Rework COp to allow all methods to be defined.

doc/tutorial/extending_theano_c.txt

@@ -688,14 +688,13 @@ To help with this, Theano defines a class, ``COp``, from which new C ops
 can inherit. The class ``COp`` aims to simplify the process of implementing
 C ops by doing the following :
 
-*       It allows you to define the C implementation of your op in a distinct
-        C code file. This makes it easier to keep your Python and C code
-        readable and well indented.
+*      It allows you to define the C implementation of your op in a distinct
+       C code file. This makes it easier to keep your Python and C code
+       readable and well indented.
 
-*       It automatically handles the methods :meth:`Op.c_code()`,
-        :meth:`Op.c_support_code()`, :meth:`Op.c_support_code_apply()` and
-        :meth:`Op.c_code_cache_version()` based on the provided external C
-        implementation.
+*      It can automatically handle all the methods that return C code,
+       in addition to :meth:`Op.c_code_cache_version()` based on the
+       provided external C implementation.
 
 To illustrate how much simpler the class ``COp`` makes the process of defining
 a new op with a C implementation, let's revisit the second example of this
@@ -740,7 +739,7 @@ C file named vectorTimesVector.c :
 
 .. code-block:: c
 
-    THEANO_SUPPORT_CODE_SECTION
+    #section support_code
 
     // Support code function
     bool vector_same_shape(PyArrayObject* arr1, PyArrayObject* arr2)
@@ -749,7 +748,7 @@ C file named vectorTimesVector.c :
     }
 
 
-    THEANO_APPLY_CODE_SECTION
+    #section support_code_apply
 
     // Apply-specific support function
     void APPLY_SPECIFIC(vector_elemwise_mult)(
@@ -822,45 +821,44 @@ this new version of the VectorTimesVector op :
 *       Parent class : instead of inheriting from the class :class:`Op`,
         VectorTimesVector inherits from the class ``COp``.
 
-*       Constructor : in our new op, the ``__init__()`` method has an important
-        use; to inform the constructor of the ``COp`` class of the location,
-        on the filesystem of the C implementation of this op. To do this, it
-        gives the path of file containing the C code as well as the name of
-        the function, in that file, that should be called to perform the
-        computation. The path should be given as a relative path from the
-        folder where the descendant of the ``COp`` class is defined.
-
-*       ``make_node()`` : the ``make_node()`` method is absolutely identical to
-        the one in our old example. Using the ``COp`` class doesn't change
-        anything here.
-
-*       External C code : the external C code performs the computation
-        associated with the op. It contains, at the very least, a 'main' function
-        having the same name as provided to the constructor of the Python class
-        ``COp``. Writing this C code involves a few subtleties which deserve their
-        own respective sections.
-
+*       Constructor : in our new op, the ``__init__()`` method has an
+        important use; to inform the constructor of the ``COp`` class
+        of the location, on the filesystem of the C implementation of
+        this op. To do this, it gives a list of file paths containing
+        the C code for this op.  To auto-generate the c_code method
+        with a function call you can specify the function name as the
+        second parameter.  The paths should be given as a relative
+        path from the folder where the descendant of the ``COp`` class
+        is defined.
+
+*       ``make_node()`` : the ``make_node()`` method is absolutely
+        identical to the one in our old example. Using the ``COp``
+        class doesn't change anything here.
+
+*       External C code : the external C code implements the various
+        functions associated with the op.  associated with the op.
+        Writing this C code involves a few subtleties which deserve
+        their own respective sections.
 
 Main function
 -------------
 
-The external C implementation must implement a main function whose name
-is passed by the op to the ``__init__()`` method of the ``COp`` class. This
-main C function must respect the following constraints :
+If you pass a function name to the ``__init__()`` method of the ``COp`` class, it must respect the following constraints:
 
-*       It must return an int. The value of that int indicates whether the
-        op could perform its task or not. A value of 0 indicates success while
-        any non-zero value will interrupt the execution of the Theano function.
-        Before returning a non-zero integer, the main function should call the
-        function ``PyErr_Format()`` to setup a Python exception.
+*       It must return an int. The value of that int indicates whether
+        the op could perform its task or not. A value of 0 indicates
+        success while any non-zero value will interrupt the execution
+        of the Theano function.  When returning non-zero the function
+        must set a python exception indicating the details of the
+        problem.
 
