added for and with macros

Fixed up anaphoric.hy and added the tests too native_tests/__init__.py

added __init__.hy

docs/language/api.rst

@@ -441,50 +441,34 @@ first / car
 
 
 for
----
-
-`for` macro is used to build nested `foreach` loops. The macro takes two
-parameters, first being a vector specifying collections to iterate over and 
-variables to bind. The second parameter is a statement which is executed during
-each loop:
-
-.. code-block:: clj
-
-    (for [x iter y iter] stmt)
-
-    (foreach [x iter]
-      (foreach [y iter] stmt))
-
-
-foreach
 -------
 
-`foreach` is used to call a function for each element in a list or vector.
+`for` is used to call a function for each element in a list or vector.
 Results are discarded and None is returned instead. Example code iterates over
 collection and calls side-effect to each element in the collection:
 
 .. code-block:: clj
 
     ;; assuming that (side-effect) is a function that takes a single parameter
-    (foreach [element collection] (side-effect element))
+    (for [[element collection]] (side-effect element))
 
-    ;; foreach can have an optional else block
+    ;; for can have an optional else block
-    (foreach [element collection] (side-effect element)
+    (for [[element collection]] (side-effect element)
          (else (side-effect-2)))
 
-The optional `else` block is executed only if the `foreach` loop terminates
+The optional `else` block is executed only if the `for` loop terminates
 normally. If the execution is halted with `break`, the `else` does not execute.
 
 .. code-block:: clj
 
-    => (foreach [element [1 2 3]] (if (< element 3)
+    => (for [[element [1 2 3]]] (if (< element 3)
     ...                             (print element) 
     ...                             (break))
     ...    (else (print "loop finished")))
     1
     2
 
-    => (foreach [element [1 2 3]] (if (< element 4)
+    => (for [[element [1 2 3]]] (if (< element 4)
     ...                             (print element)
     ...                             (break))
     ...    (else (print "loop finished")))
@@ -635,7 +619,7 @@ function is defined and passed to another function for filtering output.
     ...             {:name "Dave" :age 5}])
 
     => (defn display-people [people filter]
-    ...  (foreach [person people] (if (filter person) (print (:name person)))))
+    ...  (for [[person people]] (if (filter person) (print (:name person)))))
 
     => (display-people people (fn [person] (< (:age person) 25)))
     Alice
@@ -949,16 +933,18 @@ context to an argument or ignore it completely, as shown below:
 
 .. code-block:: clj
 
-    (with [arg (expr)] block)
+    (with [[arg (expr)]] block)
 
-    (with [(expr)] block)
+    (with [[(expr)]] block)
+
+    (with [[arg (expr)] [(expr)]] block)
 
 The following example will open file `NEWS` and print its content on screen. The
 file is automatically closed after it has been processed.
 
 .. code-block:: clj
 
-    (with [f (open "NEWS")] (print (.read f)))
+    (with [[f (open "NEWS")]] (print (.read f)))
 
 
 with-decorator
@@ -996,7 +982,7 @@ infinite series without consuming infinite amount of memory.
 .. code-block:: clj
 
     => (defn multiply [bases coefficients]
-    ...  (foreach [(, base coefficient) (zip bases coefficients)]
+    ...  (for [[(, base coefficient) (zip bases coefficients)]]
     ...   (yield (* base coefficient))))
 
     => (multiply (range 5) (range 5))

hy/compiler.py

@@ -1177,14 +1177,18 @@ class HyASTCompiler(object):
         fn.stmts[-1].decorator_list = decorators
         return ret + fn
 
-    @builds("with")
+    @builds("with*")
     @checkargs(min=2)
     def compile_with_expression(self, expr):
-        expr.pop(0)  # with
+        expr.pop(0)  # with*
 
         args = expr.pop(0)
-        if len(args) > 2 or len(args) < 1:
+        if not isinstance(args, HyList):
-            raise HyTypeError(expr, "with needs [arg (expr)] or [(expr)]")
+            raise HyTypeError(expr,
+                              "with expects a list, received `{0}'".format(
+                                  type(args).__name__))
+        if len(args) < 1:
+            raise HyTypeError(expr, "with needs [[arg (expr)]] or [[(expr)]]]")
 
         args.reverse()
         ctx = self.compile(args.pop(0))
@@ -1623,23 +1627,36 @@ class HyASTCompiler(object):
         result += ld_name
         return result
 
