First step of adding register support. This is inspired by a significant

patch by schwarze@.  This commit adds support to libroff parsing `nr'
into register set defined in regs.h.  This will propogate into libmdoc
and libman in later commits.

8 files changed, 162 insertions, 13 deletions

diff --git a/Makefile b/Makefile
index 134d4a93..9a85b103 100644
--- a/Makefile
+++ b/Makefile
@@ -98,7 +98,7 @@ DATAS	   = arch.in att.in lib.in msec.in st.in \
 
 HEADS	   = mdoc.h libmdoc.h man.h libman.h term.h \
 	     libmandoc.h html.h chars.h out.h main.h roff.h \
-	     mandoc.h
+	     mandoc.h regs.h
 
 GSGMLS	   = mandoc.1.sgml mdoc.3.sgml mdoc.7.sgml \
 	     mandoc_char.7.sgml man.7.sgml man.3.sgml roff.7.sgml \
diff --git a/main.c b/main.c
index 0d63a334..a29c3633 100644
--- a/main.c
+++ b/main.c
@@ -30,10 +30,11 @@
 #include <unistd.h>
 
 #include "mandoc.h"
+#include "regs.h"
+#include "main.h"
 #include "mdoc.h"
 #include "man.h"
 #include "roff.h"
-#include "main.h"
 
 #define	UNCONST(a)	((void *)(uintptr_t)(const void *)(a))
 
@@ -450,11 +451,13 @@ fdesc(struct curparse *curp)
 	struct man	*man;
 	struct mdoc	*mdoc;
 	struct roff	*roff;
+	struct regset	 regs;
 
 	man = NULL;
 	mdoc = NULL;
 	roff = NULL;
 	memset(&ln, 0, sizeof(struct buf));
+	memset(&regs, 0, sizeof(struct regset));
 
 	/*
 	 * Two buffers: ln and buf.  buf is the input file and may be
@@ -537,7 +540,7 @@ fdesc(struct curparse *curp)
 
 		of = 0;
 		do {
-			re = roff_parseln(roff, lnn_start, 
+			re = roff_parseln(roff, &regs, lnn_start, 
 					&ln.buf, &ln.sz, of, &of);
 		} while (ROFF_RERUN == re);
 
diff --git a/mdoc.h b/mdoc.h
index 10767d4f..7fc5b3e4 100644
--- a/mdoc.h
+++ b/mdoc.h
@@ -155,6 +155,7 @@ enum	mdoct {
 
 /* What follows is a list of ALL possible macro arguments. */
 
+/* FIXME: make this into an enum. */
 #define	MDOC_Split	 0
 #define	MDOC_Nosplit	 1
 #define	MDOC_Ragged	 2
diff --git a/regs.h b/regs.h
new file mode 100644
index 00000000..9f176d6d
--- /dev/null
+++ b/regs.h
@@ -0,0 +1,39 @@
+/*	$Id$ */
+/*
+ * Copyright (c) 2010 Kristaps Dzonsons <kristaps@bsd.lv>
+ *
+ * Permission to use, copy, modify, and distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ */
+#ifndef REGS_H
+#define REGS_H
+
+__BEGIN_DECLS
+
+enum	regs {
+	REG_nS = 0,	/* nS */
+	REG__MAX
+};
+
+/*
+ * Registers are passed into libmdoc and libman.  They refer to some
+ * sort of external state.
+ */
+struct	regset {
+	union {
+		int	 i; /* integer value */
+	} regs[REG__MAX];
+};
+
+__END_DECLS
+
+#endif /*!REGS_H*/
diff --git a/roff.3 b/roff.3
index 18b48ad3..30b8aa2b 100644
--- a/roff.3
+++ b/roff.3
@@ -27,6 +27,7 @@
 .Nd roff macro compiler library
 .Sh SYNOPSIS
 .In mandoc.h
+.In regs.h
 .In roff.h
 .Ft "struct roff *"
 .Fn roff_alloc "mandocmsg msgs" "void *data"
diff --git a/roff.7 b/roff.7
index 58fb4d19..e35f37d4 100644
--- a/roff.7
+++ b/roff.7
@@ -268,6 +268,34 @@ This macro is intended to have one argument,
 the name of the request, macro or string to be undefined.
 Currently, it is ignored including its arguments,
 and the number of arguments is not checked.
+.Ss \&nr
+Define a register.
+A register is an arbitrary string value that defines some sort of state,
+which influences parsing and/or formatting.
+Its syntax is as follows:
+.Pp
+.D1 Pf \. Sx \&nr Cm name value
+.Pp
+The
+.Cm value
+may, at the moment, only be an integer.
+The
+.Cm name
+is defined up to the next whitespace.
+The following register
+.Cm name
+requests are recognised:
+.Bl -tag -width Ds
+.It Cm nS
+If set to a positive integer value, certain
+.Xr mdoc 7
+macros will behave as if they are defined in the
+.Em SYNOPSIS
+section to a manual.
+Otherwise, this behaviour is unset (even if called within the
+.Em SYNOPSIS
+section itself).
+.El
 .Ss \&tr
 Output character translation.
 This macro is intended to have one argument,
@@ -287,6 +315,12 @@ file re-write
 .Pp
 .Bl -dash -compact
 .It
+The
+.Cm nS
+request to
+.Sx \&nr
+is only compatible with OpenBSD's groff.
+.It
 Historic groff did not accept white-space buffering the custom END tag
 for the
 .Sx \&ig
diff --git a/roff.c b/roff.c
index f0c23664..2fbff8b7 100644
--- a/roff.c
+++ b/roff.c
@@ -19,12 +19,15 @@
 #endif
 