-*       It must receive one pointer for each input to the op followed by one
-        pointer to a pointer for each output of the op.
+*       It must receive one argument for each input to the op followed by one
+        pointer to an argument for each output of the op.
 
-For example, the main C function of an op that takes two scalars as inputs and
-returns both their sum and the difference between them would have four
-parameters (two for the op's inputs and two for its outputs) and it's
-signature would look something like this :
+For example, the main C function of an op that takes two arrays as
+inputs and returns both their sum and the difference between them
+would have four parameters (two for the op's inputs and two for its
+outputs) and it's signature would look something like this :
 
 .. code-block:: c
 
@@ -870,11 +868,21 @@ signature would look something like this :
 Macros
 ------
 
-The ``COp`` class defines a number of macros that can you can use in your C
-implementation to make it simpler and more generic.
+For certain section tags, your C code can benefit from a number of
+pre-defined macros.  These section tags have no macros: ``init_code``,
+``c_support_code``. All other tags will have the support macros
+discussed below.
 
-For every input array 'i' (indexed from 0) of the op, the following macros are
-defined:
+*      ``APPLY_SPECIFIC(str)`` which will automatically append a name
+       unique to the :ref:`Apply node that applies the Op at the end
+       of the provided ``str``. The use of this macro is discussed
+       futher below.
+
+For every input which has a :attr:`dtype` attribute (this means
+Tensors, and equivalent types on GPU), the following macros will be
+defined unless your Op class has an :attr:`Op.check_input` attribute
+defined to False. In these descrptions 'i' refers to the position
+(indexed from 0) in the input array.
 
 *       ``DTYPE_INPUT_{i}`` : NumPy dtype of the data in the array.
         This is the variable type corresponding to the NumPy dtype, not the
@@ -889,71 +897,87 @@ defined:
 
 *       ``TYPENUM_INPUT_{i}`` : Typenum of the data in the array
 
-*       ``ITEMSIZE_INPUT_{i}`` : Size, in bytes, of the elements in the array.
+*       ``ITEMSIZE_INPUT_{i}`` : Size, in bytes, of the elements in
+        the array.
+
+In the same way, the macros ``DTYPE_OUTPUT_{i}``,
+``ITEMSIZE_OUTPUT_{i}`` and ``TYPENUM_OUTPUT_{i}`` are defined for
+every output 'i' of the op.
 
-In the same way, the macros ``DTYPE_OUTPUT_{i}``, ``ITEMSIZE_OUTPUT_{i}`` and
-``TYPENUM_OUTPUT_{i}``  are defined for every output 'i' of the op.
+In addition to these macros, the ``init_code_struct``, ``code``, and
+``code_cleanup`` also have the following macros:
+
+*     ``FAIL`` : Code to insert at error points.  A python exception
+      should be set prior to this code.  An invocation look like this:
+
+      .. code-block:: c
+
+        if (error) {
+	  // Set python exception
+	  FAIL
+        }
 
-The ``COp`` class also defines the macro ``APPLY_SPECIFIC(str)`` which will
-automatically append the name of the :ref:`Apply node that applies the Op at
-the end of the provided ``str``. The use of this macro is discussed below.
+      You can add a semicolon after the macro if it makes your editor
+      happy.
 
-You should be aware, however, that these macros are apply-specific. As such,
-any function that uses them is considered to contain apply-specific code.
+*     ``CONTEXT`` : Name of the context variable for this node.  (only
+      for Ops which have a context, which is discussed elsewhere)
 
+Finally the tag ``code`` and ``code_cleanup`` have macros to
+pass the inputs and output names.  These are name ``INPUT_{i}`` and
+``OUTPUT_{i}`` where `i` is the 0-based index position in the input
+and output arrays respectively.
 
