SEXP_NUM_FLO_CPX: case SEXP_NUM_CPX_FIX: case SEXP_NUM_CPX_FLO:
   case SEXP_NUM_CPX_BIG: case SEXP_NUM_CPX_CPX:
-#if SEXP_USE_RATIOS
-  case SEXP_NUM_CPX_RAT:
-#endif
+  sexp_rat_case(SEXP_NUM_CPX_RAT)
 #endif
     r = sexp_type_exception(ctx, NULL, SEXP_FIXNUM, a);
     break;
   case SEXP_NUM_FIX_FLO: case SEXP_NUM_BIG_FLO:
-#if SEXP_USE_RATIOS
-  case SEXP_NUM_RAT_FLO:
-#endif
+  sexp_rat_case(SEXP_NUM_RAT_FLO)
     if (sexp_flonum_value(b) != trunc(sexp_flonum_value(b))) {
       r = sexp_type_exception(ctx, NULL, SEXP_FIXNUM, b);
     } else {
@@ -1502,12 +1707,13 @@ sexp sexp_compare (sexp ctx, sexp a, sexp b) {
     switch ((at * SEXP_NUM_NUMBER_TYPES) + bt) {
     case SEXP_NUM_NOT_NOT: case SEXP_NUM_NOT_FIX:
     case SEXP_NUM_NOT_FLO: case SEXP_NUM_NOT_BIG:
+    sexp_rat_case(SEXP_NUM_NOT_RAT)
+    sexp_cpx_case(SEXP_NUM_NOT_CPX)
+    sexp_hug_case(SEXP_NUM_NOT_HUG)
 #if SEXP_USE_COMPLEX
     case SEXP_NUM_CPX_CPX: case SEXP_NUM_CPX_FIX:
     case SEXP_NUM_CPX_FLO: case SEXP_NUM_CPX_BIG:
-#if SEXP_USE_RATIOS
-    case SEXP_NUM_CPX_RAT:
-#endif
+    sexp_rat_case(SEXP_NUM_CPX_RAT)
 #endif
       r = sexp_type_exception(ctx, NULL, SEXP_NUMBER, a);
       break;
diff --git a/eval.c b/eval.c
index 58a5ee1e..d6851576 100644
--- a/eval.c
+++ b/eval.c
@@ -1308,7 +1308,6 @@ sexp sexp_register_optimization (sexp ctx, sexp self, sexp_sint_t n, sexp f, sex
   }
 
 define_math_op(sexp_exp, exp, sexp_complex_exp)
-define_math_op(sexp_log, log, sexp_complex_log)
 define_math_op(sexp_sin, sin, sexp_complex_sin)
 define_math_op(sexp_cos, cos, sexp_complex_cos)
 define_math_op(sexp_tan, tan, sexp_complex_tan)
@@ -1381,6 +1380,34 @@ sexp sexp_sqrt (sexp ctx, sexp self, sexp_sint_t n, sexp z) {
   return res;
 }
 
+sexp sexp_log_op (sexp ctx, sexp self, sexp_sint_t n, sexp z) {
+  double d;
+  sexp_gc_var1(tmp);
+  if (sexp_flonump(z))
+    d = sexp_flonum_value(z);
+  else if (sexp_fixnump(z))
+    d = (double)sexp_unbox_fixnum(z);
+  maybe_convert_ratio(z)
+  maybe_convert_bignum(z)
+  maybe_convert_complex(z, sexp_complex_log)
+#if SEXP_USE_HUGENUMS
+  else if (sexp_hugenump(z)) {
+    if (sexp_hugenum_length(z) == 2) {
+      sexp_gc_preserve1(ctx, tmp);
+      tmp = sexp_log(ctx, sexp_hugenum_data(z)[0]);
+      tmp = sexp_mul(ctx, tmp, sexp_hugenum_data(z)[1]);
+      sexp_gc_release1(ctx);
+      return tmp;
+    } else {
+      return z;
+    }
+  }
+#endif
+  else
+    return sexp_type_exception(ctx, self, SEXP_NUMBER, z);
+  return sexp_make_flonum(ctx, log(d));
+}
+
 #endif  /* SEXP_USE_MATH */
 
