.\"	$Id: lowdown_nroff_new.3,v 1.10 2021/02/19 21:50:39 kristaps Exp $
.\"
.\" Copyright (c) 2017--2021 Kristaps Dzonsons <kristaps@bsd.lv>
.\"
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.Dd $Mdocdate: February 19 2021 $
.Dt LOWDOWN_NROFF_NEW 3
.Os
.Sh NAME
.Nm lowdown_nroff_new
.Nd allocate a roff renderer for lowdown documents
.Sh LIBRARY
.Lb liblowdown
.Sh SYNOPSIS
.In sys/queue.h
.In stdio.h
.In lowdown.h
.Ft void *
.Fo lowdown_nroff_new
.Fa "const struct lowdown_opts *opts"
.Fc
.Sh DESCRIPTION
Allocates a roff renderer using
.Fa opts->oflags
and
.Fa opts->type ,
or zero and
.Dv LOWDOWN_MS ,
respectively, if
.Fa opts
is
.Dv NULL .
These are documented in
.Xr lowdown 3 .
The returned pointer may be used with multiple invocations of
.Xr lowdown_nroff_rndr 3
and must be freed with
.Xr lowdown_nroff_free 3 .
.Pp
The bits recognised in
.Fa opts->oflags
are
.Dv LOWDOWN_NROFF_GROFF ,
.Dv LOWDOWN_NROFF_NOLINK ,
.Dv LOWDOWN_NROFF_NUMBERED ,
.Dv LOWDOWN_NROFF_SHORTLINK ,
.Dv LOWDOWN_NROFF_SKIP_HTML ,
and
.Dv LOWDOWN_STANDALONE .
.Pp
The values recognised in
.Fa opts->type
are
.Dv LOWDOWN_MAN
and
.Dv LOWDOWN_MS :
anything else triggers
.Dv LOWDOWN_MS .
.Pp
If
.Dv LOWDOWN_NROFF_GROFF
is set in
.Dv LOWDOWN_MAN
mode, macros from the
.Ar man-ext
package as well as the original
.Ar man
are used in output.
These are supported by both groff and mandoc.
If in
.Dv LOWDOWN_MS
mode, GNU extensions to
.Ar ms
are used along with
.Ar mspdf .
These are only supported by groff.
.Sh RETURN VALUES
Returns a pointer to the renderer or
.Dv NULL
on memory failure.
The returned pointer must be freed with
.Xr lowdown_nroff_free 3 .
.Sh EXAMPLES
The following assumes the the string
.Va buf
of length
.Va bsz
consists of Markdown content.
.Bd -literal -offset indent
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_nroff_free(rndr);
lowdown_buf_free(out);
lowdown_node_free(n);
lowdown_doc_free(doc);
.Ed
.Sh SEE ALSO
.Xr lowdown 3 ,
.Xr lowdown_nroff_free 3 ,
.Xr lowdown_nroff_rndr 3 ,
.Pp
This uses both the original troff
.Ar man
macros for
.At v7 ,
defined in
.Xr man 7 ,
and the
.Ar man-ext
groff extensions.
Both are implemented in mandoc.
.Pp
The troff
.Ar ms
macros are defined in
.Xr groff_ms 7 ,
with the
.Ar mspdf
groff extensions described in
.Qq Portable Document Format Publishing with GNU Troff
by Keith Marshall.
Neither are implemented in mandoc.