 Support code
 ------------
 
-The file whose name is provided to the ``COp`` class is not constrained to
-contain only one function. It can in fact contain many functions, with every
-function but the main one acting as support code.
-
-When we defined the VectorTimesVector op without using the ``COp`` class, we
-had to make a distinction between two types of support_code : the support
-code that was apply-specific and the support code that wasn't.
-The apply-specific code was defined in the ` c_support_code_apply()`` method
-and the elements defined in that code (global variables and functions) had to
-include the name of the Apply node in their own names to avoid conflicts
-between the different versions of the apply-specific code. The code that
-wasn't apply-specific was simply defined in the ``c_support_code()`` method.
-
-When using the ``COp`` class, we still have to make the distinction between
-apply-specific and apply-agnostic support code but we express it differently
-in the code since it is all defined in the same external C file.
-These two types of support code should each be defined in their own section of
-the file, like in the example above. These sections should be delimited by the
-markers ``THEANO_SUPPORT_CODE_SECTION`` (to be put on its own line, at the
-beginning of the apply-agnostic support code section) and
-``THEANO_APPLY_CODE_SECTION`` (to be put on its own line at the beginning of
-the apply-specific code section). Moreover, just like in the previous examples
-of this tutorial, apply-specific functions and global variables need to
-include the name of the :ref:`Apply` node in their names. To achieve this,
-the macro ``APPLY_SPECIFIC(str)`` should be used when defining those elements
-as well as when referring to them. In the above example, this macro is used
-when defining the functions ``vector_elemwise_mult()`` and
+Certain section are limited in what you can place in them due to
+semantic and syntactic restrictions of the C++ language.  Most of
+these restrictions apply to the tags that end in ``_struct``.
+
+When we defined the VectorTimesVector op without using the ``COp``
+class, we had to make a distinction between two types of support_code
+: the support code that was apply-specific and the support code that
+wasn't. The apply-specific code was defined in the
+``c_support_code_apply()`` method and the elements defined in that
+code (global variables and functions) had to include the name of the
+Apply node in their own names to avoid conflicts between the different
+versions of the apply-specific code. The code that wasn't
+apply-specific was simply defined in the ``c_support_code()`` method.
+
+To make indentifiers that include the :ref:`Apply` node name use the
+``APPLY_SPECIFIC(str)`` macro. In the above example, this macro is
+used when defining the functions ``vector_elemwise_mult()`` and
 ``vector_times_vector()`` as well as when calling function
 ``vector_elemwise_mult()`` from inside ``vector_times_vector()``.
 
-:note:
-
-    The macro ``APPLY_SPECIFIC(str)`` should only ever be used for
-    apply-specific code. It should not be used for apply-agnostic code.
-
-The rules for knowing if a piece of code should be put in the apply-agnostic
-or the apply-specific support code section of the file are simple. If it uses
-any of the macros defined by the class ``COp`` then it is apply-specific and
-goes in the corresponding section. If it calls any apply-specific code then
-it is apply-specific. Otherwise, it is apply-agnostic and goes in the
-apply-agnostic support code section.
-
-In the above example, the ``function vector_same_shape()`` is apply-agnostic
-because it uses none of the macros defined by the class ``COp`` and it doesn't
-rely on any apply-specific code. The function ``vector_elemwise_mult()`` is
-apply-specific because it uses the macros defined by ``COp``. Finally, the
-function ``vector_times_vector()`` is apply-specific because it uses those
-same macros and also because it calls ``vector_elemwise_mult()`` which is an
-apply-specific function.
+When using the ``COp`` class, we still have to make the distinction
+between C code for each of the methods of a C class. These sections of
+code are separated by ``#section <tag>`` markers. The tag determines
+the name of the method this C code applies to with the rule that
+``<tag>`` applies to `c_<tag>`. Unknown tags are an error and will be
+reported. Duplicate tags will be merged together in the order the
+appear in the C files.
+
+The rules for knowing if where a piece of code should be put can be
+sometimes tricky.  The key thing to remember is that things that can
+be shared between instances of the op should be apply-agnostic and go
+into a section which does not end in ``_apply`` or ``_struct``.  The
+distinction of ``_apply`` and ``_struct`` mostly hinghes on how you
+want to manange the lifetime of the object.  Note that to use an
+apply-specific object, you have to be in a apply-specific section, so
+some portions of the code that might seem apply-agnostic may still be
+apply-specific because of the data they use (this does not include
+arguments).
+
+In the above example, the ``function vector_same_shape()`` is
+apply-agnostic because it uses none of the macros defined by the class
+``COp`` and it doesn't rely on any apply-specific code. The function
+``vector_elemwise_mult()`` is apply-specific because it uses the
+macros defined by ``COp``. Finally, the function
+``vector_times_vector()`` is apply-specific because it uses those same
+macros and also because it calls ``vector_elemwise_mult()`` which is
+an apply-specific function.
 
