implement'language='c++' option for cythonize()

CHANGES.rst

@@ -8,6 +8,10 @@ Latest
 Features added
 --------------
 
+* Passing ``language='c++'`` into cythonize() globally enables C++ mode for
+  all modules that were not passed as Extension objects (i.e. only source
+  files and file patterns).
+
 * ``Py_hash_t`` is a known type (used in CPython for hash values).
 
 * ``PySlice_*()`` C-API functions are available from the ``cpython.slice``

Cython/Build/Dependencies.py

@@ -586,7 +586,8 @@ def create_dependency_tree(ctx=None, quiet=False):
 
 
 # This may be useful for advanced users?
-def create_extension_list(patterns, exclude=[], ctx=None, aliases=None, quiet=False, exclude_failures=False):
+def create_extension_list(patterns, exclude=[], ctx=None, aliases=None, quiet=False, language=None,
+                          exclude_failures=False):
     if not isinstance(patterns, (list, tuple)):
         patterns = [patterns]
     explicit_modules = set([m.name for m in patterns if isinstance(m, Extension)])
@@ -606,6 +607,7 @@ def create_extension_list(patterns, exclude=[], ctx=None, aliases=None, quiet=Fa
             name = '*'
             base = None
             exn_type = Extension
+            ext_language = language
         elif isinstance(pattern, Extension):
             for filepattern in pattern.sources:
                 if os.path.splitext(filepattern)[1] in ('.py', '.pyx'):
@@ -618,6 +620,7 @@ def create_extension_list(patterns, exclude=[], ctx=None, aliases=None, quiet=Fa
             name = template.name
             base = DistutilsInfo(exn=template)
             exn_type = template.__class__
+            ext_language = None  # do not override whatever the Extension says
         else:
             raise TypeError(pattern)
 
@@ -661,6 +664,9 @@ def create_extension_list(patterns, exclude=[], ctx=None, aliases=None, quiet=Fa
                         depends = list(set(template.depends).union(set(depends)))
                     kwds['depends'] = depends
 
+                if ext_language and 'language' not in kwds:
+                    kwds['language'] = ext_language
+
                 module_list.append(exn_type(
                         name=module_name,
                         sources=sources,
@@ -671,7 +677,7 @@ def create_extension_list(patterns, exclude=[], ctx=None, aliases=None, quiet=Fa
 
 
 # This is the user-exposed entry point.
-def cythonize(module_list, exclude=[], nthreads=0, aliases=None, quiet=False, force=False,
+def cythonize(module_list, exclude=[], nthreads=0, aliases=None, quiet=False, force=False, language=None,
               exclude_failures=False, **options):
     """
     Compile a set of source modules into C/C++ files and return a list of distutils
@@ -684,6 +690,11 @@ def cythonize(module_list, exclude=[], nthreads=0, aliases=None, quiet=False, fo
     When using glob patterns, you can exclude certain module names explicitly
     by passing them into the 'exclude' option.
 
+    To globally enable C++ mode, you can pass language='c++'.  Otherwise, this
+    will be determined at a per-file level based on compiler directives.  This
+    affects only modules found based on file names.  Extension instances passed
+    into cythonize() will not be changed.
+
     For parallel compilation, set the 'nthreads' option to the number of
     concurrent builds.
 
@@ -711,6 +722,7 @@ def cythonize(module_list, exclude=[], nthreads=0, aliases=None, quiet=False, fo
         ctx=ctx,
         quiet=quiet,
         exclude_failures=exclude_failures,
+        language=language,
         aliases=aliases)
     deps = create_dependency_tree(ctx, quiet=quiet)
     build_dir = getattr(options, 'build_dir', None)

docs/src/userguide/wrapping_CPlusPlus.rst

@@ -137,10 +137,14 @@ together into :file:`rect.so`, which you can then import in Python using
 ``import rect`` (if you forget to link the :file:`Rectangle.o`, you will
 get missing symbols while importing the library in Python).
 
+Note that the ``language`` option has no effect on user provided Extension
+objects that are passed into ``cythonize()``.  It is only used for modules
+found by file name (as in the example above).
+
 The options can also be passed directly from the source file, which is
-often preferable.  Starting with version 0.17, Cython also allows to
-pass external source files into the ``cythonize()`` command this way.
-Here is a simplified setup.py file::
+often preferable (and overrides any global option).  Starting with
+version 0.17, Cython also allows to pass external source files into the
+``cythonize()`` command this way.  Here is a simplified setup.py file::
 
    from distutils.core import setup
    from Cython.Build import cythonize

tests/build/cpp_cythonize.srctree

@@ -10,13 +10,11 @@ from Cython.Build.Dependencies import cythonize
 from distutils.core import setup
 
 setup(
-  ext_modules = cythonize("*.pyx"),
+    ext_modules = cythonize("*.pyx", language='c++'),
 )
 
 ######## a.pyx ########
 
-# distutils: language = c++
-
 from libcpp.vector cimport vector
 
 def use_vector(L):