Sync to OpenBSD:

[mandoc.git] / man.c

diff --git a/man.c b/man.c
index c00fd6eb6466a17eb0f0fba9742094828335d7e1..147662e91253b465dab70f77f1479219e30bf7ae 100644 (file)
--- a/man.c
+++ b/man.c
@@ -1,46 +1,58 @@
-/* $Id: man.c,v 1.4 2009/03/25 15:17:49 kristaps Exp $ */
+/*     $Id: man.c,v 1.92 2010/12/08 10:58:22 kristaps Exp $ */

 /*
 /*

- * Copyright (c) 2008, 2009 Kristaps Dzonsons <kristaps@openbsd.org>
+ * Copyright (c) 2008, 2009, 2010 Kristaps Dzonsons <kristaps@bsd.lv>

  *
  * Permission to use, copy, modify, and distribute this software for any
  *
  * 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.
+ * 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.
+ * 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.

  */
  */

+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#include <sys/types.h>
+

 #include <assert.h>
 #include <assert.h>

-#include <ctype.h>
-#include <err.h>

 #include <stdarg.h>
 #include <stdlib.h>
 #include <stdio.h>
 #include <string.h>
 
 #include <stdarg.h>
 #include <stdlib.h>
 #include <stdio.h>
 #include <string.h>
 

+#include "mandoc.h"

 #include "libman.h"
 #include "libman.h"

+#include "libmandoc.h"

 
 const  char *const __man_macronames[MAN_MAX] = {                
 
 const  char *const __man_macronames[MAN_MAX] = {                

-       "\\\"",         "TH",           "SH",           "SS",
+       "br",           "TH",           "SH",           "SS",

        "TP",           "LP",           "PP",           "P",
        "IP",           "HP",           "SM",           "SB",
        "BI",           "IB",           "BR",           "RB",
        "TP",           "LP",           "PP",           "P",
        "IP",           "HP",           "SM",           "SB",
        "BI",           "IB",           "BR",           "RB",

-       "R",            "B",            "I",            "IR"
+       "R",            "B",            "I",            "IR",
+       "RI",           "na",           "sp",           "nf",
+       "fi",           "RE",           "RS",           "DT",
+       "UC",           "PD",           "AT",           "in",
+       "ft"

        };
 
 const  char * const *man_macronames = __man_macronames;
 
        };
 
 const  char * const *man_macronames = __man_macronames;
 

-static struct man_node *man_node_alloc(int, int, enum man_type);
+static struct man_node *man_node_alloc(int, int, 
+                               enum man_type, enum mant);

 static int              man_node_append(struct man *, 
                                struct man_node *);
 static int              man_node_append(struct man *, 
                                struct man_node *);

-static int              man_ptext(struct man *, int, char *);
-static int              man_pmacro(struct man *, int, char *);
+static void             man_node_free(struct man_node *);
+static void             man_node_unlink(struct man *, 
+                               struct man_node *);
+static int              man_ptext(struct man *, int, char *, int);
+static int              man_pmacro(struct man *, int, char *, int);

 static void             man_free1(struct man *);
 static void             man_alloc1(struct man *);
 
 static void             man_free1(struct man *);
 static void             man_alloc1(struct man *);
 


@@ -75,29 +87,23 @@ man_free(struct man *man)
 {
 
        man_free1(man);
 {
 
        man_free1(man);

-
-       if (man->htab)
-               man_hash_free(man->htab);

        free(man);
 }
 
 
 struct man *
        free(man);
 }
 
 
 struct man *

-man_alloc(void *data, const struct man_cb *cb)
+man_alloc(struct regset *regs, void *data, mandocmsg msg)

 {
        struct man      *p;
 
 {
        struct man      *p;
 

-       p = calloc(1, sizeof(struct man));
-       if (NULL == p)
-               err(1, "calloc");
+       p = mandoc_calloc(1, sizeof(struct man));

 
 

-       man_alloc1(p);
-
-       if (cb)
-               (void)memcpy(&p->cb, cb, sizeof(struct man_cb));
-
-       p->htab = man_hash_alloc();
+       man_hash_init();

        p->data = data;
        p->data = data;

+       p->msg = msg;
+       p->regs = regs;
+
+       man_alloc1(p);

        return(p);
 }
 
        return(p);
 }
 


@@ -116,12 +122,15 @@ man_endparse(struct man *m)
 
 
 int
 
 
 int

-man_parseln(struct man *m, int ln, char *buf)
+man_parseln(struct man *m, int ln, char *buf, int offs)