 Final Note
 ==========

theano/gof/op.py

@@ -17,6 +17,7 @@ import logging
 import numpy
 import os
 import sys
+import re
 import warnings
 
 import theano
@@ -973,6 +974,32 @@ int main( int argc, const char* argv[] )
                                                 compute_map, no_recycling)
 
 
+def simple_meth(tag):
+    def f(self):
+        if tag in self.code_sections:
+            return self.code_sections[tag]
+        else:
+            raise utils.MethodNotDefined(
+                'c_' + tag, type(self), type(self).__name__)
+    f.__name__ = 'c_' + tag
+    return f
+
+
+def apply_meth(tag):
+    def f(self, node, name):
+        if tag in self.code_sections:
+            code = self.code_sections[tag]
+
+            define_macros, undef_macros = self.get_c_macros(node, name)
+            return os.linesep.join([define_macros, code,
+                                    undef_macros])
+        else:
+            raise utils.MethodNotDefined(
+                'c_' + tag, type(self), type(self).__name__)
+    f.__name__ = 'c_' + tag
+    return f
+
+
 class COp(Op):
     """ Class to allow an op to have an external C implementation.
 
@@ -981,118 +1008,85 @@ class COp(Op):
     the C implementation and the name of the function, in that file, to call
     to perform the computations for the op.
     """
+    section_re = re.compile(r'^#section ([a-zA-Z0-9_]+)$', re.MULTILINE)
+    # This is the set of allowed markers
+    SECTIONS = set([
+            'init_code', 'init_code_apply', 'init_code_struct',
+            'support_code', 'support_code_apply', 'support_code_struct',
+            'cleanup_code_struct',
+            'code', 'code_cleanup'])
 
-    def __init__(self, func_file, func_name):
-
-        self.func_file = func_file
-        self.func_name = func_name
-
-        # Define the markers that can be used to delimit sections in the
-        # external C code
-        self.support_code_marker = "THEANO_SUPPORT_CODE_SECTION"
-        self.apply_code_marker = "THEANO_APPLY_CODE_SECTION"
-        self.c_code_markers = [self.support_code_marker,
-                               self.apply_code_marker]
+    @classmethod
+    def get_path(cls, f):
+        """
+        Convert a path relative to the location of the class file into
+        an aboslute path. Paths that are already absolute are passed
+        through unchanged.
+        """
+        if not os.path.isabs(f):
+            class_file = inspect.getfile(cls)
+            class_dir = os.path.dirname(class_file)
+            f = os.path.realpath(os.path.join(class_dir, f))
+        return f
 
