Move and deduplicate hash functions

Author: TimWhiting

CHANGELOG

@@ -0,0 +1,3 @@
+# Oct 9th 2025
+
+- Deduplicated and moved `when-resize` / `resizer` to `std/data/hash` from `hashset` / `hashmap`, and `pub import`ed `hash` from those modules. 

std/data/hash.kk

@@ -93,5 +93,16 @@ pub fun either/hash( e : either<l, r>, ?l/hasher : (l, int64) -> int, ?r/hasher
   hash-vector-int64( vec, seed )
 
 
+// Internal function that dictates when to resize the hash-set. This can be overridden with implicits.
+pub fun when-resize( table-size : int, item-count : int ) : bool
+  if 2 * table-size <= item-count then
+    True
+  else
+    False
+
+// Internal function that determines the new size of a hash-set when inserting. This can be overridden with implicits.
+pub fun resizer( table-size : int, item-count : int ) : int
+   item-count * 2
+
 fun example()
   seed.println

std/data/hashmap.kk

@@ -9,7 +9,7 @@
 module std/data/hashmap
 import std/core-extras
 import std/num/int64
-import std/data/hash
+pub import std/data/hash
 
 
 pub struct hash-map<k, v>
@@ -100,17 +100,6 @@ fun helper/rehash( v : vector<list<(k, v)>>, buckets : list<(k, v)>, seed : int6
       val new-v = v.unsafe-set( position, Cons( (key, value), v.unsafe-idx( position.ssize_t ) ) )
       helper/rehash( new-v, xs, seed )
 
-// Internal function that dictates when to resize the hash-map. This can be overridden with implicits.
-pub fun when-resize( table-size : int, item-count : int ) : bool
-  if 2 * table-size <= item-count then
-    True
-  else
-    False
-
-// Internal function that determines the new size of a hash-map when inserting. This can be overridden with implicits.
-pub fun resizer( table-size : int, item-count : int ) : int
-   item-count * 2
-
 // Inserts a `value` into the hash-map with a given `key`.
 pub fun insert( hm : hash-map<k,v>, key : k, value : v, ?hash : (k, int64) -> int, ?(==) : (k, k) -> bool, ?when-resize : (int, int) -> bool, ?resizer : (int, int) -> int ) : hash-map<k, v>
   val the-hash = hash(key, hm.seed)

std/data/hashset.kk

@@ -9,7 +9,7 @@
 module std/data/hashset
 import std/num/int64
 import std/core-extras
-import std/data/hash
+pub import std/data/hash
 
 val int-hash : (int, int64) -> int = int/hash
 val char-hash : (char, int64) -> int = char/hash
@@ -100,18 +100,6 @@ fun helper/rehash( v : vector<list<v>>, buckets : list<v>, seed : int64, ?hash :
       val new-v = v.unsafe-set( position, Cons( value, v.unsafe-idx( position.ssize_t ) ) )
       helper/rehash( new-v, xs, seed )
 
-
-// Internal function that dictates when to resize the hash-set. This can be overridden with implicits.
-pub fun when-resize( table-size : int, item-count : int ) : bool
-  if 2 * table-size <= item-count then
-    True
-  else
-    False
-
-// Internal function that determines the new size of a hash-set when inserting. This can be overridden with implicits.
-pub fun resizer( table-size : int, item-count : int ) : int
-   item-count * 2
-
 // Inserts a `value` into the hash-set.
 pub fun insert( hs : hash-set<v>, value : v, ?hash : (v, int64) -> int, ?(==) : (v, v) -> bool, ?when-resize : (int, int) -> bool, ?resizer : (int, int) -> int ) : hash-set<v>
   val the-hash = hash(value, hs.seed)