Simplified the syntax of defdataclass.

simalq/commands.hy

@@ -27,15 +27,15 @@
 (defdataclass Walk [Action]
   "Try to walk one step in the given direction, or attack something
   that's in the way with your sword."
-  [direction]
+  :fields [direction]
   :frozen T)
 (defdataclass Shoot [Action]
   "Fire an arrow in the given direction."
-  [direction]
+  :fields [direction]
   :frozen T)
 (defdataclass UseItem [Action]
   "Apply an item from your inventory."
-  [item-ix target-x target-y]
+  :fields [item-ix target-x target-y]
   :frozen T)
 
 (defdataclass Help [Command]
@@ -60,11 +60,11 @@
 (defdataclass ShiftHistory [Command]
   "{details}"
   ; Undo or redo.
-  [steps]
+  :fields [steps]
   :frozen T)
 (defdataclass SaveGame [Command]
   "Save the game, {details}."
-  [kind]
+  :fields [kind]
   :frozen T)
 (defdataclass LoadGame [Command]
   "Load a saved game.")

simalq/display.hy

@@ -25,7 +25,7 @@
 (defdataclass ColorChar []
   "A character with a foreground and background color. Colors can
   be `None` or a symbol (a key of `color.by-name`)."
-  [char fg bg])
+  :fields [char fg bg])
 
 (defn colorstr [s [fg None] [bg None]]
   "Convert a string to a colorstr, i.e., a list of `ColorChar`s."

simalq/geometry.hy

@@ -12,7 +12,7 @@
 (defdataclass Map []
   "A level layout."
 
-  [wrap-x wrap-y data width height]
+  :fields [wrap-x wrap-y data width height]
     ; `wrap-x` and `wrap-y` are Booleans.
     ; `data` is a tuple of tuples representing the squares of the map.
     ; Each tile is itself a list representing a stack of tiles on
@@ -33,7 +33,7 @@
 
 
 (defdataclass Direction []
-  [name x y]
+  :fields [name x y]
   :frozen T)
 ((fn []
   ; Define the direction constants (`Direction.N`, `.NE`, etc.)
@@ -72,7 +72,7 @@
 (defdataclass Pos []
   "A position; a point on a map."
 
-  [map x y]
+  :fields [map x y]
   :frozen T
 
   (defmeth __init__ [map x y]

simalq/macros.hy

@@ -3,21 +3,21 @@
 
 
 (defmacro defdataclass [class-name superclasses #* rest]
-  (setv   rest (list rest)  docstring []  fields []  field-defaults []  kwargs [])
+  (setv   rest (list rest)  docstring [])
   (when (and rest (isinstance (get rest 0) hy.models.String))
     (.append docstring (.pop rest 0)))
-  (when rest (cond
-    (= (get rest 0) ':field-defaults)
-      (do
-        (.pop rest 0)
-        (setv field-defaults (.pop rest 0)))
-    (isinstance (get rest 0) hy.models.List)
-      (setv fields (.pop rest 0))
-    True
-      (raise ValueError)))
+  (setv  kwargs []  fields []  field-defaults [])
   (while (and rest (isinstance (get rest 0) hy.models.Keyword))
-    (.append kwargs (.pop rest 0))
-    (.append kwargs (.pop rest 0)))
+    (setv [k v #* rest] rest)
+    (cond
+      (= k ':fields)
+        (setv fields v)
+      (= k ':field-defaults)
+        (setv field-defaults v)
+      True
+        (.extend kwargs [k v])))
+  (assert (not (and fields field-defaults)))
+    ; `field-defaults` defines `fields` implicitly.
   (unless (or fields field-defaults)
     (.extend kwargs '[:frozen True]))
   `(defclass

simalq/quest.hy

@@ -12,7 +12,7 @@
 
 (defdataclass Quest []
   "A scenario or campaign; a sequence of levels to play."
-  [name title authors starting-hp levels]
+  :fields [name title authors starting-hp levels]
   :frozen T)
 
 (defn start-quest [quest [rules None]]
@@ -32,7 +32,8 @@
 
 (defdataclass Level []
   "A map and associated data for playing it."
-  [n title player-start next-level
+  :fields [
+    n title player-start next-level
     poison-intensity time-limit exit-speed moving-exit-start
     map]
   ; Poison intensity is a fraction.Fraction, the amount of poison to