 {
 
 {
 

-       return('.' == *buf ? 
-                       man_pmacro(m, ln, buf) : 
-                       man_ptext(m, ln, buf));
+       if (MAN_HALT & m->flags)
+               return(0);
+
+       return(('.' == buf[offs] || '\'' == buf[offs]) ? 
+                       man_pmacro(m, ln, buf, offs) : 
+                       man_ptext(m, ln, buf, offs));

 }
 
 
 }
 
 


@@ -130,13 +139,17 @@ man_free1(struct man *man)
 {
 
        if (man->first)
 {
 
        if (man->first)

-               man_node_freelist(man->first);
+               man_node_delete(man, man->first);

        if (man->meta.title)
                free(man->meta.title);
        if (man->meta.title)
                free(man->meta.title);

-       if (man->meta.os)
-               free(man->meta.os);
+       if (man->meta.source)
+               free(man->meta.source);
+       if (man->meta.rawdate)
+               free(man->meta.rawdate);

        if (man->meta.vol)
                free(man->meta.vol);
        if (man->meta.vol)
                free(man->meta.vol);

+       if (man->meta.msec)
+               free(man->meta.msec);

 }
 
 
 }
 
 


@@ -144,13 +157,12 @@ static void
 man_alloc1(struct man *m)
 {
 
 man_alloc1(struct man *m)
 {
 

-       bzero(&m->meta, sizeof(struct man_meta));
+       memset(&m->meta, 0, sizeof(struct man_meta));

        m->flags = 0;
        m->flags = 0;

-       m->last = calloc(1, sizeof(struct man_node));
-       if (NULL == m->last)
-               err(1, "calloc");
+       m->last = mandoc_calloc(1, sizeof(struct man_node));

        m->first = m->last;
        m->last->type = MAN_ROOT;
        m->first = m->last;
        m->last->type = MAN_ROOT;

+       m->last->tok = MAN_MAX;

        m->next = MAN_NEXT_CHILD;
 }
 
        m->next = MAN_NEXT_CHILD;
 }
 


@@ -177,11 +189,25 @@ man_node_append(struct man *man, struct man_node *p)
                abort();
                /* NOTREACHED */
        }
                abort();
                /* NOTREACHED */
        }

+       
+       assert(p->parent);
+       p->parent->nchild++;

 
 

-#if 0
-       if ( ! man_action_pre(man, p))
+       if ( ! man_valid_pre(man, p))

                return(0);
                return(0);

-#endif
+
+       switch (p->type) {
+       case (MAN_HEAD):
+               assert(MAN_BLOCK == p->parent->type);
+               p->parent->head = p;
+               break;
+       case (MAN_BODY):
+               assert(MAN_BLOCK == p->parent->type);
+               p->parent->body = p;
+               break;
+       default:
+               break;
+       }

 
        man->last = p;
 
 
        man->last = p;
 


@@ -189,10 +215,6 @@ man_node_append(struct man *man, struct man_node *p)
        case (MAN_TEXT):
                if ( ! man_valid_post(man))
                        return(0);
        case (MAN_TEXT):
                if ( ! man_valid_post(man))
                        return(0);

-#if 0
-               if ( ! man_action_post(man))
-                       return(0);
-#endif

                break;
        default:
                break;
                break;
        default:
                break;


@@ -203,47 +225,99 @@ man_node_append(struct man *man, struct man_node *p)
 
 
 static struct man_node *
 
 
 static struct man_node *

-man_node_alloc(int line, int pos, enum man_type type)
+man_node_alloc(int line, int pos, enum man_type type, enum mant tok)

 {
        struct man_node *p;
 
 {
        struct man_node *p;
 

-       if (NULL == (p = calloc(1, sizeof(struct man_node))))
-               err(1, "malloc");
+       p = mandoc_calloc(1, sizeof(struct man_node));

        p->line = line;
        p->pos = pos;
        p->type = type;
        p->line = line;
        p->pos = pos;
        p->type = type;

-
+       p->tok = tok;

        return(p);
 }
 
 
 int
        return(p);
 }
 
 
 int

-man_elem_alloc(struct man *man, int line, int pos, int tok)
+man_elem_alloc(struct man *m, int line, int pos, enum mant tok)

 {
        struct man_node *p;
 
 {
        struct man_node *p;
 

-       p = man_node_alloc(line, pos, MAN_ELEM);
-       p->tok = tok;
+       p = man_node_alloc(line, pos, MAN_ELEM, tok);
+       if ( ! man_node_append(m, p))
+               return(0);
+       m->next = MAN_NEXT_CHILD;
+       return(1);
+}
+

