Added Range (1 to 3) and a bunch of tests for inverse dicts.

lib/core/collections.nom

@@ -40,10 +40,42 @@ test:
     assume [: for $k = $v in {.x = 1}: add {.key = $k, .value = $v}] ==
         [{.key = "x", .value = 1}]
     assume ({.x = 1, .y = 1} + {.y = 10, .z = 10}) == {.x = 1, .y = 11, .z = 10}
+    assume ({.x = 1, .y = 1} - {.y = 10, .z = 10}) == {.x = 1, .y = -9, .z = -10}
     assume ({.x = 1, .y = 1} | {.y = 10, .z = 10}) == {.x = 1, .y = 1, .z = 10}
     assume ({.x = 1, .y = 1} & {.y = 10, .z = 10}) == {.y = 1}
     assume ({.x = 1, .y = 1} ~ {.y = 10, .z = 10}) == {.x = 1, .z = 10}
 
+    # Set compliments:
+    assume (~{.x}).y
+    assume ((~{.x}).x == (nil))
+    $sc = (~{.x, .y})
+    $sc.y = 99
+
+    # For now, whether $sc.y == 99 or $sc.y == (yes) is unspecified,
+        (but the actual behavior is (yes))
+    assume ($sc.y and (not $sc.x))
+    assume ($sc == ((~{.x, .y}) | {.y = 99}))
+    
+    # Both sets:
+    assume (({.x, .y} & {.y, .z}) == {.y})
+    assume (({.x, .y} | {.y, .z}) == {.x, .y, .z})
+    assume (({.x, .y} ~ {.y, .z}) == {.z, .x})
+    
+    # Mixed:
+    assume (({.x, .y} & (~{.y, .z})) == {.x})
+    assume (({.x, .y} | (~{.y, .z})) == (~{.z}))
+    assume (({.x, .y} ~ (~{.y, .z})) == (~{.x}))
+    
+    # Mixed reversed:
+    assume (((~{.y, .z}) & {.x, .y}) == {.x})
+    assume (((~{.y, .z}) | {.x, .y}) == (~{.z}))
+    assume (((~{.y, .z}) ~ {.x, .y}) == (~{.x}))
+    
+    # Both set compliments:
+    assume (((~{.x, .y}) & (~{.y, .z})) == (~{.x, .y, .z}))
+    assume (((~{.x, .y}) | (~{.y, .z})) == (~{.y}))
+    assume (((~{.x, .y}) ~ (~{.y, .z})) == {.x, .z})
+
 test:
     assume ((entries in {.x = 1}) == [{.key = "x", .value = 1}])
 
@@ -131,3 +163,71 @@ external:
                 $unique, add $
                 $seen.$ = (yes)
         return $unique
+
+# Ranges:
+test:
+    $r = (3 to 5)
+    assume ($r.2 == 4)
+    assume ($r is "a Range")
+    assume ((1 to 10, backwards) == (10 to 1 by -1))
+    assume ((#(1 to 10 by 2)) == 5)
+    $visited = []
+    for $ in (1 to 10 by 2):
+        $visited, add $
+    assume ($visited == [1, 3, 5, 7, 9])
+    $r = (1 to 10 by 2)
+    $visited = []
+    for $ in $r:
+        $visited, add $
+    assume ($visited == [1, 3, 5, 7, 9])
+$(inext) = (=lua "ipairs({})")
+$range_mt = {
+    .__type = "a Range"
+    .__index =
+        for ($self's $key):
+            if ($key is "a Number"):
+                if (($key % 1) != 0):
+                    return (nil)
+                $i = ($self.first + ($key - 1) * $self.step)
+                if ($self.step > 0):
+                    if ($i > $self.last):
+                        return (nil)
+                ..else:
+                    if ($i < $self.last):
+                        return (nil)
+                return $i
+            return $range_mt.$key
+    
+    .__len =
+        for $self:
+            $len = (($self.last - $self.first) / $self.step + 1)
+            if ($len < 0):
+                $len = 0
+            return ($len, rounded down)
+    
+    .__eq =
+        for ($self == $other)
+            (($self's metatable) == ($other's metatable)) and
+                ($self.first == $other.first) and
+                    ($self.last == $other.last) and ($self.step == $other.step)
+    
+    .backwards = (for $self ($self.last to $self.first by (- $self.step)))
+    .__ipairs = (for $self: return $(inext) $self 0)
+    .as_text =
+        for $self:
+            if ($self.step == 1):
+                return "(\($self.first) to \($self.last))"
+            ..else:
+                return "(\($self.first) to \($self.last) by \($self.step))"
+}
+$range_mt.reversed = $range_mt.backwards
+$range_mt.__unm = $range_mt.backwards
+$range_mt.__tostring = $range_mt.as_text
+$range_mt.as_nomsu = $range_mt.as_text
+set $range_mt's metatable to (nil)
+external:
+    ($first to $last by $step) means
+        setmetatable {.first = $first, .last = $last, .step = $step} $range_mt
+    
+    ($first to $last) means
+        setmetatable {.first = $first, .last = $last, .step = 1} $range_mt