Change `data` to `enum`

Matches Rust. `Data` is already super overloaded and product ADTs, which are
more common, are better done with `struct`.

13 files changed, 28 insertions, 28 deletions

diff --git a/examples/raytrace.dx b/examples/raytrace.dx
index 4e9ca85d..f51b6764 100644
--- a/examples/raytrace.dx
+++ b/examples/raytrace.dx
@@ -41,7 +41,7 @@ def cross(a:Vec 3, b:Vec 3) -> Vec 3 =
   [a2 * b3 - a3 * b2, a3 * b1 - a1 * b3, a1 * b2 - a2 * b1]
 
 # TODO: Use `data Color = Red | Green | Blue` and ADTs for index sets
-data Image =
+enum Image =
  MkImage(height:Nat, width:Nat, Fin height => Fin width => Color)
 
 xHat : Vec 3 = [1., 0., 0.]
@@ -92,12 +92,12 @@ BlockHalfWidths = Vec 3
 Radius = Float
 Radiance = Color
 
-data ObjectGeom =
+enum ObjectGeom =
   Wall(Direction, Distance)
   Block(Position, BlockHalfWidths, Angle)
   Sphere(Position, Radius)
 
-data Surface =
+enum Surface =
   Matte(Color)
   Mirror
 
@@ -105,7 +105,7 @@ struct OrientedSurface =
   normal  : Direction
   surface : Surface
 
-data Object =
+enum Object =
   PassiveObject(ObjectGeom, Surface)
   # position, half-width, intensity (assumed to point down)
   Light(Position, Float, Radiance)
@@ -169,7 +169,7 @@ def sdScene(scene:Scene n, pos:Position) -> (Object, Distance) given (n|Ix) =
 def calcNormal(obj:Object, pos:Position) -> Direction =
   grad(\p:Position. sdObject(p, obj)) pos | normalize
 
-data RayMarchResult =
+enum RayMarchResult =
   # incident ray, surface normal, surface properties
   HitObj(Ray, OrientedSurface)
   HitLight(Radiance)
diff --git a/lib/diagram.dx b/lib/diagram.dx
index 7b5c52b7..2868c634 100644
--- a/lib/diagram.dx
+++ b/lib/diagram.dx
@@ -6,7 +6,7 @@ struct Point =
  x : Float
  y : Float
 
-data Geom =
+enum Geom =
   PointGeom
   Circle(Float)
   Rectangle(Float, Float)  # width, height
diff --git a/lib/fft.dx b/lib/fft.dx
index 87b28c0f..825a2c6f 100644
--- a/lib/fft.dx
+++ b/lib/fft.dx
@@ -22,7 +22,7 @@ def odd_sized_palindrome(mid:a, seq:n=>a) -> ((n `Either` () `Either` n)=>a) giv
 
 '## Inner FFT functions
 
-data FTDirection =
+enum FTDirection =
   ForwardFT
   InverseFT
 
diff --git a/lib/linalg.dx b/lib/linalg.dx
index 037f692a..925099a6 100644
--- a/lib/linalg.dx
+++ b/lib/linalg.dx
@@ -23,10 +23,10 @@ def lower_tri_identity() -> LowerTriMat n a given(n|Ix, a|Add|Mul)  =
 '## Representing inequalities between indices
 
 # These would be unnecessary if there were syntax for dependent pairs.
-data LowerTriIx(n)    = MkLowerTriIx(   i:n, j:(..i))
-data UpperTriIx(n)    = MkUpperTriIx(   i:n, j:(i..))
-data LowerTriIxExc(n) = MkLowerTriIxExc(i:n, j:(..<i))
-data UpperTriIxExc(n) = MkUpperTriIxExc(i:n, j:(i<..))
+enum LowerTriIx(n)    = MkLowerTriIx(   i:n, j:(..i))
+enum UpperTriIx(n)    = MkUpperTriIx(   i:n, j:(i..))
+enum LowerTriIxExc(n) = MkLowerTriIxExc(i:n, j:(..<i))
+enum UpperTriIxExc(n) = MkUpperTriIxExc(i:n, j:(i<..))
 