-    @builds("foreach")
+    @builds("for*")
     @checkargs(min=1)
     def compile_for_expression(self, expression):
         expression.pop(0)  # for
-        target_name, iterable = expression.pop(0)
+
+        args = expression.pop(0)
+
+        if not isinstance(args, HyList):
+            raise HyTypeError(expression,
+                              "for expects a list, received `{0}'".format(
+                                  type(args).__name__))
+
+        try:
+            target_name, iterable = args
+        except ValueError:
+            raise HyTypeError(expression,
+                              "for requires two forms in the list")
+
         target = self._storeize(self.compile(target_name))
 
         ret = Result()
 
         orel = Result()
-        # (foreach [] body (else …))
+        # (for* [] body (else …))
         if expression and expression[-1][0] == HySymbol("else"):
             else_expr = expression.pop()
             if len(else_expr) > 2:
                 raise HyTypeError(
                     else_expr,
-                    "`else' statement in `foreach' is too long")
+                    "`else' statement in `for' is too long")
             elif len(else_expr) == 2:
                 orel += self.compile(else_expr[1])
                 orel += orel.expr_as_stmt()

hy/contrib/anaphoric.hy

@@ -31,14 +31,14 @@
 
 (defmacro ap-each [lst &rest body]
   "Evaluate the body form for each element in the list."
-  `(foreach [it ~lst] ~@body))
+  `(for [[it ~lst]] ~@body))
 
 
 (defmacro ap-each-while [lst form &rest body]
   "Evalutate the body form for each element in the list while the
   predicate form evaluates to True."
   `(let [[p (lambda [it] ~form)]]
-     (foreach [it ~lst]
+     (for [[it ~lst]]
        (if (p it)
          ~@body
          (break)))))
@@ -47,7 +47,7 @@
 (defmacro ap-map [form lst]
   "Yield elements evaluated in the form for each element in the list."
   `(let [[f (lambda [it] ~form)]]
-     (foreach [v ~lst]
+     (for [[v ~lst]]
        (yield (f v)))))
 
 
@@ -55,7 +55,7 @@
   "Yield elements evaluated for each element in the list when the
   predicate function returns True."
   `(let [[f (lambda [it] ~rep)]]
-     (foreach [it ~lst]
+     (for [[it ~lst]]
        (if (~predfn it)
          (yield (f it))
          (yield it)))))
@@ -64,7 +64,7 @@
 (defmacro ap-filter [form lst]
   "Yield elements returned when the predicate form evaluates to True."
   `(let [[pred (lambda [it] ~form)]]
-     (foreach [val ~lst]
+     (for [[val ~lst]]
        (if (pred val)
          (yield val)))))
 

hy/core/bootstrap.hy

@@ -34,7 +34,7 @@
 (defmacro defmacro-alias [names lambda-list &rest body]
   "define one macro with several names"
   (setv ret `(do))
-  (foreach [name names]
+  (for* [name names]
     (.append ret
              `(defmacro ~name ~lambda-list ~@body)))
   ret)
@@ -52,7 +52,7 @@
   (setv macroed_variables [])
   (if (not (isinstance variables HyList))
     (macro-error variables "let lexical context must be a list"))
-  (foreach [variable variables]
+  (for* [variable variables]
     (if (isinstance variable HyList)
       (do
        (if (!= (len variable) 2)

hy/core/language.hy

@@ -33,11 +33,11 @@
 (defn cycle [coll]
   "Yield an infinite repetition of the items in coll"
   (setv seen [])
-  (foreach [x coll]
+  (for* [x coll]
     (yield x)
     (.append seen x))
   (while seen
-    (foreach [x seen]
+    (for* [x seen]
       (yield x))))
 