 #include <assert.h>
+#include <errno.h>
 #include <ctype.h>
+#include <limits.h>
 #include <stdlib.h>
 #include <string.h>
 #include <stdio.h>
 
 #include "mandoc.h"
+#include "regs.h"
 #include "roff.h"
 
 #define	RSTACK_MAX	128
@@ -56,6 +59,7 @@ enum	rofft {
 	ROFF_tr,
 	ROFF_cblock,
 	ROFF_ccond,
+	ROFF_nr,
 	ROFF_MAX
 };
 
@@ -83,6 +87,7 @@ struct	roffnode {
 };
 
 #define	ROFF_ARGS	 struct roff *r, /* parse ctx */ \
+			 struct regset *regs, /* registers */ \
 			 enum rofft tok, /* tok of macro */ \
 		 	 char **bufp, /* input buffer */ \
 			 size_t *szp, /* size of input buffer */ \
@@ -111,8 +116,9 @@ static	enum rofferr	 roff_ccond(ROFF_ARGS);
 static	enum rofferr	 roff_cond(ROFF_ARGS);
 static	enum rofferr	 roff_cond_text(ROFF_ARGS);
 static	enum rofferr	 roff_cond_sub(ROFF_ARGS);
-static	enum roffrule	 roff_evalcond(const char *, int *);
 static	enum rofferr	 roff_line(ROFF_ARGS);
+static	enum rofferr	 roff_nr(ROFF_ARGS);
+static	enum roffrule	 roff_evalcond(const char *, int *);
 
 /* See roff_hash_find() */
 
@@ -138,6 +144,7 @@ static	struct roffmac	 roffs[ROFF_MAX] = {
 	{ "tr", roff_line, NULL, NULL, 0, NULL },
 	{ ".", roff_cblock, NULL, NULL, 0, NULL },
 	{ "\\}", roff_ccond, NULL, NULL, 0, NULL },
+	{ "nr", roff_nr, NULL, NULL, 0, NULL },
 };
 
 static	void		 roff_free1(struct roff *);
@@ -148,6 +155,7 @@ static	int		 roffnode_push(struct roff *,
 				enum rofft, int, int);
 static	void		 roffnode_pop(struct roff *);
 static	enum rofft	 roff_parse(const char *, int *);
+static	int		 roff_parse_nat(const char *, int *);
 
 /* See roff_hash_find() */
 #define	ROFF_HASH(p)	(p[0] - ASCII_LO)
@@ -300,7 +308,7 @@ roff_alloc(const mandocmsg msg, void *data)
 
 
 enum rofferr
-roff_parseln(struct roff *r, int ln, 
+roff_parseln(struct roff *r, struct regset *regs, int ln, 
 		char **bufp, size_t *szp, int pos, int *offs)
 {
 	enum rofft	 t;
@@ -318,7 +326,8 @@ roff_parseln(struct roff *r, int ln,
 		ROFF_DEBUG("roff: intercept scoped text: %s, [%s]\n", 
 				roffs[t].name, &(*bufp)[pos]);
 		return((*roffs[t].text)
-				(r, t, bufp, szp, ln, pos, pos, offs));
+				(r, regs, t, bufp, 
+				 szp, ln, pos, pos, offs));
 	} else if ( ! ROFF_CTL((*bufp)[pos])) {
 		ROFF_DEBUG("roff: pass non-scoped text: [%s]\n", 
 				&(*bufp)[pos]);
@@ -336,7 +345,8 @@ roff_parseln(struct roff *r, int ln,
 		ROFF_DEBUG("roff: intercept scoped context: %s\n", 
 				roffs[t].name);
 		return((*roffs[t].sub)
-				(r, t, bufp, szp, ln, pos, pos, offs));
+				(r, regs, t, bufp, 
+				 szp, ln, pos, pos, offs));
 	}
 