 '## Flipping inequalities between indices
 
diff --git a/lib/netpbm.dx b/lib/netpbm.dx
index a5cd6043..deada0ca 100644
--- a/lib/netpbm.dx
+++ b/lib/netpbm.dx
@@ -4,7 +4,7 @@
 
 import parser
 
-data Image =
+enum Image =
   MkImage(rows:Nat, cols:Nat, pixels:(Fin rows => Fin cols => Fin 3 => Word8))
 
 parse_p6 : Parser Image = MkParser \h.
diff --git a/lib/parser.dx b/lib/parser.dx
index 12b82bdc..1ca78095 100644
--- a/lib/parser.dx
+++ b/lib/parser.dx
@@ -25,7 +25,7 @@ struct ParserHandle(h:Heap) =
   input: String
   offset: Ref h Nat
 
-data Parser(a:Type) =
+enum Parser(a:Type) =
   MkParser((given(h:Heap), ParserHandle h )-> {Except, State h} a)
 
 def parse(handle:ParserHandle h, parser:Parser a) -> {Except, State h} a given (a, h)  =
diff --git a/lib/plot.dx b/lib/plot.dx
index f7c00885..2859ddb8 100644
--- a/lib/plot.dx
+++ b/lib/plot.dx
@@ -3,7 +3,7 @@
 import diagram
 import png
 
-data CompactSet(a:Type) =
+enum CompactSet(a:Type) =
   Interval(a, a)
   Singleton(a)
 
diff --git a/lib/prelude.dx b/lib/prelude.dx
index 8c62e15b..fde3cf19 100644
--- a/lib/prelude.dx
+++ b/lib/prelude.dx
@@ -491,7 +491,7 @@ instance VSpace(())
 
 '## Boolean type
 
-data Bool =
+enum Bool =
   False
   True
 
@@ -530,7 +530,7 @@ def b_to_f(x:Bool) -> Float = i_to_f(b_to_i x)
 '## Ordering
 TODO: move this down to with `Ord`?
 
-data Ordering =
+enum Ordering =
   LT
   EQ
   GT
@@ -542,7 +542,7 @@ A [sum type, or tagged union](https://en.wikipedia.org/wiki/Tagged_union) can ho
 For those familiar with the C language, they can be though of as a combination of an `enum` with a `union`.
 Here we define several basic kinds, and some operators on them.
 
-data Maybe(a:Type) =
+enum Maybe(a:Type) =
   Nothing
   Just(a)
 
@@ -558,7 +558,7 @@ def maybe(d:b, f:(a)->b, x:Maybe a) -> b given (a:Type, b:Type) =
     Nothing  -> d
     Just(x') -> f x'
 
-data Either(a:Type, b:Type) =
+enum Either(a:Type, b:Type) =
   Left(a)
   Right(b)
 
@@ -630,7 +630,7 @@ def (:=)(ref:Ref h s, x:s) -> {State h} () given (h:Heap, s|Data) = %put(ref, x)
 
 def ask(ref:Ref h r) -> {Read h} r given (h:Heap, r|Data) = %ask(ref)
 
-data AccumMonoidData(h:Heap, w:Type) = UnsafeMkAccumMonoidData(b:Type, Monoid b)
+enum AccumMonoidData(h:Heap, w:Type) = UnsafeMkAccumMonoidData(b:Type, Monoid b)
 
 interface AccumMonoid(h:Heap, w:Type)
   getAccumMonoidData : AccumMonoidData(h, w)
@@ -1329,7 +1329,7 @@ def deriv_rev(f:(Float)->Float, x:Float) -> Float = (snd vjp(f, x))(1.0)
 
 # XXX: Watch out when editing this data type! We depend on its structure
 # deep inside the compiler (mostly in linearization and during rule registration).
-data SymbolicTangent(a:Type) =
+enum SymbolicTangent(a:Type) =
   ZeroTangent
   SomeTangent(a)
 
@@ -1398,7 +1398,7 @@ def check_deriv(f:(Float)->Float, x:Float) -> Bool =
 
 '## Length-erased lists
 
-data List(a:Type) =
+enum List(a:Type) =
   AsList(n:Nat, elements:(Fin n => a))
 
 instance Eq(List a) given (a|Eq)
@@ -1588,7 +1588,7 @@ def from_nullable_raw_ptr(ptr:RawPtr) -> Maybe (Ptr a) given (a:Type) =
 
 def c_string_ptr(s:CString) -> Maybe (Ptr Char) = from_nullable_raw_ptr s.ptr
 
-data StreamMode =
+enum StreamMode =
   ReadMode
   WriteMode
 
@@ -1629,7 +1629,7 @@ def while(body: () -> {|eff} Bool) -> {|eff} () given (eff:Effects) =
   body' : () -> {|eff} Word8 = \. b_to_w8 $ body()
   %while(body')
 