 #if SEXP_USE_RATIOS || !SEXP_USE_FLONUMS
@@ -1403,11 +1430,27 @@ sexp sexp_expt_op (sexp ctx, sexp self, sexp_sint_t n, sexp x, sexp e) {
   return sexp_generic_expt(ctx, x, sexp_unbox_fixnum(e));
 #else
   long double f, x1, e1;
-  sexp res;
+  sexp_gc_var1(res);
 #if SEXP_USE_COMPLEX
   if (sexp_complexp(x) || sexp_complexp(e))
     return sexp_complex_expt(ctx, x, e);
 #endif
+  sexp_gc_preserve1(ctx, res);
+#if SEXP_USE_HUGENUMS
+  if (sexp_hugenump(x)) {
+    if (sexp_hugenum_length(x) == 2 && (!sexp_hugenump(e) || sexp_hugenum_length(e) <= 2)) {
+      res = sexp_make_hugenum(ctx, 2);
+      sexp_hugenum_data(res)[0] = sexp_hugenum_data(x)[0];
+      sexp_hugenum_data(res)[1] = sexp_mul(ctx, sexp_hugenum_data(x)[1], e);
+    } else if (sexp_hugenump(e)) {
+      res = sexp_max_hugenum(ctx, x, e);
+    } else {
+      res = x;
+    }
+  } else if (sexp_hugenump(e)) {
+    res = e;
+  } else
+#endif
 #if SEXP_USE_BIGNUMS
   if (sexp_bignump(e)) {        /* bignum exponent needs special handling */
     if ((x == SEXP_ZERO) || (x == SEXP_NEG_ONE))
@@ -1416,6 +1459,10 @@ sexp sexp_expt_op (sexp ctx, sexp self, sexp_sint_t n, sexp x, sexp e) {
       res = SEXP_ONE;                                  /* 1.0    */
     else if (sexp_flonump(x))
       res = sexp_make_flonum(ctx, pow(sexp_flonum_value(x), sexp_bignum_to_double(e)));
+#if SEXP_USE_HUGENUMS
+    else if (sexp_fixnump(x) || sexp_bignump(x))
+      res = sexp_hugenum2(ctx, x, e);
+#endif
     else
       res = sexp_make_flonum(ctx, pow(10.0, 1e100));   /* +inf.0 */
   } else if (sexp_bignump(x)) {
@@ -1429,14 +1476,17 @@ sexp sexp_expt_op (sexp ctx, sexp self, sexp_sint_t n, sexp x, sexp e) {
 #if SEXP_USE_RATIOS
   else if (sexp_ratiop(x)) {
     if (sexp_fixnump(e)) {
+      sexp_gc_release1(ctx);
       return sexp_generic_expt(ctx, x, sexp_unbox_fixnum(e));
     } else {
       x1 = sexp_ratio_to_double(x);
     }
   }
 #endif
-  else
+  else {
+    sexp_gc_release1(ctx);
     return sexp_type_exception(ctx, self, SEXP_FIXNUM, x);
+  }
   if (sexp_fixnump(e))
     e1 = sexp_unbox_fixnum(e);
   else if (sexp_flonump(e))
@@ -1461,6 +1511,7 @@ sexp sexp_expt_op (sexp ctx, sexp self, sexp_sint_t n, sexp x, sexp e) {
 #if SEXP_USE_BIGNUMS
   }
 #endif
+  sexp_gc_release1(ctx);
   return res;
 #endif  /* !SEXP_USE_FLONUMS */
 }
diff --git a/include/chibi/bignum.h b/include/chibi/bignum.h
index d23262ee..8666f0aa 100644
--- a/include/chibi/bignum.h
+++ b/include/chibi/bignum.h
@@ -65,6 +65,11 @@ SEXP_API sexp sexp_complex_asin (sexp ctx, sexp z);
 SEXP_API sexp sexp_complex_acos (sexp ctx, sexp z);
 SEXP_API sexp sexp_complex_atan (sexp ctx, sexp z);
 #endif
+#if SEXP_USE_HUGENUMS
+SEXP_API sexp sexp_make_hugenum (sexp ctx, sexp_uint_t len);
+SEXP_API sexp sexp_hugenum2 (sexp ctx, sexp base, sexp exponent);
+SEXP_API sexp sexp_max_hugenum (sexp ctx, sexp a, sexp b);
+#endif
 
 #endif  /* ! SEXP_BIGNUM_H */
 
diff --git a/include/chibi/eval.h b/include/chibi/eval.h
index 9c0c6da1..34aed782 100644
--- a/include/chibi/eval.h
+++ b/include/chibi/eval.h
@@ -148,7 +148,8 @@ SEXP_API sexp sexp_print_vm_profile (sexp ctx, sexp self, sexp_sint_t n);
 
 #if SEXP_USE_MATH
 SEXP_API sexp sexp_exp(sexp ctx, sexp self, sexp_sint_t n, sexp z);
-SEXP_API sexp sexp_log(sexp ctx, sexp self, sexp_sint_t n, sexp z);
+SEXP_API sexp sexp_log_op(sexp ctx, sexp self, sexp_sint_t n, sexp z);
+#define sexp_log(ctx, z) sexp_log_op(ctx, NULL, 1, z)
 SEXP_API sexp sexp_sin(sexp ctx, sexp self, sexp_sint_t n, sexp z);
 SEXP_API sexp sexp_cos(sexp ctx, sexp self, sexp_sint_t n, sexp z);
 SEXP_API sexp sexp_tan(sexp ctx, sexp self, sexp_sint_t n, sexp z);
diff --git a/include/chibi/features.h b/include/chibi/features.h
index 1021fb62..c1ed7887 100644
--- a/include/chibi/features.h
+++ b/include/chibi/features.h
@@ -146,6 +146,9 @@
 /* uncomment this if you don't want imaginary number support */
 /* #define SEXP_USE_COMPLEX 0 */
 
