Draft: C Interfacing

This MR enables C compatibility for the generated target code

• Adds SfgConfig.c_interfacing option that automatically marks all function declarations as extern "C"
• Provides hybrid compilation mode for header files where C/C++ includes and also function definitions are guarded by

#ifdef __cplusplus 
<cpp includes...>

#define EXTERNC extern "C"
#else 
<hybrid includes...>

#define EXTERN C
#endif

• Automatically converts C++ header includes, e.g. <cstdint>, to C compatible header includes, e.g. <stdint.h>, for hybrid mode

src/pystencilssfg/composer/basic_composer.py

@@ -15,6 +15,7 @@ from pystencils import (
 )
 from pystencils.codegen import Kernel, Lambda
 from pystencils.types import create_type, UserTypeSpec, PsType
+from pystencilssfg.ir import SfgSourceFileType
 
 from ..context import SfgContext, SfgCursor
 from .custom import CustomGenerator
@@ -383,6 +384,8 @@ class SfgBasicComposer(SfgIComposer):
 
         if self._ctx.impl_file is None:
             seq.inline()
+        if self._ctx.c_interfacing:
+            seq._externC = True
 
         return seq
 
@@ -661,6 +664,7 @@ class SfgFunctionSequencerBase:
 
         #   Qualifiers
         self._inline: bool = False
+        self._externC: bool = False
         self._constexpr: bool = False
 
         #   Attributes
@@ -702,6 +706,10 @@ class SfgFunctionSequencer(SfgFunctionSequencerBase):
     """Sequencer for constructing functions."""
 
     def __call__(self, *args: SequencerArg) -> None:
+        # check if header is in HYBRID mode for c_interfacing enabled
+        if self._cursor.context.c_interfacing:
+            assert self._cursor.context.header_file.file_type == SfgSourceFileType.HYBRID_HEADER
+
         """Populate the function body"""
         tree = make_sequence(*args)
         func = SfgFunction(
@@ -710,6 +718,7 @@ class SfgFunctionSequencer(SfgFunctionSequencerBase):
             tree,
             return_type=self._return_type,
             inline=self._inline,
+            externC=self._externC,
             constexpr=self._constexpr,
             attributes=self._attributes,
             required_params=self._params,