-data IterResult(a|Data) =
+enum IterResult(a|Data) =
   Continue
   Done(a)
 
diff --git a/lib/set.dx b/lib/set.dx
index babe2ee4..c92c6229 100644
--- a/lib/set.dx
+++ b/lib/set.dx
@@ -44,7 +44,7 @@ def remove_duplicates_from_sorted(xs:n=>a) -> List a given (n|Ix, a|Eq) =
 
 '## Sets
 
-data Set(a|Ord) =
+enum Set(a|Ord) =
   # Guaranteed to be in sorted order with unique elements,
   # as long as no one else uses this constructor.
   # Instead use the "toSet" function below.
diff --git a/misc/dex.el b/misc/dex.el
index de892c45..69cf5f85 100644
--- a/misc/dex.el
+++ b/misc/dex.el
@@ -12,7 +12,7 @@
     ("^:\\w*"                . font-lock-preprocessor-face)
     (,(concat
        "\\bdef\\b\\|\\bfor\\b\\|\\brof\\b\\|\\bcase\\b\\|"
-       "\\bstruct\\b\\|\\bdata\\b\\|\\bwhere\\b\\|\\bof\\b\\|"
+       "\\bstruct\\b\\|\\benum\\b\\|\\bwhere\\b\\|\\bof\\b\\|"
        "\\bif\\b\\|\\bthen\\b\\|\\belse\\b\\|\\binterface\\b\\|"
        "\\binstance\\b\\|\\bgiven\\b\\|\\bdo\\b\\|\\bview\\b\\|"
        "\\bwith\\b\\|\\bself\\b\\|"
diff --git a/src/lib/Lexing.hs b/src/lib/Lexing.hs
index ec916f74..71ff733d 100644
--- a/src/lib/Lexing.hs
+++ b/src/lib/Lexing.hs
@@ -107,7 +107,7 @@ keyWordToken = \case
   ThenKW          -> "then"
   ElseKW          -> "else"
   OfKW            -> "of"
-  DataKW          -> "data"
+  DataKW          -> "enum"
   StructKW        -> "struct"
   InterfaceKW     -> "interface"
   InstanceKW      -> "instance"
diff --git a/src/lib/Types/Core.hs b/src/lib/Types/Core.hs
index daee7511..8e4a43cc 100644
--- a/src/lib/Types/Core.hs
+++ b/src/lib/Types/Core.hs
@@ -2079,7 +2079,7 @@ instance Pretty (TyConParams n) where
   pretty (TyConParams _ _) = undefined
 
 instance Pretty (TyConDef n) where
-  pretty (TyConDef name _ bs cons) = "data" <+> pretty name <+> pretty bs <> pretty cons
+  pretty (TyConDef name _ bs cons) = "enum" <+> pretty name <+> pretty bs <> pretty cons
 
 instance Pretty (DataConDefs n) where
   pretty = undefined
diff --git a/src/lib/Types/Source.hs b/src/lib/Types/Source.hs
index 26fdda5d..803b685b 100644
--- a/src/lib/Types/Source.hs
+++ b/src/lib/Types/Source.hs
@@ -1089,7 +1089,7 @@ instance Pretty (UAlt n) where
 instance Pretty (UTopDecl n l) where
   pretty = \case
     UDataDefDecl (UDataDef nm bs dataCons) bTyCon bDataCons ->
-      "data" <+> p bTyCon <+> p nm <+> spaced (unsafeFromNest bs) <+> "where" <> nest 2
+      "enum" <+> p bTyCon <+> p nm <+> spaced (unsafeFromNest bs) <+> "where" <> nest 2
          (prettyLines (zip (toList $ unsafeFromNest bDataCons) dataCons))
     UStructDecl bTyCon (UStructDef nm bs fields defs) ->
       "struct" <+> p bTyCon <+> p nm <+> spaced (unsafeFromNest bs) <+> "where" <> nest 2