 
 

-       return(man_node_append(man, p));
+int
+man_head_alloc(struct man *m, int line, int pos, enum mant tok)
+{
+       struct man_node *p;
+
+       p = man_node_alloc(line, pos, MAN_HEAD, tok);
+       if ( ! man_node_append(m, p))
+               return(0);
+       m->next = MAN_NEXT_CHILD;
+       return(1);

 }
 
 
 int
 }
 
 
 int

-man_word_alloc(struct man *man, 
-               int line, int pos, const char *word)
+man_body_alloc(struct man *m, int line, int pos, enum mant tok)

 {
 {

-       struct man_node *p;
+       struct man_node *p;
+
+       p = man_node_alloc(line, pos, MAN_BODY, tok);
+       if ( ! man_node_append(m, p))
+               return(0);
+       m->next = MAN_NEXT_CHILD;
+       return(1);
+}

 
 

-       p = man_node_alloc(line, pos, MAN_TEXT);
-       if (NULL == (p->string = strdup(word)))
-               err(1, "strdup");

 
 

-       return(man_node_append(man, p));
+int
+man_block_alloc(struct man *m, int line, int pos, enum mant tok)
+{
+       struct man_node *p;
+
+       p = man_node_alloc(line, pos, MAN_BLOCK, tok);
+       if ( ! man_node_append(m, p))
+               return(0);
+       m->next = MAN_NEXT_CHILD;
+       return(1);

 }
 
 
 }
 
 

-void
+int
+man_word_alloc(struct man *m, int line, int pos, const char *word)
+{
+       struct man_node *n;
+       size_t           sv, len;
+
+       len = strlen(word);
+
+       n = man_node_alloc(line, pos, MAN_TEXT, MAN_MAX);
+       n->string = mandoc_malloc(len + 1);
+       sv = strlcpy(n->string, word, len + 1);
+
+       /* Prohibit truncation. */
+       assert(sv < len + 1);
+
+       if ( ! man_node_append(m, n))
+               return(0);
+
+       m->next = MAN_NEXT_SIBLING;
+       return(1);
+}
+
+
+/*
+ * Free all of the resources held by a node.  This does NOT unlink a
+ * node from its context; for that, see man_node_unlink().
+ */
+static void

 man_node_free(struct man_node *p)
 {
 
 man_node_free(struct man_node *p)
 {
 


@@ -254,73 +328,153 @@ man_node_free(struct man_node *p)
 
 
 void
 
 
 void

-man_node_freelist(struct man_node *p)
+man_node_delete(struct man *m, struct man_node *p)

 {
 
 {
 

-       if (p->child)
-               man_node_freelist(p->child);
-       if (p->next)
-               man_node_freelist(p->next);
+       while (p->child)
+               man_node_delete(m, p->child);

 
 

+       man_node_unlink(m, p);

        man_node_free(p);
 }
 
 
 static int
        man_node_free(p);
 }
 
 
 static int

-man_ptext(struct man *m, int line, char *buf)
+man_ptext(struct man *m, int line, char *buf, int offs)

 {
 {

+       int              i;
+
+       /* Ignore bogus comments. */
+
+       if ('\\' == buf[offs] && 
+                       '.' == buf[offs + 1] && 
+                       '"' == buf[offs + 2])
+               return(man_pmsg(m, line, offs, MANDOCERR_BADCOMMENT));
+
+       /* Literal free-form text whitespace is preserved. */
+
+       if (MAN_LITERAL & m->flags) {
+               if ( ! man_word_alloc(m, line, offs, buf + offs))
+                       return(0);
+               goto descope;
+       }

 
 

-       if ( ! man_word_alloc(m, line, 0, buf))
+       /* Pump blank lines directly into the backend. */
+
+       for (i = offs; ' ' == buf[i]; i++)
+               /* Skip leading whitespace. */ ;
+
+       if ('\0' == buf[i]) {
+               /* Allocate a blank entry. */
+               if ( ! man_word_alloc(m, line, offs, ""))
+                       return(0);
+               goto descope;
+       }
+
+       /* 
+        * Warn if the last un-escaped character is whitespace. Then
+        * strip away the remaining spaces (tabs stay!).   
+        */
+
+       i = (int)strlen(buf);
+       assert(i);
+
+       if (' ' == buf[i - 1] || '\t' == buf[i - 1]) {
+               if (i > 1 && '\\' != buf[i - 2])
+                       if ( ! man_pmsg(m, line, i - 1, MANDOCERR_EOLNSPACE))
+                               return(0);
+
+               for (--i; i && ' ' == buf[i]; i--)
+                       /* Spin back to non-space. */ ;
+
+               /* Jump ahead of escaped whitespace. */
+               i += '\\' == buf[i] ? 2 : 1;
+
+               buf[i] = '\0';
+       }
+
+       if ( ! man_word_alloc(m, line, offs, buf + offs))

                return(0);
                return(0);

