Mandate calling of cython.parallel.parallel

Cython/Compiler/Nodes.py

@@ -5736,7 +5736,7 @@ class ParallelNode(Node):
 
 class ParallelStatNode(StatNode, ParallelNode):
     """
-    Base class for 'with cython.parallel.parallel:' and 'for i in prange():'.
+    Base class for 'with cython.parallel.parallel():' and 'for i in prange():'.
 
     assignments     { Entry(var) : (var.pos, inplace_operator_or_None) }
                     assignments to variables in this parallel section
@@ -5920,7 +5920,7 @@ class ParallelStatNode(StatNode, ParallelNode):
 
 class ParallelWithBlockNode(ParallelStatNode):
     """
-    This node represents a 'with cython.parallel.parallel:' block
+    This node represents a 'with cython.parallel.parallel():' block
     """
 
     nogil_check = None

Cython/Compiler/ParseTreeTransforms.py

@@ -963,7 +963,7 @@ class ParallelRangeTransform(CythonTransform, SkipDeclarations):
     module node, set there by InterpretCompilerDirectives.
 
         x = cython.parallel.threadavailable()   -> ParallelThreadAvailableNode
-        with nogil, cython.parallel.parallel:   -> ParallelWithBlockNode
+        with nogil, cython.parallel.parallel(): -> ParallelWithBlockNode
             print cython.parallel.threadid()    -> ParallelThreadIdNode
             for i in cython.parallel.prange(...):  -> ParallelRangeNode
                 ...
@@ -1064,36 +1064,40 @@ class ParallelRangeTransform(CythonTransform, SkipDeclarations):
 
         parallel_directive_class = self.get_directive_class_node(node)
         if parallel_directive_class:
+            # Note: in case of a parallel() the body is set by
+            # visit_WithStatNode
             node = parallel_directive_class(node.pos, args=args, kwargs=kwargs)
 
         return node
 
     def visit_WithStatNode(self, node):
-        "Rewrite with cython.parallel() blocks"
-        self.visit(node.manager)
-
-        if self.parallel_directive:
-            parallel_directive_class = self.get_directive_class_node(node)
-            if not parallel_directive_class:
-                # There was an error, stop here and now
-                return None
+        "Rewrite with cython.parallel.parallel() blocks"
+        newnode = self.visit(node.manager)
 
+        if isinstance(newnode, Nodes.ParallelWithBlockNode):
             if self.state == 'parallel with':
                 error(node.manager.pos,
                       "Closely nested 'with parallel:' blocks are disallowed")
 
             self.state = 'parallel with'
-            self.visit(node.body)
+            body = self.visit(node.body)
             self.state = None
 
-            newnode = Nodes.ParallelWithBlockNode(node.pos, body=node.body)
+            newnode.body = body
+            return newnode
+        elif self.parallel_directive:
+            parallel_directive_class = self.get_directive_class_node(node)
 
-        else:
-            newnode = node
+            if not parallel_directive_class:
+                # There was an error, stop here and now
+                return None
 
-        self.visit(node.body)
+            if parallel_directive_class is Nodes.ParallelWithBlockNode:
+                error(node.pos, "The parallel directive must be called")
+                return None
 
-        return newnode
+        node.body = self.visit(node.body)
+        return node
 
     def visit_ForInStatNode(self, node):
         "Rewrite 'for i in cython.parallel.prange(...):'"
@@ -1149,7 +1153,7 @@ class ParallelRangeTransform(CythonTransform, SkipDeclarations):
     def visit(self, node):
         "Visit a node that may be None"
         if node is not None:
-            super(ParallelRangeTransform, self).visit(node)
+            return super(ParallelRangeTransform, self).visit(node)
 
 
 class WithTransform(CythonTransform, SkipDeclarations):

tests/errors/e_cython_parallel.pyx

@@ -14,16 +14,16 @@ prange(1, 2, 3, schedule='dynamic')
 
 cdef int i
 
-with nogil, cython.parallel.parallel:
+with nogil, cython.parallel.parallel():
     for i in prange(10, schedule='invalid_schedule'):
         pass
 
-with cython.parallel.parallel:
+with cython.parallel.parallel():
     print "hello world!"
 
 cdef int *x = NULL
 
-with nogil, cython.parallel.parallel:
+with nogil, cython.parallel.parallel():
     for j in prange(10):
         pass
 
@@ -33,7 +33,10 @@ with nogil, cython.parallel.parallel:
     for x in prange(10):
         pass
 
-    with cython.parallel.parallel:
+    with cython.parallel.parallel():
+        pass
+
+with nogil, cython.parallel.parallel:
     pass
 
 _ERRORS = u"""
@@ -44,9 +47,10 @@ e_cython_parallel.pyx:7:0: No such directive: cython.parallel.something
 e_cython_parallel.pyx:13:6: prange() can only be used as part of a for loop
 e_cython_parallel.pyx:13:6: prange() can only be used without the GIL
 e_cython_parallel.pyx:18:19: Invalid schedule argument to prange: invalid_schedule
-e_cython_parallel.pyx:21:5: The parallel section may only be used without the GIL
+c_cython_parallel.pyx:21:29: The parallel section may only be used without the GIL
 e_cython_parallel.pyx:27:10: target may not be a Python object as we don't have the GIL
 e_cython_parallel.pyx:30:9: Can only iterate over an iteration variable
 e_cython_parallel.pyx:33:10: Must be of numeric type, not int *
-e_cython_parallel.pyx:36:24: Closely nested 'with parallel:' blocks are disallowed
+e_cython_parallel.pyx:36:33: Closely nested 'with parallel:' blocks are disallowed
+e_cython_parallel.pyx:39:12: The parallel directive must be called
 """

tests/run/parallel.pyx

@@ -16,7 +16,7 @@ def test_parallel():
     if buf == NULL:
         raise MemoryError
 
-    with nogil, cython.parallel.parallel:
+    with nogil, cython.parallel.parallel():
         buf[threadid()] = threadid()
 
     for i in range(maxthreads):
@@ -24,4 +24,4 @@ def test_parallel():
 
     free(buf)
 
-include "sequential_parallel.pyx"
+#include "sequential_parallel.pyx"

tests/run/sequential_parallel.pyx

@@ -23,7 +23,7 @@ def test_prange():
     """
     cdef Py_ssize_t i, j, sum1 = 0, sum2 = 0
 
-    with nogil, cython.parallel.parallel:
+    with nogil, cython.parallel.parallel():
         for i in prange(10, schedule='dynamic'):
             sum1 += i
 
@@ -57,9 +57,9 @@ def test_propagation():
         for j in prange(10):
             sum1 += i
 
-    with nogil, cython.parallel.parallel:
+    with nogil, cython.parallel.parallel():
         for x in prange(10):
-            with cython.parallel.parallel:
+            with cython.parallel.parallel():
                 for y in prange(10):
                     sum2 += y