defclass reimagined

defclass now has a new syntax:

 (defclass Name [BaseList]
   [property value
    property value] ;; optional

   (defn method [self]
     self.property))

Anything after the optional property list (which will be translated to a
setv within the class context) will be added to the class body. This
allows one to have side effects and complex expressions within the class
definition.

As a side effect, defining methods is much more friendly now!

Closes #850.

Signed-off-by: Gergely Nagy <algernon@madhouse-project.org>

docs/language/api.rst

@@ -357,7 +357,9 @@ attributes of the new class as two item vectors.
 .. code-block:: clj
 
     (defclass class-name [super-class-1 super-class-2]
-      [[attribute value]])
+      [attribute value]
+
+      (defn method [self] (print "hello!")))
 
 Both values and functions can be bound on the new class as shown by the example
 below:
@@ -365,9 +367,10 @@ below:
 .. code-block:: clj
 
     => (defclass Cat []
-    ...  [[age None]
+    ...  [age None
-    ...   [colour "white"]
+    ...   colour "white"]
-    ...   [speak (fn [self] (print "Meow"))]])
+    ...
+    ...  (defn speak [self] (print "Meow")))
 
     => (def spot (Cat))
     => (setv spot.colour "Black")

docs/tutorial.rst

@@ -477,17 +477,14 @@ In Hy:
 
   (defclass FooBar [object]
     "Yet Another Example Class"
-    [[--init--
-      (fn [self x]
-        (setv self.x x)
-        ; Currently needed for --init-- because __init__ needs None
-        ; Hopefully this will go away :)
-        None)]
 
-     [get-x
+    (defn --init-- [self x]
-      (fn [self]
+      (setv self.x x)
-        "Return our copy of x"
+      None)
-        self.x)]])
+
+    (defn get-x [self]
+      "Return our copy of x"
+      self.x))
 
 
 You can also do class-level attributes.  In Python::
@@ -502,9 +499,9 @@ In Hy:
 .. code-block:: clj
 
   (defclass Customer [models.Model]
-    [[name (models.CharField :max-length 255})]
+    [name (models.CharField :max-length 255})
-     [address (models.TextField)]
+     address (models.TextField)
-     [notes (models.TextField)]])
+     notes (models.TextField)])
 
 Hy <-> Python interop
 =====================

hy/compiler.py

@@ -2238,15 +2238,15 @@ class HyASTCompiler(object):
 
     @builds("defclass")
     @checkargs(min=1)
-    def compile_class_expression(self, expression):
+    def compile_class_expression(self, expressions):
-        expression.pop(0)  # class
+        expressions.pop(0)  # class
 
-        class_name = expression.pop(0)
+        class_name = expressions.pop(0)
 
-        if expression:
+        if expressions:
-            base_list = expression.pop(0)
+            base_list = expressions.pop(0)
             if not isinstance(base_list, HyList):
-                raise HyTypeError(expression,
+                raise HyTypeError(expressions,
                                   "Bases class must be a list")
             bases_expr, bases, _ = self._compile_collect(base_list)
         else:
@@ -2256,8 +2256,8 @@ class HyASTCompiler(object):
         body = Result()
 
         # grab the doc string, if there is one
-        if expression and isinstance(expression[0], HyString):
+        if expressions and isinstance(expressions[0], HyString):
-            docstring = expression.pop(0)
+            docstring = expressions.pop(0)
             symb = HySymbol("__doc__")
             symb.start_line = docstring.start_line
             symb.start_column = docstring.start_column
@@ -2266,31 +2266,25 @@ class HyASTCompiler(object):
                                          docstring.start_column)
             body += body.expr_as_stmt()
 
-        if expression:
+        if expressions and isinstance(expressions[0], HyList) \
-            try:
+           and not isinstance(expressions[0], HyExpression):
-                body_expression = iter(expression.pop(0))
+            expr = expressions.pop(0)
-            except TypeError:
+            body += self.compile(
-                raise HyTypeError(
+                HyExpression([
-                    expression,
+                    HySymbol("setv")
-                    "Wrong argument type for defclass attributes definition.")
+                ] + expr).replace(expr)
-            for b in body_expression:
+            )
-                if isinstance(b, HyExpression):
+
-                    b = macroexpand(b, self.module_name)
+        for expression in expressions:
-                if len(b) != 2:
+            body += self.compile(macroexpand(expression, self.module_name))
-                    raise HyTypeError(
-                        expression,
-                        "Wrong number of argument in defclass attribute.")
-                body += self._compile_assign(b[0], b[1],
-                                             b.start_line, b.start_column)
-                body += body.expr_as_stmt()
 
         if not body.stmts:
-            body += ast.Pass(lineno=expression.start_line,
+            body += ast.Pass(lineno=expressions.start_line,
-                             col_offset=expression.start_column)
+                             col_offset=expressions.start_column)
 
         return bases + ast.ClassDef(
-            lineno=expression.start_line,
+            lineno=expressions.start_line,
-            col_offset=expression.start_column,
+            col_offset=expressions.start_column,
             decorator_list=[],
             name=ast_str(class_name),
             keywords=[],

tests/native_tests/contrib/meth.hy

@@ -2,12 +2,11 @@
 
 (defclass FakeMeth []
   "Mocking decorator class"
-  [[rules {}]
+  [rules {}]
-   [route (fn [self rule &kwargs options]
+  (defn route [self rule &kwargs options]
-            (fn [f]
+    (fn [f]
-              (assoc self.rules rule (, f options))
+      (assoc self.rules rule (, f options))
-              f))]])
+      f)))
-
 
