got rid of some arcane module names

lib/pure/collections/hashtables.nim

@@ -18,8 +18,8 @@ type
   TKeyValuePair[A, B] = tuple[slot: TSlotEnum, key: A, val: B]
   TKeyValuePairSeq[A, B] = seq[TKeyValuePair[A, B]]
   THashTable[A, B] = object of TObject
-    counter: int
     data: TKeyValuePairSeq[A, B]
+    counter: int
 
   PHashTable*[A, B] = ref THashTable[A, B] ## use this type to declare tables
 
@@ -32,12 +32,12 @@ iterator pairs*[A, B](t: PHashTable[A, B]): tuple[key: A, val: B] =
   for h in 0..high(t.data):
     if t.data[h].slot == seFilled: yield (t.data[h].key, t.data[h].val)
 
-iterator keys*[A, B](t: PHashTable[A, B]): tuple[key: A, val: B] =
+iterator keys*[A, B](t: PHashTable[A, B]): A =
   ## iterates over any key in the table `t`.
   for h in 0..high(t.data):
     if t.data[h].slot == seFilled: yield t.data[h].key
 
-iterator values*[A, B](t: PHashTable[A, B]): tuple[key: A, val: B] =
+iterator values*[A, B](t: PHashTable[A, B]): B =
   ## iterates over any value in the table `t`.
   for h in 0..high(t.data):
     if t.data[h].slot == seFilled: yield t.data[h].val
@@ -103,6 +103,7 @@ proc del*[A, B](t: PHashTable[A, B], key: A) =
   var index = RawGet(t, key)
   if index >= 0:
     t.data[index].slot = seDeleted
+    dec(t.counter)
 
 proc newHashTable*[A, B](initialSize = 64): PHashTable[A, B] =
   ## creates a new string table that is empty. `initialSize` needs to be
@@ -125,6 +126,110 @@ proc `$`*[A, B](t: PHashTable[A, B]): string =
       result.add($val)
     result.add("}")
 
+
+# ------------------------------ count tables -------------------------------
+
+const
+  deletedCount = -1
+
+type
+  TCountTable*[A] {.final.} = object
+    data: seq[tuple[key: A, val: int]]
+    counter: int
+
+proc len*[A](t: TCountTable[A]): int =
+  ## returns the number of keys in `t`.
+  result = t.counter
+
+iterator pairs*[A](t: TCountTable[A]): tuple[key: A, val: int] =
+  ## iterates over any (key, value) pair in the table `t`.
+  for h in 0..high(t.data):
+    if t.data[h].slot == seFilled: yield (t.data[h].key, t.data[h].val)
+
+iterator keys*[A](t: TCountTable[A]): A =
+  ## iterates over any key in the table `t`.
+  for h in 0..high(t.data):
+    if t.data[h].slot == seFilled: yield t.data[h].key
+
+iterator values*[A](t: TCountTable[A]): int =
+  ## iterates over any value in the table `t`.
+  for h in 0..high(t.data):
+    if t.data[h].slot == seFilled: yield t.data[h].val
+
+proc RawGet[A](t: TCountTable[A], key: A): int =
+  var h: THash = hash(key) and high(t.data) # start with real hash value
+  while t.data[h].slot != seEmpty:
+    if t.data[h].key == key and t.data[h].slot == seFilled:
+      return h
+    h = nextTry(h, high(t.data))
+  result = -1
+
+proc `[]`*[A](t: TCountTable[A], key: A): B =
+  ## retrieves the value at ``t[key]``. If `key` is not in `t`,
+  ## default empty value for the type `B` is returned
+  ## and no exception is raised. One can check with ``hasKey`` whether the key
+  ## exists.
+  var index = RawGet(t, key)
+  if index >= 0: result = t.data[index].val
+
+proc hasKey*[A](t: TCountTable[A], key: A): bool =
+  ## returns true iff `key` is in the table `t`.
+  result = rawGet(t, key) >= 0
+
+proc RawInsert[A](t: TCountTable[A], data: var TKeyValuePairSeq[A, B],
+                     key: A, val: int) =
+  var h: THash = hash(key) and high(data)
+  while data[h].slot == seFilled:
+    h = nextTry(h, high(data))
+  data[h].key = key
+  data[h].val = val
+  data[h].slot = seFilled
+
+proc Enlarge[A](t: TCountTable[A]) =
+  var n: TKeyValuePairSeq[A, B]
+  newSeq(n, len(t.data) * growthFactor)
+  for i in countup(0, high(t.data)):
+    if t.data[i].slot == seFilled: RawInsert(t, n, t.data[i].key, t.data[i].val)
+  swap(t.data, n)
+
+proc `[]=`*[A](t: TCountTable[A], key: A, val: int) =
+  ## puts a (key, value)-pair into `t`.
+  var index = RawGet(t, key)
+  if index >= 0:
+    t.data[index].val = val
+  else:
+    if mustRehash(len(t.data), t.counter): Enlarge(t)
+    RawInsert(t, t.data, key, val)
+    inc(t.counter)
+
+proc del*[A](t: TCountTable[A], key: A) =
+  ## deletes `key` from hash table `t`.
+  var index = RawGet(t, key)
+  if index >= 0:
+    t.data[index].slot = seDeleted
+
+proc newHashTable*[A, B](initialSize = 64): PHashTable[A, B] =
+  ## creates a new string table that is empty. `initialSize` needs to be
+  ## a power of two.
+  assert isPowerOfTwo(initialSize)
+  new(result)
+  result.counter = 0
+  newSeq(result.data, initialSize)
+
+proc `$`*[A](t: TCountTable[A]): string =
+  ## The `$` operator for string tables.
+  if t.len == 0:
+    result = "{:}"
+  else:
+    result = "{"
+    for key, val in pairs(t):
+      if result.len > 1: result.add(", ")
+      result.add($key)
+      result.add(": ")
+      result.add($val)
+    result.add("}")
+
+
 when isMainModule:
   var table = newHashTable[string, float]()
   table["test"] = 1.2345