+/* uncomment this if you don't want inexact huge number support */
+/* #define SEXP_USE_HUGENUMS 0 */
+
 /* uncomment this if you don't want 1## style approximate digits */
 /* #define SEXP_USE_PLACEHOLDER_DIGITS 0 */
 
@@ -428,6 +431,23 @@
 #define SEXP_USE_COMPLEX SEXP_USE_FLONUMS
 #endif
 
+#ifndef SEXP_USE_HUGENUMS
+#define SEXP_USE_HUGENUMS SEXP_USE_RATIOS
+#endif
+
+/* hugenums imply ratios and complex */
+#if SEXP_USE_HUGENUMS
+#undef SEXP_USE_RATIOS
+#define SEXP_USE_RATIOS 1
+#undef SEXP_USE_COMPLEX
+#define SEXP_USE_COMPLEX 1
+#endif
+
+#ifndef SEXP_MAX_BIGNUM_LENGTH
+#define SEXP_MAX_BIGNUM_LENGTH (128*1024*1024)  /* 128MB */
+#endif
+
+/* either of ratios or complex imply bignums and flonums */
 #if (SEXP_USE_RATIOS || SEXP_USE_COMPLEX)
 #undef SEXP_USE_BIGNUMS
 #define SEXP_USE_BIGNUMS 1
@@ -462,6 +482,10 @@
 #ifndef SEXP_USE_MATH
 #define SEXP_USE_MATH SEXP_USE_FLONUMS && ! SEXP_USE_NO_FEATURES
 #endif
+#if SEXP_USE_HUGENUMS
+#undef SEXP_USE_MATH
+#define SEXP_USE_MATH 1
+#endif
 
 #ifndef SEXP_USE_ESCAPE_NEWLINE
 #define SEXP_USE_ESCAPE_NEWLINE ! SEXP_USE_NO_FEATURES
diff --git a/include/chibi/sexp.h b/include/chibi/sexp.h
index 60e93a24..18f408a9 100755
--- a/include/chibi/sexp.h
+++ b/include/chibi/sexp.h
@@ -132,6 +132,9 @@ enum sexp_types {
 #if SEXP_USE_COMPLEX
   SEXP_COMPLEX,
 #endif
+#if SEXP_USE_HUGENUMS
+  SEXP_HUGENUM,
+#endif
   SEXP_IPORT,
   SEXP_OPORT,
   SEXP_FILENO,
@@ -351,6 +354,10 @@ struct sexp_struct {
       sexp_uint_t data[];
     } bignum;
     struct {
+      sexp_uint_t length;
+      sexp data[];
+    } hugenum;
+    struct {
       sexp numerator, denominator;
     } ratio;
     struct {
@@ -648,6 +655,11 @@ sexp sexp_make_flonum(sexp ctx, double f);
 #else
 #define sexp_complexp(x)    0
 #endif
+#if SEXP_USE_HUGENUMS
+#define sexp_hugenump(x)    (sexp_check_tag(x, SEXP_HUGENUM))
+#else
+#define sexp_hugenump(x)    0
+#endif
 #define sexp_cpointerp(x)   (sexp_check_tag(x, SEXP_CPOINTER))
 #define sexp_exceptionp(x)  (sexp_check_tag(x, SEXP_EXCEPTION))
 #define sexp_procedurep(x)  (sexp_check_tag(x, SEXP_PROCEDURE))
@@ -732,7 +744,11 @@ sexp sexp_make_flonum(sexp ctx, double f);
 
 #if SEXP_USE_FLONUMS
 #define sexp_fp_integerp(x) (sexp_flonum_value(x) == trunc(sexp_flonum_value(x)))
+#if SEXP_USE_HUGENUMS
+#define _or_integer_flonump(x) || (sexp_flonump(x) && sexp_fp_integerp(x)) || sexp_hugenump(x)
+#else
 #define _or_integer_flonump(x) || (sexp_flonump(x) && sexp_fp_integerp(x))
+#endif
 #else
 #define _or_integer_flonump(x)
 #endif
@@ -758,7 +774,11 @@ SEXP_API sexp sexp_make_unsigned_integer(sexp ctx, sexp_luint_t x);
 #if SEXP_USE_FLONUMS
 #define sexp_fixnum_to_flonum(ctx, x) (sexp_make_flonum(ctx, sexp_unbox_fixnum(x)))
 #if SEXP_USE_RATIOS
+#if SEXP_USE_HUGENUMS
+#define sexp_realp(x) (sexp_exact_integerp(x) || sexp_flonump(x) || sexp_ratiop(x) || sexp_hugenump(x))
+#else
 #define sexp_realp(x) (sexp_exact_integerp(x) || sexp_flonump(x) || sexp_ratiop(x))
+#endif
 #else
 #define sexp_realp(x) (sexp_exact_integerp(x) || sexp_flonump(x))
 #endif
@@ -773,11 +793,18 @@ SEXP_API sexp sexp_make_unsigned_integer(sexp ctx, sexp_luint_t x);
 #define sexp_numberp(x) (sexp_realp(x))
 #endif
 
