mkd_callbacks — functions that modify link targets
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(*mkd_callback_t)(const char*, const int, void*);
(*mkd_free_t)(char *, void*);
mkd_e_url(MMIOT *document, mkd_callback_t edit);
mkd_e_flags(MMIOT *document, mkd_callback_t edit);
mkd_e_free(MMIOT *document, mkd_free_t dealloc);
mkd_e_data(MMIOT *document, void *data);
Discount provides a small set of data access functions to let a library user modify the targets given in a ‘’ link, and to add additional flags to the generated link.
The data access functions are passed a character pointer to the url being generated, the size of the url, and a data pointer pointing to a user data area (set by the mkd_e_data() function.) After the callback function is called (either mkd_e_url() or mkd_e_flags()) the data freeing function (if supplied) is called and passed the character pointer and user data pointer.
The mkd_basename() function (in the module basename.c) is implemented by means of mkd callbacks; it modifies urls that start with a ‘/’ so that they begin with a user-supplied url base by allocating a new string and filling it with the base + the url. Discount plugs that url in in place of the original, then calls the basename free function (it only does this when mkd_e_url() or mkd_e_flags() returns nonzero) to deallocate this memory.
Note that only one level of callbacks are supported; if you wish to do multiple callbacks, you need to write your own code to handle them all.
Error handling is minimal at best.
Mastodon January 18, 2008 Mastodon