-        # Load the external C code
-        try:
-            # Attempt to find the file self.func_file in the folder where the
-            # concrete type of the COp instance is defined
-
-            # Get the name of the folder where the concrete type of the COp is
-            # defined
-            path_concrete_type = inspect.getfile(self.__class__)
-            folder_concrete_type = os.path.dirname(path_concrete_type)
-
-            # Try to open the file from there
-            f = open(os.path.join(folder_concrete_type, self.func_file), "r")
-            self.func_code = f.read()
-            f.close()
-
-        except IOError:
-
-            # Add information to the exception message to inform the user
-            # on the locations in which the class COp will look for the
-            # specified file
-            message = ("The path to the external C implementation should "
-                       "be given as a relative path from the folder "
-                       "where the Op is defined. ")
-
-            # Can't update the exception's message by modifying e.args
-            # because IOErrors don't use their attribute args to generate
-            # their error message
-            e.strerror = message + e.strerror
-            raise e
-
-        # Separate the contents of the file in sections and validate that at
-        # lest one of the necessary code sections has been defined
-        self.code_sections = self.parse_external_c_code(self.func_code)
-
-        if sum([marker in self.code_sections.keys()
-               for marker in self.c_code_markers]) == 0:
-
-            raise(RuntimeError, "The provided C implementation does not "
-                  "define a support code section or a support code apply "
-                  "section.")
-
-    def parse_external_c_code(self, code):
-
-        # Obtain the positions of the C code markers used in the C code
-        positions = [(code.index(marker), marker)
-                     for marker in self.c_code_markers if marker in code]
-
-        # Go over the markers in their order of occurence and extract
-        # the C code they concern
-        positions.sort()
-        code_sections = {}
-
-        for i in range(len(positions)):
-
-            marker_start, marker = positions[i]
-
-            if i < len(positions) - 1:
-                # This is not the last section in the code : extract the code
-                # between the beginning of the current marker and the
-                # beginning of the next one.
-                next_marker_start = positions[i+1][0]
-                section = code[marker_start: next_marker_start]
-            else:
-                # This is the last section in the code : extract the remaining
-                # C code
-                section = code[marker_start:]
+    def __init__(self, func_files, func_name=None):
+        """
+        Sections are loaded from files in order with sections in later
+        files overriding sections in previous files.
+        """
+        if not isinstance(func_files, list):
+            func_files = [func_files]
 
-            cleaned_section = section.replace(marker, "")
-            code_sections[marker] = cleaned_section
+        self.func_files = [self.get_path(f) for f in func_files]
+        self.func_name = func_name
 
-        return code_sections
+        self.load_c_code()
+
+        if len(self.code_sections) == 0:
+            raise ValueError("No sections where defined in C files")
+
+        if self.func_name is not None:
+            if 'op_code' in self.code_sections:
+                # maybe a warning instead (and clearing the key)
+                raise ValueError('Cannot have an "op_code" section and '
+                                 'specify the func_name')
+            if 'op_code_cleanup' in self.code_sections:
+                # maybe a warning instead (and clearing the key)
+                raise ValueError('Cannot have an "op_code_cleanup" section '
+                                 'and specify the func_name')
+
+    def load_c_code(self):
+        self.func_codes = []
+        for func_file in self.func_files:
+            with open(func_file, 'r') as f:
+                self.func_codes.append(f.read())
+
+        self.code_sections = dict()
+        for i, code in enumerate(self.func_codes):
+            split = self.section_re.split(code)
+            if split[0].strip() != '':
+                raise ValueError('Stray code before first #section '
+                                 'statement (in file %s): %s' %
+                                 (self.func_files[i], split[0]))
+            n = 1
+            while n < len(split):
+                if split[n] not in self.SECTIONS:
+                    raise ValueError("Unknown section type (in file %s): %s" %
+                                     (self.fun_files[i], split[n]))
+                if split[n] not in self.code_sections:
+                    self.code_sections[split[n]] = ""
+                self.code_sections[split[n]] += split[n+1]
+                n += 2
 
     def c_code_cache_version(self):
-        return hash(self.func_code)
-
-    def c_support_code(self):
-
-        if self.support_code_marker in self.code_sections:
-            return self.code_sections[self.support_code_marker]
-        else:
-            raise utils.MethodNotDefined("c_support_code",
-                type(self), self.__class__.__name__)
-
-    def c_support_code_apply(self, node, name):
-
-        if self.apply_code_marker in self.code_sections:
-            apply_code = self.code_sections[self.apply_code_marker]
-
-            if hasattr(self, 'check_inputs') and self.check_inputs == False:
-                return apply_code
-            else:
-                define_macros, undef_macros = self.get_c_macros(node, name)
-                return os.linesep.join([define_macros, apply_code,
-                                        undef_macros])
-
-        else:
-            raise utils.MethodNotDefined("c_support_code_apply",
-                type(self), self.__class__.__name__)
+        return hash(tuple(self.func_codes))
 