-#define sexp_exact_negativep(x) (sexp_fixnump(x) ? (sexp_unbox_fixnum(x) < 0) \
-                                 : (SEXP_USE_BIGNUMS && sexp_bignump(x)) \
-                                 && (sexp_bignum_sign(x) < 0))
-#define sexp_negativep(x) (sexp_exact_negativep(x) ||                   \
-                           (sexp_flonump(x) && sexp_flonum_value(x) < 0))
+#define sexp_exact_integer_negativep(x)                                 \
+  (sexp_fixnump(x) ? (sexp_unbox_fixnum(x) < 0)                         \
+  : (sexp_bignump(x) && (sexp_bignum_sign(x) < 0)))
+
+#define sexp_exact_negativep(x)                                         \
+  (sexp_ratiop(x) ? sexp_exact_integer_negativep(sexp_ratio_numerator(x)) \
+   : sexp_exact_integer_negativep(x))
+
+#define sexp_negativep(x)                                               \
+   (sexp_flonump(x) ? (sexp_flonum_value(x) < 0)                        \
+    : sexp_hugenump(x) ? (sexp_exact_integer_negativep(sexp_hugenum_data(x)[0])) \
+    : sexp_exact_negativep(x))
 #define sexp_positivep(x) (!(sexp_negativep(x)))
 
 #if SEXP_USE_BIGNUMS
@@ -801,9 +828,11 @@ SEXP_API sexp sexp_make_unsigned_integer(sexp ctx, sexp_luint_t x);
 #endif
 
 #define sexp_negate(x)                                  \
-  if (sexp_flonump(x))                                  \
+  if (sexp_flonump(x)) {                                \
     sexp_negate_flonum(x);                              \
-  else                                                  \
+  } else if (sexp_hugenump(x)) {                        \
+    sexp_negate_exact(sexp_hugenum_data(x)[0]);         \
+  } else                                                \
     sexp_negate_exact(x)
 
 #if SEXP_USE_FLONUMS || SEXP_USE_BIGNUMS
@@ -915,6 +944,9 @@ SEXP_API sexp sexp_make_unsigned_integer(sexp ctx, sexp_luint_t x);
 #define sexp_complex_real(q)   (sexp_pred_field(q, complex, sexp_complexp, real))
 #define sexp_complex_imag(q)   (sexp_pred_field(q, complex, sexp_complexp, imag))
 