-       m->next = MAN_NEXT_SIBLING;
-       return(1);
+
+       /*
+        * End-of-sentence check.  If the last character is an unescaped
+        * EOS character, then flag the node as being the end of a
+        * sentence.  The front-end will know how to interpret this.
+        */
+
+       assert(i);
+       if (mandoc_eos(buf, (size_t)i, 0))
+               m->last->flags |= MAN_EOS;
+
+descope:
+       /*
+        * Co-ordinate what happens with having a next-line scope open:
+        * first close out the element scope (if applicable), then close
+        * out the block scope (also if applicable).
+        */
+
+       if (MAN_ELINE & m->flags) {
+               m->flags &= ~MAN_ELINE;
+               if ( ! man_unscope(m, m->last->parent, MANDOCERR_MAX))
+                       return(0);
+       }
+
+       if ( ! (MAN_BLINE & m->flags))
+               return(1);
+       m->flags &= ~MAN_BLINE;
+
+       if ( ! man_unscope(m, m->last->parent, MANDOCERR_MAX))
+               return(0);
+       return(man_body_alloc(m, line, offs, m->last->tok));

 }
 
 
 int
 }
 
 
 int

-man_pmacro(struct man *m, int ln, char *buf)
+man_pmacro(struct man *m, int ln, char *buf, int offs)

 {
 {

-       int               i, c;
-       char              mac[5];
+       int              i, j, ppos;
+       enum mant        tok;
+       char             mac[5];
+       struct man_node *n;

 
        /* Comments and empties are quickly ignored. */
 
 
        /* Comments and empties are quickly ignored. */
 

-       if (0 == buf[1])
+       offs++;
+
+       if ('\0' == buf[offs])

                return(1);
 
                return(1);
 

-       if (' ' == buf[1]) {
-               i = 2;
-               while (buf[i] && ' ' == buf[i])
+       i = offs;
+
+       /*
+        * Skip whitespace between the control character and initial
+        * text.  "Whitespace" is both spaces and tabs.
+        */
+
+       if (' ' == buf[i] || '\t' == buf[i]) {
+               i++;
+               while (buf[i] && (' ' == buf[i] || '\t' == buf[i]))

                        i++;
                        i++;

-               if (0 == buf[i])
-                       return(1);
-               warnx("invalid syntax");
-               return(0);
+               if ('\0' == buf[i])
+                       goto out;

        }
 
        }
 

-       if (buf[1] && '\\' == buf[1])
-               if (buf[2] && '\"' == buf[2])
-                       return(1);
+       ppos = i;

 
 

-       /* Copy the first word into a nil-terminated buffer. */
+       /*
+        * Copy the first word into a nil-terminated buffer.
+        * Stop copying when a tab, space, or eoln is encountered.
+        */

 
 

-       for (i = 1; i < 5; i++) {
-               if (0 == (mac[i - 1] = buf[i]))
-                       break;
-               else if (' ' == buf[i])
-                       break;
-       }
+       j = 0;
+       while (j < 4 && '\0' != buf[i] && ' ' != buf[i] && '\t' != buf[i])
+               mac[j++] = buf[i++];
+       mac[j] = '\0';

 
 

-       mac[i - 1] = 0;
-
-       if (i == 5 || i <= 1) {
-               warnx("unknown macro: %s", mac);
-               goto err;
-       } 
-       
-       if (MAN_MAX == (c = man_hash_find(m->htab, mac))) {
-               warnx("unknown macro: %s", mac);
-               goto err;
+       tok = (j > 0 && j < 4) ? man_hash_find(mac) : MAN_MAX;
+       if (MAN_MAX == tok) {
+               man_vmsg(m, MANDOCERR_MACRO, ln, ppos, "%s", buf + ppos - 1);
+               return(1);

        }
 
        /* The macro is sane.  Jump to the next word. */
        }
 
        /* The macro is sane.  Jump to the next word. */


@@ -328,12 +482,91 @@ man_pmacro(struct man *m, int ln, char *buf)
        while (buf[i] && ' ' == buf[i])
                i++;
 
        while (buf[i] && ' ' == buf[i])
                i++;
 