+    c_init_code = simple_meth('init_code')
+    c_init_code_apply = apply_meth('init_code_apply')
+    c_support_code = simple_meth('support_code')
+    c_support_code_apply = apply_meth('support_code_apply')
+    c_support_code_struct = apply_meth('support_code_struct')
+    c_cleanup_code_struct = apply_meth('cleanup_code_struct')
 
     def format_c_function_args(self, inp, out):
         # Generate an string containing the arguments sent to the external C
@@ -1100,73 +1094,149 @@ class COp(Op):
         # "input0, input1, input2, &output0, &output1"
         return ", ".join(list(inp) + ["&%s" % o for o in out])
 
-    def get_c_macros(self, node, name):
+    def get_c_macros(self, node, name, check_input=None):
+        define_template = "#define %s %s"
+        undef_template = "#undef %s"
+        define_macros = []
+        undef_macros = []
+
+        if check_input is None:
+            check_input = getattr(self, 'check_input', True)
+
+        if check_input:
+            # Extract the various properties of the input and output variables
+            variables = node.inputs + node.outputs
+            variable_names = (["INPUT_%i" % i for i in range(len(node.inputs))] +
+                              ["OUTPUT_%i" % i for i in range(len(node.inputs))])
 
-        define_template = "#define %s %s" + os.linesep
-        undef_template = "#undef %s" + os.linesep
-        define_macros = ""
-        undef_macros = ""
+            # Generate dtype macros
+            for i, v in enumerate(variables):
+                if not hasattr(v, 'dtype'):
+                    continue
+                vname = variable_names[i]
 
-        # Extract the various properties of the input and output variables
-        variables = node.inputs + node.outputs
-        variable_names = (["INPUT_%i" % i for i in range(len(node.inputs))] +
-                          ["OUTPUT_%i" % i for i in range(len(node.inputs))])
-        variable_dtypes_names = [v.dtype for v in variables]
-        variable_dtypes = [numpy.dtype(d) for d in variable_dtypes_names]
-        variable_typenums = [d.num for d in variable_dtypes]
-        variable_itemsizes = [d.itemsize for d in variable_dtypes]
+                macro_name = "DTYPE_" + vname
+                macro_value = "npy_" + v.dtype
 
-        # Generate dtype macros
-        for i in range(len(variables)):
-            macro_name = "DTYPE_" + variable_names[i]
-            macro_value = "npy_" + variable_dtypes_names[i]
+                define_macros.append(define_template % (macro_name, macro_value))
+                undef_macros.append(undef_template % macro_name)
 
-            define_macros += define_template % (macro_name, macro_value)
-            undef_macros += undef_template % macro_name
+                d = numpy.dtype(v.dtype)
 
-        # Generate typenum macros
-        for i in range(len(variables)):
-            macro_name = "TYPENUM_" + variable_names[i]
-            macro_value = variable_typenums[i]
+                macro_name = "TYPENUM_" + vname
+                macro_value = d.num
 
-            define_macros += define_template % (macro_name, macro_value)
-            undef_macros += undef_template % macro_name
+                define_macros.append(define_template % (macro_name, macro_value))
+                undef_macros.append(undef_template % macro_name)
 
-        # Generate itemsize macros
-        for i in range(len(variables)):
-            macro_name = "ITEMSIZE_" + variable_names[i]
-            macro_value = variable_itemsizes[i]
+                macro_name = "ITEMSIZE_" + vname
+                macro_value = d.itemsize
 
-            define_macros += define_template % (macro_name, macro_value)
-            undef_macros += undef_template % macro_name
+                define_macros.append(define_template % (macro_name, macro_value))
+                undef_macros.append(undef_template % macro_name)
 