+#define sexp_hugenum_length(h) (sexp_pred_field(h, hugenum, sexp_hugenump, length))
+#define sexp_hugenum_data(h)   (sexp_pred_field(h, hugenum, sexp_hugenump, data))
+
 #define sexp_exception_kind(x)      (sexp_field(x, exception, SEXP_EXCEPTION, kind))
 #define sexp_exception_message(x)   (sexp_field(x, exception, SEXP_EXCEPTION, message))
 #define sexp_exception_irritants(x) (sexp_field(x, exception, SEXP_EXCEPTION, irritants))
@@ -1342,13 +1374,13 @@ SEXP_API sexp sexp_display_op (sexp ctx, sexp self, sexp_sint_t n, sexp obj, sex
 SEXP_API sexp sexp_flush_output_op (sexp ctx, sexp self, sexp_sint_t n, sexp out);
 SEXP_API sexp sexp_read_string (sexp ctx, sexp in, int sentinel);
 SEXP_API sexp sexp_read_symbol (sexp ctx, sexp in, int init, int internp);
-SEXP_API sexp sexp_read_number (sexp ctx, sexp in, int base);
+SEXP_API sexp sexp_read_number (sexp ctx, sexp in, int base, int exactp);
 #if SEXP_USE_BIGNUMS
 SEXP_API sexp sexp_read_bignum (sexp ctx, sexp in, sexp_uint_t init,
 				signed char sign, sexp_uint_t base);
 SEXP_API sexp sexp_write_bignum (sexp ctx, sexp a, sexp out, sexp_uint_t base);
 #endif
-SEXP_API sexp sexp_read_float_tail(sexp ctx, sexp in, double whole, int negp);
+SEXP_API sexp sexp_read_float_tail(sexp ctx, sexp in, double whole, int negp, int exactp);
 #if SEXP_USE_COMPLEX
 SEXP_API sexp sexp_read_complex_tail(sexp ctx, sexp in, sexp res);
 #endif
diff --git a/opcodes.c b/opcodes.c
index 971e8903..f643cb4b 100644
--- a/opcodes.c
+++ b/opcodes.c
@@ -192,7 +192,7 @@ _FN2OPT(_I(SEXP_OPORT), _I(SEXP_FIXNUM), _I(SEXP_BOOLEAN), "open-output-file-des
 _FN2OPT(_I(SEXP_OBJECT), _I(SEXP_PROCEDURE), _I(SEXP_FIXNUM), "register-optimization!", _I(600), sexp_register_optimization),
 #if SEXP_USE_MATH
 _FN1(_I(SEXP_NUMBER), _I(SEXP_NUMBER), "exp", 0, sexp_exp),
-_FN1(_I(SEXP_NUMBER), _I(SEXP_NUMBER), "ln", 0, sexp_log),
+_FN1(_I(SEXP_NUMBER), _I(SEXP_NUMBER), "ln", 0, sexp_log_op),
 _FN1(_I(SEXP_NUMBER), _I(SEXP_NUMBER), "sin", 0, sexp_sin),
 _FN1(_I(SEXP_NUMBER), _I(SEXP_NUMBER), "cos", 0, sexp_cos),
 _FN1(_I(SEXP_NUMBER), _I(SEXP_NUMBER), "tan", 0, sexp_tan),
diff --git a/sexp.c b/sexp.c
index d7636d0a..e5782c41 100644
--- a/sexp.c
+++ b/sexp.c
@@ -195,6 +195,9 @@ static struct sexp_type_struct _sexp_type_specs[] = {
 #if SEXP_USE_COMPLEX
   {SEXP_COMPLEX, sexp_offsetof(complex, real), 2, 2, 0, 0, sexp_sizeof(complex), 0, 0, 0, 0, 0, 0, 0, 0, (sexp)"Complex", SEXP_FALSE, SEXP_FALSE, NULL, SEXP_FALSE, NULL, NULL},
 #endif
+#if SEXP_USE_HUGENUMS
+  {SEXP_HUGENUM, sexp_offsetof(hugenum, data), 0, 0, sexp_offsetof(hugenum, length), 1, sexp_sizeof(hugenum), sexp_offsetof(hugenum, length), sizeof(sexp), 0, 0, 0, 0, 0, 0, (sexp)"Hugenum", SEXP_FALSE, SEXP_FALSE, NULL, SEXP_FALSE, NULL, NULL},
+#endif
   {SEXP_IPORT, sexp_offsetof(port, name), 2, 2, 0, 0, sexp_sizeof(port), 0, 0, 0, 0, 0, 0, 0, 0, (sexp)"Input-Port", SEXP_FALSE, SEXP_FALSE, NULL, SEXP_FALSE, NULL, SEXP_FINALIZE_PORT},
   {SEXP_OPORT, sexp_offsetof(port, name), 2, 2, 0, 0, sexp_sizeof(port), 0, 0, 0, 0, 0, 0, 0, 0, (sexp)"Output-Port", SEXP_FALSE, SEXP_FALSE, NULL, SEXP_FALSE, NULL, SEXP_FINALIZE_PORT},
   {SEXP_FILENO, 0, 0, 0, 0, 0, sexp_sizeof(fileno), 0, 0, 0, 0, 0, 0, 0, 0, (sexp)"File-Descriptor", SEXP_FALSE, SEXP_FALSE, NULL, SEXP_FALSE, NULL, SEXP_FINALIZE_FILENO},
@@ -1939,6 +1942,20 @@ sexp sexp_write_one (sexp ctx, sexp obj, sexp out) {
       sexp_write_char(ctx, 'i', out);
       break;
 #endif
+#if SEXP_USE_HUGENUMS
+    case SEXP_HUGENUM:
+      if (sexp_hugenum_length(obj) == 2 && sexp_hugenum_data(obj)[0] == SEXP_TEN) {
+        sexp_write_string(ctx, "1e", out);
+        sexp_write(ctx, sexp_hugenum_data(obj)[1], out);
+      } else {
+        sexp_write(ctx, sexp_hugenum_data(obj)[0], out);
+        for (i=1; i<sexp_hugenum_length(obj); i++) {
+          sexp_write_string(ctx, "->", out);
+          sexp_write(ctx, sexp_hugenum_data(obj)[i], out);
+        }
+      }
+      break;
+#endif
     case SEXP_OPCODE:
       sexp_write_string(ctx, "#<opcode ", out);
       sexp_write(ctx, sexp_opcode_name(obj), out);
@@ -2130,7 +2147,7 @@ sexp sexp_read_string (sexp ctx, sexp in, int sentinel) {
       case 'r': c = '\r'; break; 
       case 't': c = '\t'; break;
       case 'x':
-        res = sexp_read_number(ctx, in, 16);
+        res = sexp_read_number(ctx, in, 16, 1);
         if (sexp_fixnump(res)) {
           c = sexp_read_char(ctx, in);
           if (c != ';') {
@@ -2244,9 +2261,12 @@ sexp sexp_complex_normalize (sexp cpx) {
 
