lowdown_nroff_rndrrender Markdown into roff

library “liblowdown”

#include <sys/queue.h>
#include <stdio.h>
#include <lowdown.h>

lowdown_nroff_rndr(struct lowdown_buf *out, struct lowdown_metaq *mq, void *arg, const struct lowdown_node *n);

Renders a node tree n created by lowdown_doc_parse(3) or lowdown_diff(3) using the roff renderer arg as returned by lowdown_nroff_new(3). The output is written into out, which must be initialised and freed by the caller.

If mq is not NULL, it is filled with any metadata as parsed. It must be initialised and its contents freed with lowdown_metaq_free(3).

The output consists of roff output using the ms or man macro packages.

Returns zero on failure to allocate memory, non-zero on success.

The following assumes the the string buf of length bsz consists of Markdown content.

struct lowdown_buf *out;
struct lowdown_doc *doc;
struct lowdown_node *n;
void *rndr;

if ((doc = lowdown_doc_new(NULL)) == NULL)
  err(1, NULL);
if ((n = lowdown_doc_parse(doc, NULL, buf, bsz)) == NULL)
  err(1, NULL);
if ((out = lowdown_buf_new(256)) == NULL)
  err(1, NULL);
if ((rndr = lowdown_nroff_new(NULL)) == NULL)
  err(1, NULL);
if (!lowdown_nroff_rndr(out, NULL, rndr, n))
  err(1, NULL);

fwrite(out->data, 1, out->size, stdout);


lowdown(3), lowdown_nroff_free(3), lowdown_nroff_new(3)

This uses both the original troff man macros for Version 7 AT&T UNIX, defined in man(7), and the man-ext groff extensions. Both are implemented in mandoc.

The troff ms macros are defined in groff_ms(7), with the mspdf groff extensions described in "Portable Document Format Publishing with GNU Troff" by Keith Marshall. Neither are implemented in mandoc.

February 8, 2021 OpenBSD 6.7