         # Generate a macro to mark code as being apply-specific
-        define_macros += define_template % ("APPLY_SPECIFIC(str)",
-                                            "str##_%s" % name)
-        undef_macros += undef_template % "APPLY_SPECIFIC"
+        define_macros.append(define_template % ("APPLY_SPECIFIC(str)",
+                                                "str##_%s" % name))
+        undef_macros.append(undef_template % "APPLY_SPECIFIC")
+
+        return os.linesep.join(define_macros), os.linesep.join(undef_macros)
+
+    def _lquote_macro(self, txt):
+        res = []
+        spl = txt.split('\n')
+        for l in spl[:-1]:
+            res.append(l + ' \\')
+        res.append(spl[-1])
+        return os.linesep.join(res)
+
+    def get_sub_macros(self, sub):
+        define_macros = []
+        undef_macros = []
+        define_macros.append("#define FAIL %s" %
+                            (self._lquote_macro(sub['fail']),))
+        undef_macros.append("#undef FAIL")
+        if 'context' in sub:
+            define_macros.append("#define CONTEXT %s" % (sub['context'],))
+            undef_macos.append("#undef CONTEXT")
+
+        return os.linesep.join(define_macros), os.linesep.join(undef_macros)
+
+    def get_io_macros(self, inputs, outputs):
+        define_macros = []
+        undef_macros = []
+
+        for i, inp in enumerate(inputs):
+            define_macros.append("#define INPUT_%d %s" (i, inp))
+            undef_macros.append("#undef INPUT_%d", (i,))
+
+        for i, out in enumerate(outputs):
+            define_macros.append("#define OUTPUT_%d %s" (i, inp))
+            undef_macros.append("#undef OUTPUT_%d", (i,))
+
+    def c_init_code_struct(self, node, name, sub):
+        if 'init_code_struct' in self.code_sections:
+            op_code = self.code_sections['init_code_struct']
+
+            def_macros, undef_macros = self.get_c_macros(node, name)
+            def_sub, undef_sub = self.get_sub_macros(sub)
+
+            return os.linesep.join([def_macros, def_sub,
+                                    op_code,
+                                    undef_sub, undef_macros])
+        else:
+            raise utils.MethodNotDefined(
+                'c_init_code_struct', type(self), type(self).__name__)
 
-        return define_macros, undef_macros
 
     def c_code(self, node, name, inp, out, sub):
+        if self.func_name is not None:
+            assert 'code' not in self.code_sections
+            func_name = self.func_name
+            func_args = self.format_c_function_args(inp, out)
+            fail = sub['fail']
+
+            define_macros, undef_macros = self.get_c_macros(node, name,
+                                                            check_input=False)
+
+            # Generate the C code
+            return """
+%(define_macros)s
+{
+  if (%(func_name)s(%(func_args)s) != 0) {
+    %(fail)s
+  }
+}
+%(undef_macros)s
+""" % dict(func_name=self.func_name, fail=sub['fail'],
+           func_args=self.format_c_function_args(inp, out),
+           define_macros=define_macros, undef_macros=undef_macros)
+        else:
+            if 'code' in self.code_sections:
+                op_code = self.code_sections['code']
 
-        func_name = self.func_name
-        func_args = self.format_c_function_args(inp, out)
-        fail = sub['fail']
-
-        # Generate the code to define/undefine the C macros
-        define_macros, undef_macros = self.get_c_macros(node, name)
-
-        # Generate the C code
-        c_code = """
-        %(define_macros)s
-        {
-            int result = %(func_name)s(%(func_args)s);
-            if (result != 0)
-            {
-                %(fail)s;
-            }
-        }
-        %(undef_macros)s
-        """ % locals()
+                def_macros, undef_macros = self.get_c_macros(node, name)
+                def_sub, undef_sub = self.get_sub_macros(sub)
+                def_io, undef_io = self.get_io_macros(inp, out)
 
-        return c_code
+                return os.linesep.join([def_macros, def_sub, def_io,
+                                        op_code,
+                                        undef_io, undef_sub, undef_macros])
+            else:
+                raise utils.MethodNotDefined(
+                    'c_code', type(self), type(self).__name__)
+
+    def c_code_cleanup(self, node, name, inputs, outputs, sub):
+        if 'code_cleanup' in self.code_sections:
+            op_code = self.code_sections['code_cleanup']
+
+            def_macros, undef_macros = self.get_c_macros(node, name)
+            def_sub, undef_sub = self.get_sub_macros(sub)
+            def_io, undef_io = self.get_io_macros(inp, out)
+
+            return os.linesep.join([def_macros, def_sub, def_io,
+                                    op_code,
+                                    undef_io, undef_sub, undef_macros])
+        else:
+            raise utils.MethodNotDefined(
+                'c_code_cleanup', type(self), type(self).__name__)