 (defn dec [n]
@@ -49,7 +49,7 @@
   "Return a generator from the original collection with duplicates
    removed"
   (let [[seen []] [citer (iter coll)]]
-    (foreach [val citer]
+    (for* [val citer]
       (if (not_in val seen)
         (do
          (yield val)
@@ -58,7 +58,7 @@
 (defn drop [count coll]
   "Drop `count` elements from `coll` and yield back the rest"
   (let [[citer (iter coll)]]
-    (try (foreach [i (range count)]
+    (try (for* [i (range count)]
            (next citer))
          (catch [StopIteration]))
     citer))
@@ -66,10 +66,10 @@
 (defn drop-while [pred coll]
   "Drop all elements of `coll` until `pred` is False"
   (let [[citer (iter coll)]]
-    (foreach [val citer]
+    (for* [val citer]
       (if (not (pred val))
         (do (yield val) (break))))
-    (foreach [val citer]
+    (for* [val citer]
       (yield val))))
 
 (defn empty? [coll]
@@ -84,7 +84,7 @@
 (defn filter [pred coll]
   "Return all elements from `coll` that pass `pred`"
   (let [[citer (iter coll)]]
-    (foreach [val citer]
+    (for* [val citer]
       (if (pred val)
         (yield val)))))
 
@@ -96,7 +96,7 @@
 
 (defn _flatten [coll result]
   (if (and (iterable? coll) (not (string? coll)))
-    (do (foreach [b coll]
+    (do (for* [b coll]
           (_flatten b result)))
     (.append result coll))
   result)
@@ -187,7 +187,7 @@
 (defn remove [pred coll]
   "Return coll with elements removed that pass `pred`"
   (let [[citer (iter coll)]]
-    (foreach [val citer]
+    (for* [val citer]
       (if (not (pred val))
         (yield val)))))
 
@@ -195,7 +195,7 @@
   "Yield x forever or optionally n times"
   (if (none? n)
     (setv dispatch (fn [] (while true (yield x))))
-    (setv dispatch (fn [] (foreach [_ (range n)] (yield x)))))
+    (setv dispatch (fn [] (for* [_ (range n)] (yield x)))))
   (dispatch))
 
 (defn repeatedly [func]
@@ -223,7 +223,7 @@
   "Take `count` elements from `coll`, or the whole set if the total
     number of entries in `coll` is less than `count`."
   (let [[citer (iter coll)]]
-    (foreach [_ (range count)]
+    (for* [_ (range count)]
       (yield (next citer)))))
 
 (defn take-nth [n coll]
@@ -231,16 +231,16 @@
      raises ValueError for (not (pos? n))"
   (if (pos? n)
     (let [[citer (iter coll)] [skip (dec n)]]
-      (foreach [val citer]
+      (for* [val citer]
         (yield val)
-        (foreach [_ (range skip)]
+        (for* [_ (range skip)]
           (next citer))))
     (raise (ValueError "n must be positive"))))
 
 (defn take-while [pred coll]
   "Take all elements while `pred` is true"
   (let [[citer (iter coll)]]
-    (foreach [val citer]
+    (for* [val citer]
       (if (pred val)
         (yield val)
         (break)))))

hy/core/macros.hy

@@ -26,17 +26,24 @@
 ;;; They are automatically required in every module, except inside hy.core
 
 (defmacro for [args &rest body]
-  "shorthand for nested foreach loops:
+  "shorthand for nested for loops:
-  (for [x foo y bar] baz) ->
+  (for [[x foo] [y bar]] baz) ->
-  (foreach [x foo]
+  (for* [x foo]
-    (foreach [y bar]
+    (for* [y bar]
       baz))"
-  ;; TODO: that signature sucks.
-  ;; (for [[x foo] [y bar]] baz) would be more consistent
-  (if (% (len args) 2)
-    (macro-error args "for needs an even number of elements in its first argument"))
   (if args
-    `(foreach [~(.pop args 0) ~(.pop args 0)] (for ~args ~@body))
+    `(for* ~(.pop args 0) (for ~args ~@body))
+    `(do ~@body)))
+
+
+(defmacro with [args &rest body]
+  "shorthand for nested for* loops:
+  (with [[x foo] [y bar]] baz) ->
+  (with* [x foo]
+    (with* [y bar]
+      baz))"
+  (if args
+    `(with* ~(.pop args 0) (with ~args ~@body))
     `(do ~@body)))
 
 
@@ -71,7 +78,7 @@
   (setv root (check-branch branch))
   (setv latest-branch root)
 
