Add example of a Python wrapper which uses libcmark-gfmextensions. (g…

…ithub#102)

wrappers/wrapper_ext.py

@@ -0,0 +1,109 @@
+#!/usr/bin/env python
+
+#
+# Example for using the shared library from python.
+# Will work with either python 2 or python 3.
+# Requires cmark-gfm and cmark-gfmextensions libraries to be installed.
+#
+# This particular example uses the GitHub extensions from the gfmextensions
+# library. EXTENSIONS specifies which to use, and the sample shows how to
+# connect them into a parser.
+#
+
+import sys
+import ctypes
+
+if sys.platform == 'darwin':
+    libname = 'libcmark-gfm.dylib'
+    extname = 'libcmark-gfmextensions.dylib'
+elif sys.platform == 'win32':
+    libname = 'cmark-gfm.dll'
+    extname = 'cmark-gfmextensions.dll'
+else:
+    libname = 'libcmark-gfm.so'
+    extname = 'libcmark-gfmextensions.so'
+cmark = ctypes.CDLL(libname)
+cmark_ext = ctypes.CDLL(extname)
+
+# Options for the GFM rendering call
+OPTS = 0  # defaults
+
+# The GFM extensions that we want to use
+EXTENSIONS = (
+  'autolink',
+  'table',
+  'strikethrough',
+  'tagfilter',
+  )
+
+# Use ctypes to access the functions in libcmark-gfm
+
+F_cmark_parser_new = cmark.cmark_parser_new
+F_cmark_parser_new.restype = ctypes.c_void_p
+F_cmark_parser_new.argtypes = (ctypes.c_int,)
+
+F_cmark_parser_feed = cmark.cmark_parser_feed
+F_cmark_parser_feed.restype = None
+F_cmark_parser_feed.argtypes = (ctypes.c_void_p, ctypes.c_char_p, ctypes.c_size_t)
+
+F_cmark_parser_finish = cmark.cmark_parser_finish
+F_cmark_parser_finish.restype = ctypes.c_void_p
+F_cmark_parser_finish.argtypes = (ctypes.c_void_p,)
+
+F_cmark_parser_attach_syntax_extension = cmark.cmark_parser_attach_syntax_extension
+F_cmark_parser_attach_syntax_extension.restype = ctypes.c_int
+F_cmark_parser_attach_syntax_extension.argtypes = (ctypes.c_void_p, ctypes.c_void_p)
+
+F_cmark_parser_get_syntax_extensions = cmark.cmark_parser_get_syntax_extensions
+F_cmark_parser_get_syntax_extensions.restype = ctypes.c_void_p
+F_cmark_parser_get_syntax_extensions.argtypes = (ctypes.c_void_p,)
+
+F_cmark_parser_free = cmark.cmark_parser_free
+F_cmark_parser_free.restype = None
+F_cmark_parser_free.argtypes = (ctypes.c_void_p,)
+
+F_cmark_node_free = cmark.cmark_node_free
+F_cmark_node_free.restype = None
+F_cmark_node_free.argtypes = (ctypes.c_void_p,)
+
+F_cmark_find_syntax_extension = cmark.cmark_find_syntax_extension
+F_cmark_find_syntax_extension.restype = ctypes.c_void_p
+F_cmark_find_syntax_extension.argtypes = (ctypes.c_char_p,)
+
+F_cmark_render_html = cmark.cmark_render_html
+F_cmark_render_html.restype = ctypes.c_char_p
+F_cmark_render_html.argtypes = (ctypes.c_void_p, ctypes.c_int, ctypes.c_void_p)
+
+
+# Set up the libcmark-gfm library and its extensions
+F_register = cmark_ext.core_extensions_ensure_registered
+F_register.restype = None
+F_register.argtypes = ( )
+F_register()
+
+
+def md2html(text):
+  "Use cmark-gfm to render the Markdown into an HTML fragment."
+
+  parser = F_cmark_parser_new(OPTS)
+  assert parser
+  for name in EXTENSIONS:
+    ext = F_cmark_find_syntax_extension(name)
+    assert ext
+    rv = F_cmark_parser_attach_syntax_extension(parser, ext)
+    assert rv
+  exts = F_cmark_parser_get_syntax_extensions(parser)
+
+  F_cmark_parser_feed(parser, text, len(text))
+  doc = F_cmark_parser_finish(parser)
+  assert doc
+
+  output = F_cmark_render_html(doc, OPTS, exts)
+
+  F_cmark_parser_free(parser)
+  F_cmark_node_free(doc)
+
+  return output
+
+
+sys.stdout.write(md2html(sys.stdin.read()))