Fixed kernel_decorator with config parameter

The current kernel decorator does not work properly with the introduced CreateKernelConfig.

This MR fixes that.

pystencils/kernel_decorator.py

@@ -7,11 +7,12 @@ import sympy as sp
 
 from pystencils.assignment import Assignment
 from pystencils.sympyextensions import SymbolCreator
+from pystencils.kernelcreation import CreateKernelConfig
 
 __all__ = ['kernel']
 
 
-def kernel(func: Callable[..., None], return_config: bool = False, **kwargs) -> Union[List[Assignment], Dict]:
+def kernel(config: CreateKernelConfig = None, **kwargs) -> Callable[..., Union[List[Assignment], Dict]]:
     """Decorator to simplify generation of pystencils Assignments.
 
     Changes the meaning of the '@=' operator. Each line containing this operator gives a symbolic assignment
@@ -21,8 +22,8 @@ def kernel(func: Callable[..., None], return_config: bool = False, **kwargs) ->
     The decorated function may not receive any arguments, with exception of an argument called 's' that specifies
     a SymbolCreator()
     func: the decorated function
-    return_config: Specify whether to return the list with assignments, or a dictionary containing additional settings
-                   like func_name
+    config: Specify whether to return the list with assignments, or a dictionary containing additional settings
+            like func_name
 
     Examples:
         >>> import pystencils as ps
@@ -34,31 +35,34 @@ def kernel(func: Callable[..., None], return_config: bool = False, **kwargs) ->
         >>> f, g = ps.fields('f, g: [2D]')
         >>> assert my_kernel[0].rhs == f[0,1] + f[1,0]
     """
-    source = inspect.getsource(func)
-    source = textwrap.dedent(source)
-    a = ast.parse(source)
-    KernelFunctionRewrite().visit(a)
-    ast.fix_missing_locations(a)
-    gl = func.__globals__.copy()
-
-    assignments = []
-
-    def assignment_adder(lhs, rhs):
-        assignments.append(Assignment(lhs, rhs))
-
-    gl['_add_assignment'] = assignment_adder
-    gl['_Piecewise'] = sp.Piecewise
-    gl.update(inspect.getclosurevars(func).nonlocals)
-    exec(compile(a, filename="<ast>", mode="exec"), gl)
-    func = gl[func.__name__]
-    args = inspect.getfullargspec(func).args
-    if 's' in args and 's' not in kwargs:
-        kwargs['s'] = SymbolCreator()
-    func(**kwargs)
-    if return_config:
-        return {'assignments': assignments, 'function_name': func.__name__}
-    else:
-        return assignments
+    def decorator(func: Callable[..., None]) -> Union[List[Assignment], Dict]:
+        source = inspect.getsource(func)
+        source = textwrap.dedent(source)
+        a = ast.parse(source)
+        KernelFunctionRewrite().visit(a)
+        ast.fix_missing_locations(a)
+        gl = func.__globals__.copy()
+
+        assignments = []
+
+        def assignment_adder(lhs, rhs):
+            assignments.append(Assignment(lhs, rhs))
+
+        gl['_add_assignment'] = assignment_adder
+        gl['_Piecewise'] = sp.Piecewise
+        gl.update(inspect.getclosurevars(func).nonlocals)
+        exec(compile(a, filename="<ast>", mode="exec"), gl)
+        func = gl[func.__name__]
+        args = inspect.getfullargspec(func).args
+        if 's' in args and 's' not in kwargs:
+            kwargs['s'] = SymbolCreator()
+        func(**kwargs)
+        if config:
+            config.function_name = func.__name__
+            return {'assignments': assignments, 'config': config}
+        else:
+            return assignments
+    return decorator
 
 
 # noinspection PyMethodMayBeStatic