-  (foreach [branch branches]
+  (for* [branch branches]
     (setv cur-branch (check-branch branch))
     (.append latest-branch cur-branch)
     (setv latest-branch cur-branch))
@@ -81,7 +88,7 @@
 (defmacro -> [head &rest rest]
   ;; TODO: fix the docstring by someone who understands this
   (setv ret head)
-  (foreach [node rest]
+  (for* [node rest]
     (if (not (isinstance node HyExpression))
       (setv node `(~node)))
     (.insert node 1 ret)
@@ -92,7 +99,7 @@
 (defmacro ->> [head &rest rest]
   ;; TODO: fix the docstring by someone who understands this
   (setv ret head)
-  (foreach [node rest]
+  (for* [node rest]
     (if (not (isinstance node HyExpression))
       (setv node `(~node)))
     (.append node ret)
@@ -113,7 +120,7 @@
 (defmacro yield-from [iterable]
   "Yield all the items from iterable"
   (let [[x (gensym)]]
-  `(foreach [~x ~iterable]
+  `(for* [~x ~iterable]
      (yield ~x))))
 
 (defmacro with-gensyms [args &rest body]

tests/__init__.py

@@ -12,4 +12,5 @@ from .native_tests.when import *  # noqa
 from .native_tests.with_decorator import *  # noqa
 from .native_tests.core import *  # noqa
 from .native_tests.reader_macros import *  # noqa
+from .native_tests.with_test import *  # noqa
 from .native_tests.contrib.anaphoric import *  # noqa

tests/compilers/test_ast.py

@@ -295,9 +295,9 @@ def test_ast_bad_assoc():
 
 def test_ast_bad_with():
     "Make sure AST can't compile invalid with"
-    cant_compile("(with)")
+    cant_compile("(with*)")
-    cant_compile("(with [])")
+    cant_compile("(with* [])")
-    cant_compile("(with [] (pass))")
+    cant_compile("(with* [] (pass))")
 
 
 def test_ast_valid_while():
@@ -305,14 +305,14 @@ def test_ast_valid_while():
     can_compile("(while foo bar)")
 
 
-def test_ast_valid_foreach():
+def test_ast_valid_for():
-    "Make sure AST can compile valid foreach"
+    "Make sure AST can compile valid for"
-    can_compile("(foreach [a 2])")
+    can_compile("(for [[a 2]])")
 
 
-def test_ast_invalid_foreach():
+def test_ast_invalid_for():
-    "Make sure AST can't compile invalid foreach"
+    "Make sure AST can't compile invalid for"
-    cant_compile("(foreach [a 1] (else 1 2))")
+    cant_compile("(for* [a 1] (else 1 2))")
 
 
 def test_ast_expression_basics():

tests/native_tests/language.hy

@@ -31,12 +31,12 @@
 (defn test-for-loop []
   "NATIVE: test for loops?"
   (setv count 0)
-  (for [x [1 2 3 4 5]]
+  (for [[x [1 2 3 4 5]]]
     (setv count (+ count x)))
   (assert (= count 15))
   (setv count 0)
-  (for [x [1 2 3 4 5]
+  (for [[x [1 2 3 4 5]]
-        y [1 2 3 4 5]]
+        [y [1 2 3 4 5]]]
     (setv count (+ count x y)))
   (assert (= count 150)))
 
@@ -394,9 +394,9 @@
 
 (defn test-yield []
   "NATIVE: test yielding"
-  (defn gen [] (for [x [1 2 3 4]] (yield x)))
+  (defn gen [] (for [[x [1 2 3 4]]] (yield x)))
   (setv ret 0)
-  (for [y (gen)] (setv ret (+ ret y)))
+  (for [[y (gen)]] (setv ret (+ ret y)))
   (assert (= ret 10)))
 
 
@@ -439,37 +439,37 @@
 
 (defn test-context []
   "NATIVE: test with"
-  (with [fd (open "README.md" "r")] (assert fd))
+  (with [[fd (open "README.md" "r")]] (assert fd))
-  (with [(open "README.md" "r")] (do)))
+  (with [[(open "README.md" "r")]] (do)))
 
 
 (defn test-with-return []
   "NATIVE: test that with returns stuff"
   (defn read-file [filename]
-    (with [fd (open filename "r")] (.read fd)))
+    (with [[fd (open filename "r")]] (.read fd)))
   (assert (!= 0 (len (read-file "README.md")))))
 