 (defn test_route []
   (let [[app (FakeMeth)]]

tests/native_tests/defclass.hy

@@ -23,7 +23,7 @@
 (defn test-defclass-attrs []
   "NATIVE: test defclass attributes"
   (defclass A []
-    [[x 42]])
+    [x 42])
   (assert (= A.x 42))
   (assert (= (getattr (A) "x")  42)))
 
@@ -31,9 +31,9 @@
 (defn test-defclass-attrs-fn []
   "NATIVE: test defclass attributes with fn"
   (defclass B []
-    [[x 42]
+    [x 42
-     [y (fn [self value]
+     y (fn [self value]
-          (+ self.x value))]])
+         (+ self.x value))])
   (assert (= B.x 42))
   (assert (= (.y (B) 5) 47))
   (let [[b (B)]]
@@ -44,17 +44,17 @@
 (defn test-defclass-dynamic-inheritance []
   "NATIVE: test defclass with dynamic inheritance"
   (defclass A [((fn [] (if true list dict)))]
-    [[x 42]])
+    [x 42])
   (assert (isinstance (A) list))
   (defclass A [((fn [] (if false list dict)))]
-    [[x 42]])
+    [x 42])
   (assert (isinstance (A) dict)))
 
 
 (defn test-defclass-no-fn-leak []
   "NATIVE: test defclass attributes with fn"
   (defclass A []
-    [[x (fn [] 1)]])
+    [x (fn [] 1)])
   (try
    (do
     (x)
@@ -64,13 +64,13 @@
 (defn test-defclass-docstring []
   "NATIVE: test defclass docstring"
   (defclass A []
-    [[--doc-- "doc string"]
+    [--doc-- "doc string"
-     [x 1]])
+     x 1])
   (setv a (A))
   (assert (= a.__doc__ "doc string"))
   (defclass B []
     "doc string"
-    [[x 1]])
+    [x 1])
   (setv b (B))
   (assert (= b.x 1))
   (assert (= b.__doc__ "doc string"))
@@ -78,7 +78,7 @@
     "begin a very long multi-line string to make
      sure that it comes out the way we hope
      and can span 3 lines end."
-    [[x 1]])
+    [x 1])
   (setv mL (MultiLine))
   (assert (= mL.x 1))
   (assert (in "begin" mL.__doc__))
@@ -86,8 +86,26 @@
 
 (defn test-defclass-macroexpand []
   "NATIVE: test defclass with macro expand"
-  (defmacro M [] `[x (fn [self x] (setv self._x x))])
+  (defmacro M [] `(defn x [self x] (setv self._x x)))
-  (defclass A [] [(M)])
+  (defclass A [] (M))
   (setv a (A))
   (a.x 1)
   (assert (= a._x 1)))
+
+(defn test-defclass-syntax []
+  "NATIVE: test defclass syntax with properties and methods and side-effects"
+  (setv foo 1)
+  (defclass A []
+    [x 1
+     y 2]
+    (global foo)
+    (setv foo 2)
+    (defn greet [self]
+      "Greet the caller"
+
+      "hello!"))
+  (setv a (A))
+  (assert (= a.x 1))
+  (assert (= a.y 2))
+  (assert foo 2)
+  (assert (.greet a) "hello"))

tests/native_tests/mathematics.hy

@@ -145,21 +145,21 @@
 
 
 (defclass HyTestMatrix [list]
-  [[--matmul--
+  [--matmul--
-    (fn [self other]
+   (fn [self other]
-      (let [[n (len self)]
+     (let [[n (len self)]
-            [m (len (. other [0]))]
+           [m (len (. other [0]))]
-            [result []]]
+           [result []]]
-        (for [i (range m)]
+       (for [i (range m)]
-          (let [[result-row []]]
+         (let [[result-row []]]
-            (for [j (range n)]
+           (for [j (range n)]
-              (let [[dot-product 0]]
+             (let [[dot-product 0]]
-                (for [k (range (len (. self [0])))]
+               (for [k (range (len (. self [0])))]
-                  (+= dot-product (* (. self [i] [k])
+                 (+= dot-product (* (. self [i] [k])
-                                     (. other [k] [j]))))
+                                    (. other [k] [j]))))
-                (.append result-row dot-product)))
+               (.append result-row dot-product)))
-            (.append result result-row)))
+           (.append result result-row)))
-        result))]])
+       result))])
 
 (def first-test-matrix (HyTestMatrix [[1 2 3]
                                       [4 5 6]

tests/native_tests/with_decorator.hy

@@ -13,7 +13,7 @@
 
 (with-decorator bardec
   (defclass cls []
-    [[my_attr 456]]))
+    [my_attr 456]))
 
 (defn test-decorator-clobbing []
   "NATIVE: Tests whether nested decorators work"

tests/native_tests/with_test.hy

@@ -1,16 +1,13 @@
 (defclass WithTest [object]
-  [(--init-- 
+  (defn --init-- [self val]
-    (fn [self val]
+    (setv self.val val)
-      (setv self.val val)
+    None)
-      None))
 
-  (--enter--
+  (defn --enter-- [self]
-    (fn [self]
+    self.val)
-      self.val))
 
-  (--exit--
+  (defn --exit-- [self type value traceback]
-    (fn [self type value traceback]
+    (setv self.val None)))
-      (setv self.val None)))])
 
 (defn test-single-with []
   "NATIVE: test a single with"