Change files to ensure correct codegen

025-factorize.dfy

@@ -1,50 +1 @@
-function prod(s: seq<int>) : int {
-  if |s| == 0 then 1 else prod(s[..|s| - 1]) * s[|s| - 1]
-}
 
-method factorize(n: nat) returns (factors: seq<nat>)
-  // pre-conditions-start
-  requires n > 0
-  // pre-conditions-end
-  // post-conditions-start
-  ensures prod(factors) == n
-  // post-conditions-end
-{
-  // impl-start
-  factors := [];
-  ghost var taken := 1;
-  var cur := n;
-  var i := 2;
-  while i * i <= cur
-    // invariants-start
-    invariant prod(factors) == taken
-    invariant taken * cur == n
-    invariant cur >= 1
-    // invariants-end
-  {
-    ghost var pre := cur;
-    ghost var temp := 1;
-    while cur % i == 0 
-      // invariants-start
-      invariant cur >= 1
-      invariant temp * cur == pre
-      invariant prod(factors) == taken * temp 
-      // invariants-end
-      decreases cur - 1
-    {
-      factors := factors + [i];
-
-      cur := cur / i;
-      temp := temp * i;
-      assert 2 <= i && 2 * cur <= i * cur; // assert-line
-    }
-    taken := taken * temp;
-    i := i + 1;
-  }
-  if cur > 1 {
-    factors := factors + [cur];
-    taken := taken * cur;
-  }
-  assert taken == n; // assert-line
-  // impl-end
-}

037-sort_even.dfy

@@ -1,13 +1,13 @@
-method sorted_even(a: seq<int>) returns (sorted_even: seq<int>)
+method sorted_even(a: seq<int>) returns (sorted: seq<int>)
   // pre-conditions-start
   requires |a| > 0
   // pre-conditions-end
   // post-conditions-start
-  ensures |sorted_even| == |a|
-  ensures forall i, j :: 0 <= i < j && 2 * i < |sorted_even| && 2 * j < |sorted_even| ==>
-      sorted_even[2 * i] <= sorted_even[2 * j]
-  ensures forall i :: 0 <= i < |a| && i % 2 == 1 ==> sorted_even[i] == a[i]
-  ensures multiset(a) == multiset(sorted_even)
+  ensures |sorted| == |a|
+  ensures forall i, j :: 0 <= i < j && 2 * i < |sorted| && 2 * j < |sorted| ==>
+      sorted[2 * i] <= sorted[2 * j]
+      ensures forall i :: 0 <= i < |a| && i % 2 == 1 ==> sorted[i] == a[i]
+      ensures multiset(a) == multiset(sorted)
   // post-conditions-end
 {
   // impl-start
@@ -24,7 +24,7 @@ method sorted_even(a: seq<int>) returns (sorted_even: seq<int>)
     i := i + 1;
   }
 
-  sorted_even := SortSeqPred(a, p);
+  sorted := SortSeqPred(a, p);
   // impl-end
 }
 

073-smallest_change.dfy

@@ -1,6 +1,6 @@
 method smallest_change(s: seq<int>) returns (c: int)
   // post-conditions-start
-  ensures c == |set i {:trigger s[i]} | 0 <= i < |s| / 2 && s[i] != s[|s| - 1 - i]|
+  ensures c == |set i | 0 <= i < |s| / 2 && s[i] != s[|s| - 1 - i]|
   // post-conditions-end
 {
   // impl-start

087-get_row.dfy

@@ -1,4 +1,6 @@
-method get_row(lst: seq<seq<int>>, x: int) returns (pos: seq<(int, int)>)
+type SortSeqState = seq<(int, int)>
+
+method get_row(lst: seq<seq<int>>, x: int) returns (pos: SortSeqState)
   // post-conditions-start
   ensures forall i :: 0 <= i < |pos| ==> (
     var (a, b) := pos[i];
@@ -50,7 +52,7 @@ method get_row(lst: seq<seq<int>>, x: int) returns (pos: seq<(int, int)>)
     assert forall i, j :: 0 <= i < |lst| && 0 <= j < |lst[i]| && lst[i][j] == x ==> (i, j) in multiset(pos);
   }
   // assert-end
-  
+
   // assert-start
   assert forall i :: 0 <= i < |pos| ==> (
     var (a, b) := pos[i]; 0 <= a < |lst| && 0 <= b < |lst[a]| && lst[a][b] == x
@@ -71,7 +73,7 @@ function less_eq(a: (int, int), b: (int, int)): bool {
   (x == u && y == v) || less(a, b)
 }
 
-method SortSeq(s: seq<(int, int)>) returns (sorted: seq<(int, int)>)
+method SortSeq(s: SortSeqState) returns (sorted: SortSeqState)
   // post-conditions-start
   ensures forall i, j :: 0 <= i < j < |sorted| ==> less_eq(sorted[i], sorted[j])
   ensures |sorted| == |s|

095-check_dict_case.dfy

@@ -8,7 +8,9 @@ predicate IsUpperCase(s: string)
   forall i :: 0 <= i < |s| ==> 'A' <= s[i] <= 'Z'
 }
 
-method CheckDictCase(dict: map<string, string>) returns (result: bool)
+type DictCase = map<string, string>
+
+method CheckDictCase(dict: DictCase) returns (result: bool)
   // post-conditions-start
   ensures dict == map[] ==> !result
   ensures result ==> (forall k :: k in dict ==> IsLowerCase(k)) || (forall k :: k in dict ==> IsUpperCase(k))

105-by_length.dfy

@@ -2,7 +2,7 @@ method SortReverseAndName(arr: seq<int>) returns (result: seq<string>)
   // post-conditions-start
   ensures |result| <= |arr|
   ensures forall i :: 0 <= i < |result| ==>
-    result[i] in {"One", "Two", "Three", "Four", "Five", "Six", "Seven", "Eight", "Nine"}
+    result[i] in ["One", "Two", "Three", "Four", "Five", "Six", "Seven", "Eight", "Nine"]
   // post-conditions-end
 {
   // impl-start