 
 (defn test-for-doodle []
   "NATIVE: test for-do"
   (do (do (do (do (do (do (do (do (do (setv (, x y) (, 0 0)))))))))))
-  (foreach [- [1 2]]
+  (for [[- [1 2]]]
     (do
      (setv x (+ x 1))
      (setv y (+ y 1))))
   (assert (= y x 2)))
 
 
-(defn test-foreach-else []
+(defn test-for-else []
-  "NATIVE: test foreach else"
+  "NATIVE: test for else"
   (let [[x 0]]
-    (foreach [a [1 2]]
+    (for* [a [1 2]]
       (setv x (+ x a))
       (else (setv x (+ x 50))))
     (assert (= x 53)))
 
   (let [[x 0]]
-    (foreach [a [1 2]]
+    (for* [a [1 2]]
       (setv x (+ x a))
       (else))
     (assert (= x 3))))
@@ -636,7 +636,7 @@
 
 (defn test-nested-if []
   "NATIVE: test nested if"
-  (for [x (range 10)]
+  (for [[x (range 10)]]
     (if (in "foo" "foobar")
       (do
        (if true true true))
@@ -800,14 +800,14 @@
 
 (defn test-break-breaking []
   "NATIVE: test checking if break actually breaks"
-  (defn holy-grail [] (for [x (range 10)] (if (= x 5) (break))) x)
+  (defn holy-grail [] (for [[x (range 10)]] (if (= x 5) (break))) x)
   (assert (= (holy-grail) 5)))
 
 
 (defn test-continue-continuation []
   "NATIVE: test checking if continue actually continues"
   (setv y [])
-  (for [x (range 10)]
+  (for [[x (range 10)]] 
     (if (!= x 5) 
       (continue)) 
     (.append y x))

tests/native_tests/native_macros.hy

@@ -56,7 +56,7 @@
 (defn test-midtree-yield-in-for []
   "NATIVE: test yielding in a for with a return"
   (defn kruft-in-for []
-    (for [i (range 5)]
+    (for* [i (range 5)]
       (yield i))
     (+ 1 2)))
 
@@ -72,7 +72,7 @@
 (defn test-multi-yield []
   "NATIVE: testing multiple yields"
   (defn multi-yield []
-    (for [i (range 3)]
+    (for* [i (range 3)]
       (yield i))
     (yield "a")
     (yield "end"))
@@ -97,7 +97,7 @@
 (defn test-yield-from []
   "NATIVE: testing yield from"
   (defn yield-from-test []
-    (for [i (range 3)]
+    (for* [i (range 3)]
       (yield i))
     (yield-from [1 2 3]))
   (assert (= (list (yield-from-test)) [0 1 2 1 2 3])))

tests/native_tests/with_test.hy

@@ -0,0 +1,44 @@
+(defclass WithTest [object]
+  [(--init-- 
+    (fn [self val]
+      (setv self.val val)
+      None))
+
+  (--enter--
+    (fn [self]
+      self.val))
+
+  (--exit--
+    (fn [self type value traceback]
+      (setv self.val None)))])
+
+(defn test-single-with []
+  "NATIVE: test a single with"
+  (with [[t (WithTest 1)]]
+    (assert (= t 1))))
+
+(defn test-two-with []
+  "NATIVE: test two withs"
+  (with [[t1 (WithTest 1)]
+         [t2 (WithTest 2)]]
+   (assert (= t1 1))
+   (assert (= t2 2))))
+
+(defn test-thrice-with []
+  "NATIVE: test three withs"
+  (with [[t1 (WithTest 1)]
+         [t2 (WithTest 2)]
+         [t3 (WithTest 3)]]
+    (assert (= t1 1))
+    (assert (= t2 2))
+    (assert (= t3 3))))
+
+(defn test-quince-with []
+  "NATIVE: test four withs, one with no args"
+    (with [[t1 (WithTest 1)]
+          [t2 (WithTest 2)]
+          [t3 (WithTest 3)]
+          [(WithTest 4)]]
+    (assert (= t1 1))
+    (assert (= t2 2))
+    (assert (= t3 3))))