Merge pull request #4367 from kierdavis/4365-tables-clear

Improvements to tables.clear()

lib/pure/collections/tableimpl.nim

@@ -142,7 +142,8 @@ template delImpl() {.dirty.} =
 
 template clearImpl() {.dirty.} =
   for i in 0 .. <t.data.len:
-    t.data[i].hcode = 0
+    when compiles(t.data[i].hcode): # CountTable records don't contain a hcode
+      t.data[i].hcode = 0
     t.data[i].key = default(type(t.data[i].key))
     t.data[i].val = default(type(t.data[i].val))
   t.counter = 0

lib/pure/collections/tables.nim

@@ -118,7 +118,7 @@ template dataLen(t): untyped = len(t.data)
 
 include tableimpl
 
-proc clear*[A, B](t: Table[A, B] | TableRef[A, B]) =
+proc clear*[A, B](t: var Table[A, B] | TableRef[A, B]) =
   ## Resets the table so that it is empty.
   clearImpl()
 
@@ -457,7 +457,7 @@ proc len*[A, B](t: OrderedTable[A, B]): int {.inline.} =
   ## returns the number of keys in `t`.
   result = t.counter
 
-proc clear*[A, B](t: OrderedTable[A, B] | OrderedTableRef[A, B]) =
+proc clear*[A, B](t: var OrderedTable[A, B] | OrderedTableRef[A, B]) =
   ## Resets the table so that it is empty.
   clearImpl()
   t.first = -1
@@ -786,7 +786,7 @@ proc len*[A](t: CountTable[A]): int =
   ## returns the number of keys in `t`.
   result = t.counter
 
-proc clear*[A](t: CountTable[A] | CountTableRef[A]) =
+proc clear*[A](t: var CountTable[A] | CountTableRef[A]) =
   ## Resets the table so that it is empty.
   clearImpl()
   t.counter = 0

tests/collections/ttables.nim

@@ -134,6 +134,29 @@ block mpairsTableTest1:
 block SyntaxTest:
   var x = toTable[int, string]({:})
 
+# Until #4448 is fixed, these tests will fail
+when false:
+  block clearTableTest:
+    var t = data.toTable
+    assert t.len() != 0
+    t.clear()
+    assert t.len() == 0
+
+  block clearOrderedTableTest:
+    var t = data.toOrderedTable
+    assert t.len() != 0
+    t.clear()
+    assert t.len() == 0
+
+  block clearCountTableTest:
+    var t = initCountTable[string]()
+    t.inc("90", 3)
+    t.inc("12", 2)
+    t.inc("34", 1)
+    assert t.len() != 0
+    t.clear()
+    assert t.len() == 0
+
 proc orderedTableSortTest() =
   var t = initOrderedTable[string, int](2)
   for key, val in items(data): t[key] = val

tests/collections/ttablesref.nim

@@ -141,6 +141,31 @@ block anonZipTest:
   let values = @[1, 2, 3]
   doAssert "{a: 1, b: 2, c: 3}" == $ toTable zip(keys, values)
 
+block clearTableTest:
+  var t = newTable[string, float]()
+  t["test"] = 1.2345
+  t["111"] = 1.000043
+  t["123"] = 1.23
+  assert t.len() != 0
+  t.clear()
+  assert t.len() == 0
+
+block clearOrderedTableTest:
+  var t = newOrderedTable[string, int](2)
+  for key, val in items(data): t[key] = val
+  assert t.len() != 0
+  t.clear()
+  assert t.len() == 0
+
+block clearCountTableTest:
+  var t = newCountTable[string]()
+  t.inc("90", 3)
+  t.inc("12", 2)
+  t.inc("34", 1)
+  assert t.len() != 0
+  t.clear()
+  assert t.len() == 0
+
 orderedTableSortTest()
 echo "true"