 	/*
@@ -356,7 +366,8 @@ roff_parseln(struct roff *r, int ln,
 			roffs[t].name, &(*bufp)[pos]);
 	assert(roffs[t].proc);
 	return((*roffs[t].proc)
-			(r, t, bufp, szp, ln, ppos, pos, offs));
+			(r, regs, t, bufp, 
+			 szp, ln, ppos, pos, offs));
 }
 
 
@@ -412,6 +423,26 @@ roff_parse(const char *buf, int *pos)
 }
 
 
+static int
+roff_parse_nat(const char *buf, int *res)
+{
+	char		*ep;
+	long		 lval;
+
+	errno = 0;
+	lval = strtol(buf, &ep, 10);
+	if (buf[0] == '\0' || *ep != '\0')
+		return(0);
+	if ((errno == ERANGE && 
+			(lval == LONG_MAX || lval == LONG_MIN)) ||
+			(lval > INT_MAX || lval <= 0))
+		return(0);
+
+	*res = (int)lval;
+	return(1);
+}
+
+
 /* ARGSUSED */
 static enum rofferr
 roff_cblock(ROFF_ARGS)
@@ -622,7 +653,7 @@ roff_block_sub(ROFF_ARGS)
 		return(ROFF_IGN);
 
 	assert(roffs[t].proc);
-	return((*roffs[t].proc)(r, t, bufp, 
+	return((*roffs[t].proc)(r, regs, t, bufp, 
 			szp, ln, ppos, pos, offs));
 }
 
@@ -673,7 +704,7 @@ roff_cond_sub(ROFF_ARGS)
 
 	assert(roffs[t].proc);
 	return((*roffs[t].proc)
-			(r, t, bufp, szp, ln, ppos, pos, offs));
+			(r, regs, t, bufp, szp, ln, ppos, pos, offs));
 }
 
 
@@ -732,6 +763,15 @@ roff_evalcond(const char *v, int *pos)
 
 /* ARGSUSED */
 static enum rofferr
+roff_line(ROFF_ARGS)
+{
+
+	return(ROFF_IGN);
+}
+
+
+/* ARGSUSED */
+static enum rofferr
 roff_cond(ROFF_ARGS)
 {
 	int		 sv;
@@ -838,8 +878,39 @@ roff_cond(ROFF_ARGS)
 
 /* ARGSUSED */
 static enum rofferr
-roff_line(ROFF_ARGS)
+roff_nr(ROFF_ARGS)
 {
+	const char	*key, *val;
+
+	key = &(*bufp)[pos];
+
+	/* Parse register request. */
+	while ((*bufp)[pos] && ' ' != (*bufp)[pos])
+		pos++;
+
+	/*
+	 * Set our nil terminator.  Because this line is going to be
+	 * ignored anyway, we can munge it as we please.
+	 */
+	if ((*bufp)[pos])
+		(*bufp)[pos++] = '\0';
+
+	/* Skip whitespace to register token. */
+	while ((*bufp)[pos] && ' ' == (*bufp)[pos])
+		pos++;
+
+	val = &(*bufp)[pos];
+
+	/* Process register token. */
+
+	if (0 == strcmp(key, "nS")) {
+		if ( ! roff_parse_nat(val, &regs->regs[(int)REG_nS].i))
+			regs->regs[(int)REG_nS].i = 0;
+
+		ROFF_DEBUG("roff: register nS: %d\n", 
+				regs->regs[(int)REG_nS].i);
+	} else
+		ROFF_DEBUG("roff: ignoring register: %s\n", key);
 
 	return(ROFF_IGN);
 }
diff --git a/roff.h b/roff.h
index bc2b50c1..9185f912 100644
--- a/roff.h
+++ b/roff.h
@@ -31,8 +31,8 @@ struct	roff;
 void	 	  roff_free(struct roff *);
 struct	roff	 *roff_alloc(mandocmsg, void *);
 void		  roff_reset(struct roff *);
-enum	rofferr	  roff_parseln(struct roff *, int, 
-			char **, size_t *, int, int *);
+enum	rofferr	  roff_parseln(struct roff *, struct regset *,
+			int, char **, size_t *, int, int *);
 int		  roff_endparse(struct roff *);
 
 __END_DECLS