 sexp sexp_read_complex_tail (sexp ctx, sexp in, sexp real) {
   int c = sexp_read_char(ctx, in), c2;
+#if SEXP_USE_HUGENUMS
+  int i;
+#endif
   sexp default_real = SEXP_ZERO;
-  sexp_gc_var1(res);
-  sexp_gc_preserve1(ctx, res);
+  sexp_gc_var2(res, tmp);
+  sexp_gc_preserve2(ctx, res, tmp);
   res = SEXP_VOID;
   if (c=='i' || c=='I') {       /* trailing i, no sign */
   trailing_i:
@@ -2270,11 +2290,34 @@ sexp sexp_read_complex_tail (sexp ctx, sexp in, sexp real) {
       default_real = real;
       real = (c=='-') ? SEXP_NEG_ONE : SEXP_ONE;
       goto trailing_i;
+#if SEXP_USE_HUGENUMS
+    } else if (c=='-' && c2=='>') { /* chained arrow */
+      if (!sexp_exact_integerp(real)) {
+        res = sexp_read_error(ctx, "chains can only follow exact integers", real, in);
+      } else {
+        tmp = sexp_read_number(ctx, in, 10, 1);
+        if (real == SEXP_ONE || tmp == SEXP_ONE) {
+          res = real;
+        } else if (sexp_hugenump(tmp)) {
+          res = sexp_make_hugenum(ctx, sexp_hugenum_length(tmp)+1);
+          sexp_hugenum_data(res)[0] = real;
+          for (i=0; i<sexp_hugenum_length(tmp); i++)
+            sexp_hugenum_data(res)[i+1] = sexp_hugenum_data(tmp)[i];
+        } else if (sexp_exact_integerp(tmp)) {
+          res = sexp_make_hugenum(ctx, 2);
+          sexp_hugenum_data(res)[0] = real;
+          sexp_hugenum_data(res)[1] = tmp;
+        } else {
+          res = sexp_exceptionp(tmp) ? tmp
+            : sexp_read_error(ctx, "invalid chained arrow component", tmp, in);
+        }
+      }
+#endif
     } else {
       sexp_push_char(ctx, c2, in);
       /* read imaginary part */
       if (c=='-') sexp_push_char(ctx, c, in);
-      res = sexp_read_number(ctx, in, 10);
+      res = sexp_read_number(ctx, in, 10, 0);
       if (sexp_complexp(res)) {
         if (sexp_complex_real(res) == SEXP_ZERO)
           sexp_complex_real(res) = real;
@@ -2289,7 +2332,7 @@ sexp sexp_read_complex_tail (sexp ctx, sexp in, sexp real) {
       }
     }
   }
-  sexp_gc_release1(ctx);
+  sexp_gc_release2(ctx);
   return sexp_complex_normalize(res);
 }
 
@@ -2297,7 +2340,7 @@ sexp sexp_read_complex_tail (sexp ctx, sexp in, sexp real) {
 sexp sexp_read_polar_tail (sexp ctx, sexp in, sexp magnitude) {
   sexp_gc_var2(res, theta);
   sexp_gc_preserve2(ctx, res, theta);
-  theta = sexp_read_number(ctx, in, 10);
+  theta = sexp_read_number(ctx, in, 10, 0);
   if (sexp_exceptionp(theta)) {
     res = theta;
   } else if (sexp_complexp(theta) || !sexp_numberp(theta)) {
@@ -2315,12 +2358,11 @@ sexp sexp_read_polar_tail (sexp ctx, sexp in, sexp magnitude) {
 #endif
 #endif
 
