Make sequtils.zip return seq of anonymous tuples

Earlier the tuples had named fields "a" and "b" and that made it
difficult to assign the zip returned seqs to other vars which expected
seqs of tuples with field names other than "a" and "b".

changelog.md

@@ -9,7 +9,7 @@
 
 - `base64.encode` no longer supports `lineLen` and `newLine` use `base64.encodeMIME` instead.
 - `os.splitPath()` behavior synchronized with `os.splitFile()` to return "/" as the dir component of "/root_sub_dir" instead of the empty string.
-
+- `sequtils.zip` now returns a sequence of anonymous tuples i.e. those tuples now do not have fields named "a" and "b".
 
 ### Breaking changes in the compiler
 

lib/pure/collections/sequtils.nim

@@ -202,16 +202,13 @@ proc deduplicate*[T](s: openArray[T], isSorted: bool = false): seq[T] =
       for itm in items(s):
         if not result.contains(itm): result.add(itm)
 
-proc zip*[S, T](s1: openArray[S], s2: openArray[T]): seq[tuple[a: S, b: T]] =
+proc zip*[S, T](s1: openArray[S], s2: openArray[T]): seq[(S, T)] =
   ## Returns a new sequence with a combination of the two input containers.
   ##
   ## The input containers can be of different types.
   ## If one container is shorter, the remaining items in the longer container
   ## are discarded.
   ##
-  ## For convenience you can access the returned tuples through the named
-  ## fields `a` and `b`.
-  ##
   runnableExamples:
     let
       short = @[1, 2, 3]
@@ -223,10 +220,9 @@ proc zip*[S, T](s1: openArray[S], s2: openArray[T]): seq[tuple[a: S, b: T]] =
       zip3 = zip(long, letters)
     assert zip1 == @[(1, 6), (2, 5), (3, 4)]
     assert zip2 == @[(1, "one"), (2, "two"), (3, "three")]
-    assert zip3 == @[(a: 6, b: 'a'), (a: 5, b: 'b'), (a: 4, b: 'c'),
-                     (a: 3, b: 'd')]
-    assert zip1[2].b == 4
-    assert zip2[2].b == "three"
+    assert zip3 == @[(6, 'a'), (5, 'b'), (4, 'c'), (3, 'd')]
+    assert zip1[2][1] == 4
+    assert zip2[2][1] == "three"
 
   var m = min(s1.len, s2.len)
   newSeq(result, m)
@@ -1077,11 +1073,11 @@ when isMainModule:
     assert zip3 == @[(1, 6), (2, 5), (3, 4)]
     assert zip4 == @[(1, "one"), (2, "two"), (3, "three")]
     assert zip5 == @[(1, "one"), (2, "two"), (3, "three")]
-    assert zip1[2].b == 4
-    assert zip2[2].b == "three"
-    assert zip3[2].b == 4
-    assert zip4[2].b == "three"
-    assert zip5[2].b == "three"
+    assert zip1[2][1] == 4
+    assert zip2[2][1] == "three"
+    assert zip3[2][1] == 4
+    assert zip4[2][1] == "three"
+    assert zip5[2][1] == "three"
 
   block: # distribute tests
     let numbers = @[1, 2, 3, 4, 5, 6, 7]

tests/manyloc/argument_parser/argument_parser.nim

@@ -471,7 +471,7 @@ proc build_help*(expected: seq[Tparameter_specification] = @[],
   let width = prefixes.map(proc (x: string): int = 3 + len(x)).max
 
   for line in zip(prefixes, helps):
-    result.add(line.a & spaces(width - line.a.len) & line.b)
+    result.add(line[0] & spaces(width - line[0].len) & line[1])
 
 
 proc echo_help*(expected: seq[Tparameter_specification] = @[],