some stdlib fixes and improvements

lib/hash.rbcvm

@@ -20,3 +20,7 @@ export function fnv1a(bytes) {
 export function int(n) {
   return n;
 }
+
+export function char(c) {
+  return int(ord(c));
+}

lib/hashmap.rbcvm

@@ -3,9 +3,10 @@ module HashMap;
 import "array.rbcvm";
 import "assoclist.rbcvm";
 import "hash.rbcvm";
+import "iter.rbcvm";
 import "string.rbcvm";
 
-let INITIAL_CAPACITY = 2 ** 3;
+let INITIAL_CAPACITY = toint(2 ** 3);
 let LOAD_FACTOR = 0.7;
 
 # hashmap
@@ -20,6 +21,8 @@ function hash_string(str) {
   return Hash.fnv1a(string_bytes(str));
 }
 
+let default_hash = hash_string;
+
 function do_hash(self, key) {
   return self:hash_fn(key) & self:cap - 1;
 }
@@ -31,7 +34,10 @@ function grow(self) {
   self:buckets = Array.new(cap);
   self:load = 0;
 
-  Array.foreach(oldbuckets, function(bucket) {
+  Array.foreach(old_buckets, function(bucket) {
+    if (!bucket) {
+      return;
+    }
     Array.foreach(AssocList.entries(bucket), function(entry) {
       set(self, entry[0], entry[1]);
     });
@@ -44,7 +50,7 @@ export function with_capacity(capacity) {
   return HashMap{
     cap=capacity,
     load=0,
-    hash_fn=hash_string,
+    hash_fn=default_hash,
     buckets=Array.new(capacity),
   };
 }
@@ -80,7 +86,7 @@ export function set(self, key, value) {
 
   AssocList.set(bucket, key, value);
 
-  if (self:load / self:cap < LOAD_FACTOR) {
+  if (self:load / self:cap > LOAD_FACTOR) {
     grow(self);
   }
 }
@@ -114,5 +120,22 @@ export function make_with_hash_function(hash, init_fn) {
 }
 
 export function make(init_fn) {
-  return make_with_hash_function(hash_string, init_fn);
+  return make_with_hash_function(default_hash, init_fn);
+}
+
+export function from_entries_with_hash_function(hash, entries) {
+  let map = new();
+  set_hash_function(map, hash);
+  extend(map, entries);
+  return map;
+}
+
+export function from_entries(entries) {
+  return from_entries_with_hash_function(default_hash, entries);
+}
+
+export function extend(map, entries) {
+  Iter.foreach(entries, function(entry) {
+    set(map, entry[0], entry[1]);
+  });
 }

lib/string.rbcvm

@@ -17,7 +17,7 @@ export function parse_integer(str, base) {
 
   Array.foreach(cs, function(char, i) {
     if (Char.is_digit(char)) {
-      sum = sum + Char.to_digit(char) * base ** i;
+      sum = sum + toint(Char.to_digit(char) * base ** i);
     }
   });