-sexp sexp_read_float_tail (sexp ctx, sexp in, double whole, int negp) {
+sexp sexp_read_float_tail (sexp ctx, sexp in, double whole, int negp, int exactp) {
   int c, c2;
-  sexp exponent=SEXP_VOID;
   double val=0.0, scale=0.1, e=0.0;
-  sexp_gc_var1(res);
-  sexp_gc_preserve1(ctx, res);
+  sexp_gc_var2(res, exponent);
+  sexp_gc_preserve2(ctx, res, exponent);
   for (c=sexp_read_char(ctx, in); sexp_isdigit(c);
        c=sexp_read_char(ctx, in), scale*=0.1)
     val += digit_value(c)*scale;
@@ -2333,9 +2375,9 @@ sexp sexp_read_float_tail (sexp ctx, sexp in, double whole, int negp) {
   if (is_precision_indicator(c)) {
     c2 = sexp_read_char(ctx, in);
     if (c2 != '+') sexp_push_char(ctx, c2, in);
-    exponent = sexp_read_number(ctx, in, 10);
+    exponent = sexp_read_number(ctx, in, 10, 1);
     if (sexp_exceptionp(exponent)) {
-      sexp_gc_release1(ctx);
+      sexp_gc_release2(ctx);
       return exponent;
     }
 #if SEXP_USE_COMPLEX
@@ -2345,7 +2387,11 @@ sexp sexp_read_float_tail (sexp ctx, sexp in, double whole, int negp) {
     }
 #endif
     e = (sexp_fixnump(exponent) ? sexp_unbox_fixnum(exponent)
-         : sexp_flonump(exponent) ? sexp_flonum_value(exponent) : 0.0);
+         : sexp_flonump(exponent) ? sexp_flonum_value(exponent)
+#if SEXP_USE_HUGENUMS
+         : (sexp_bignump(exponent) || sexp_hugenump(exponent)) ? (DBL_MAX_EXP+1)
+#endif
+         : 0.0);
 #if SEXP_USE_COMPLEX
     if (sexp_complexp(res)) {
       if (sexp_complex_real(res) == SEXP_ZERO) {
@@ -2353,17 +2399,44 @@ sexp sexp_read_float_tail (sexp ctx, sexp in, double whole, int negp) {
       } else {
         sexp_complex_real(res) = sexp_make_flonum(ctx, val * pow(10, e));
       }
-      sexp_gc_release1(ctx);
+      sexp_gc_release2(ctx);
       return res;
     }
 #endif
   }
-  if (e != 0.0) val *= pow(10, e);
+  if (e != 0.0) {
+#if SEXP_USE_BIGNUMS
+    if (exactp && (val == trunc(val))) {
+      res = sexp_make_integer(ctx, (sexp_sint_t)val);
+      exponent = sexp_expt(ctx, SEXP_TEN, exponent);
+      res = sexp_mul(ctx, res, exponent);
+      sexp_gc_release2(ctx);
+      return res;
+    } else
+#endif
+      val *= pow(10, e);
+  }
+#if SEXP_USE_HUGENUMS
+  if (isinf(val)) {
+    if (sexp_hugenump(exponent)) {
+      res = sexp_expt(ctx, SEXP_TEN, exponent);
+    } else {
+      res = sexp_make_hugenum(ctx, 2);
+      if (sexp_flonump(exponent)) {
+        sexp_hugenum_data(res)[1] = sexp_flonum_value(exponent) > SEXP_MAX_FIXNUM ? sexp_double_to_bignum(ctx, sexp_flonum_value(exponent)) : sexp_make_fixnum((sexp_sint_t)sexp_flonum_value(exponent));
+      } else {
+        sexp_hugenum_data(res)[1] = exponent;
+      }
+      sexp_hugenum_data(res)[0] = SEXP_TEN;
+    }
+  } else
+#endif
 #if SEXP_USE_FLONUMS
-  res = sexp_make_flonum(ctx, val);
-#else
-  res = sexp_make_fixnum((sexp_uint_t)val);
+  if (!exactp)
+    res = sexp_make_flonum(ctx, val);
+  else
 #endif
+    res = sexp_make_fixnum((sexp_sint_t)val);
   if (!is_precision_indicator(c)) {
 #if SEXP_USE_COMPLEX
     if (c=='i' || c=='i' || c=='+' || c=='-') {
@@ -2377,7 +2450,7 @@ sexp sexp_read_float_tail (sexp ctx, sexp in, double whole, int negp) {
     else
       sexp_push_char(ctx, c, in);
   }
-  sexp_gc_release1(ctx);
+  sexp_gc_release2(ctx);
   return res;
 }
 
@@ -2422,7 +2495,7 @@ sexp sexp_ratio_normalize (sexp ctx, sexp rat, sexp in) {
 }
 #endif
 
-sexp sexp_read_number (sexp ctx, sexp in, int base) {
+sexp sexp_read_number (sexp ctx, sexp in, int base, int exactp) {
   sexp_sint_t val = 0, tmp = -1;
   int c, digit, negativep = 0;
 #if SEXP_USE_PLACEHOLDER_DIGITS
@@ -2467,7 +2540,7 @@ sexp sexp_read_number (sexp ctx, sexp in, int base) {
         whole += sexp_placeholder_digit_value(10)*scale;
     if (is_precision_indicator(c)) {
       sexp_push_char(ctx, c, in);
-      return sexp_read_float_tail(ctx, in, whole, negativep);
+      return sexp_read_float_tail(ctx, in, whole, negativep, exactp);
     } else if ((c!=EOF) && !sexp_is_separator(c)) {
       return sexp_read_error(ctx, "invalid numeric syntax after placeholders",
                              sexp_make_character(c), in);
@@ -2481,10 +2554,10 @@ sexp sexp_read_number (sexp ctx, sexp in, int base) {
     if (base != 10)
       return sexp_read_error(ctx, "found non-base 10 float", SEXP_NULL, in);
     if (c!='.') sexp_push_char(ctx, c, in);
-    return sexp_read_float_tail(ctx, in, val, negativep);
+    return sexp_read_float_tail(ctx, in, val, negativep, exactp);
   } else if (c=='/') {
     sexp_gc_preserve2(ctx, res, den);
-    den = sexp_read_number(ctx, in, base);
+    den = sexp_read_number(ctx, in, base, 1);
     if (! (sexp_fixnump(den) || sexp_bignump(den) || sexp_complexp(den)))
       res = (sexp_exceptionp(den)
              ? den : sexp_read_error(ctx, "invalid rational syntax", den, in));
@@ -2705,15 +2778,31 @@ sexp sexp_read_raw (sexp ctx, sexp in) {
   case '#':
     switch (c1=sexp_read_char(ctx, in)) {
     case 'b': case 'B':
-      res = sexp_read_number(ctx, in, 2); break;
+      res = sexp_read_number(ctx, in, 2, 0); break;
     case 'o': case 'O':
-      res = sexp_read_number(ctx, in, 8); break;
+      res = sexp_read_number(ctx, in, 8, 0); break;
     case 'd': case 'D':
-      res = sexp_read_number(ctx, in, 10); break;
+      res = sexp_read_number(ctx, in, 10, 0); break;
     case 'x': case 'X':
-      res = sexp_read_number(ctx, in, 16); break;
+      res = sexp_read_number(ctx, in, 16, 0); break;
     case 'e': case 'E':
-      res = sexp_read(ctx, in);
+      if ((c1=sexp_read_char(ctx, in)) == '#') {
+        switch (c2=sexp_read_char(ctx, in)) {
+        case 'b': case 'B':
+          res = sexp_read_number(ctx, in, 2, 1); break;
+        case 'o': case 'O':
+          res = sexp_read_number(ctx, in, 8, 1); break;
+        case 'd': case 'D':
+          res = sexp_read_number(ctx, in, 10, 1); break;
+        case 'x': case 'X':
+          res = sexp_read_number(ctx, in, 16, 1); break;
+        default:
+          res = sexp_read_error(ctx, "invalid numeric syntax after #e#", sexp_make_character(c2), in); break;
+        }
+      } else {
+        sexp_push_char(ctx, c1, in);
+        res = sexp_read_number(ctx, in, 10, 1);
+      }
 #if SEXP_USE_INFINITIES
       if (sexp_flonump(res)
           && (isnan(sexp_flonum_value(res)) || isinf(sexp_flonum_value(res))))
@@ -2841,7 +2930,7 @@ sexp sexp_read_raw (sexp ctx, sexp in) {
       c2 = sexp_read_char(ctx, in);
       sexp_push_char(ctx, c2, in);
       if ((c1 == 'x' || c1 == 'X') && (sexp_isxdigit(c2))) {
-        res = sexp_read_number(ctx, in, 16);
+        res = sexp_read_number(ctx, in, 16, 1);
         if (sexp_fixnump(res) && sexp_unbox_fixnum(res) >= 0 && sexp_unbox_fixnum(res) <= 0x10FFFF)
           res = sexp_make_character(sexp_unbox_fixnum(res));
         else if (!sexp_exceptionp(res))
@@ -2902,7 +2991,7 @@ sexp sexp_read_raw (sexp ctx, sexp in) {
     if (c1 == EOF || sexp_is_separator(c1)) {
       res = SEXP_RAWDOT;
     } else if (sexp_isdigit(c1)) {
-      res = sexp_read_float_tail(ctx, in, 0, 0);
+      res = sexp_read_float_tail(ctx, in, 0, 0, 0);
     } else {
       res = sexp_read_symbol(ctx, in, '.', 1);
     }
@@ -2925,7 +3014,7 @@ sexp sexp_read_raw (sexp ctx, sexp in) {
     c2 = sexp_read_char(ctx, in);
     if (c2 == '.' || sexp_isdigit(c2)) {
       sexp_push_char(ctx, c2, in);
-      res = sexp_read_number(ctx, in, 10);
+      res = sexp_read_number(ctx, in, 10, 0);
       if ((c1 == '-') && ! sexp_exceptionp(res)) {
 #if SEXP_USE_FLONUMS
         if (sexp_flonump(res))
@@ -2959,6 +3048,11 @@ sexp sexp_read_raw (sexp ctx, sexp in) {
             }
           } else
 #endif
+#if SEXP_USE_HUGENUMS
+          if (sexp_hugenump(res)) {
+            sexp_negate(sexp_hugenum_data(res)[0]);
+          } else
+#endif
             res = sexp_fx_mul(res, SEXP_NEG_ONE);
       }
     } else {
@@ -3007,7 +3101,7 @@ sexp sexp_read_raw (sexp ctx, sexp in) {
   case '0': case '1': case '2': case '3': case '4':
   case '5': case '6': case '7': case '8': case '9':
     sexp_push_char(ctx, c1, in);
-    res = sexp_read_number(ctx, in, 10);
+    res = sexp_read_number(ctx, in, 10, 0);
     break;
   default:
     res = sexp_read_symbol(ctx, in, c1, 1);
@@ -3065,7 +3159,7 @@ sexp sexp_string_to_number_op (sexp ctx, sexp self, sexp_sint_t n, sexp str, sex
       sexp_read_char(ctx, in);
   }
   in = ((sexp_string_data(str)[0] == '#') || base == 10 ?
-        sexp_read(ctx, in) : sexp_read_number(ctx, in, base));
+        sexp_read(ctx, in) : sexp_read_number(ctx, in, base, 0));
   sexp_gc_release1(ctx);
   return sexp_numberp(in) ? in : SEXP_FALSE;
 }