-       /* Begin recursive parse sequence. */
+       /* 
+        * Trailing whitespace.  Note that tabs are allowed to be passed
+        * into the parser as "text", so we only warn about spaces here.
+        */
+
+       if ('\0' == buf[i] && ' ' == buf[i - 1])
+               if ( ! man_pmsg(m, ln, i - 1, MANDOCERR_EOLNSPACE))
+                       goto err;
+
+       /* 
+        * Remove prior ELINE macro, as it's being clobbered by a new
+        * macro.  Note that NSCOPED macros do not close out ELINE
+        * macros---they don't print text---so we let those slip by.
+        */
+
+       if ( ! (MAN_NSCOPED & man_macros[tok].flags) &&
+                       m->flags & MAN_ELINE) {
+               n = m->last;
+               assert(MAN_TEXT != n->type);
+
+               /* Remove repeated NSCOPED macros causing ELINE. */
+
+               if (MAN_NSCOPED & man_macros[n->tok].flags)
+                       n = n->parent;
+
+               man_vmsg(m, MANDOCERR_LINESCOPE, n->line, n->pos,
+                               "%s", man_macronames[n->tok]);

 
 

-       if ( ! man_macro(m, c, ln, 1, &i, buf))
+               man_node_delete(m, n);
+               m->flags &= ~MAN_ELINE;
+       }
+
+       /*
+        * Save the fact that we're in the next-line for a block.  In
+        * this way, embedded roff instructions can "remember" state
+        * when they exit.
+        */
+
+       if (MAN_BLINE & m->flags)
+               m->flags |= MAN_BPLINE;
+
+       /* Call to handler... */
+
+       assert(man_macros[tok].fp);
+       if ( ! (*man_macros[tok].fp)(m, tok, ln, ppos, &i, buf))

                goto err;
 
                goto err;
 

-       return(1);
+out:
+       /* 
+        * We weren't in a block-line scope when entering the
+        * above-parsed macro, so return.
+        */
+
+       if ( ! (MAN_BPLINE & m->flags)) {
+               m->flags &= ~MAN_ILINE; 
+               return(1);
+       }
+       m->flags &= ~MAN_BPLINE;
+
+       /*
+        * If we're in a block scope, then allow this macro to slip by
+        * without closing scope around it.
+        */
+
+       if (MAN_ILINE & m->flags) {
+               m->flags &= ~MAN_ILINE;
+               return(1);
+       }
+
+       /* 
+        * If we've opened a new next-line element scope, then return
+        * now, as the next line will close out the block scope.
+        */
+
+       if (MAN_ELINE & m->flags)
+               return(1);
+
+       /* Close out the block scope opened in the prior line.  */
+
+       assert(MAN_BLINE & m->flags);
+       m->flags &= ~MAN_BLINE;
+
+       if ( ! man_unscope(m, m->last->parent, MANDOCERR_MAX))
+               return(0);
+       return(man_body_alloc(m, ln, offs, m->last->tok));

 
 err:   /* Error out. */
 
 
 err:   /* Error out. */
 


@@ -343,34 +576,56 @@ err:      /* Error out. */
 
 
 int
 
 
 int

-man_verr(struct man *man, int ln, int pos, const char *fmt, ...)
+man_vmsg(struct man *man, enum mandocerr t, 
+               int ln, int pos, const char *fmt, ...)

 {
        char             buf[256];
        va_list          ap;
 
 {
        char             buf[256];
        va_list          ap;
 

-       if (NULL == man->cb.man_err)
-               return(0);
-

        va_start(ap, fmt);
        va_start(ap, fmt);

-       (void)vsnprintf(buf, sizeof(buf) - 1, fmt, ap);
+       vsnprintf(buf, sizeof(buf) - 1, fmt, ap);

        va_end(ap);
        va_end(ap);

-       return((*man->cb.man_err)(man->data, ln, pos, buf));
+       return((*man->msg)(t, man->data, ln, pos, buf));

 }
 
 
 }
 
 

-int
-man_vwarn(struct man *man, int ln, int pos, const char *fmt, ...)
+/*
+ * Unlink a node from its context.  If "m" is provided, the last parse
+ * point will also be adjusted accordingly.
+ */
+static void
+man_node_unlink(struct man *m, struct man_node *n)

 {
 {

-       char             buf[256];
-       va_list          ap;

 
 

-       if (NULL == man->cb.man_warn)
-               return(0);
+       /* Adjust siblings. */

 
 

-       va_start(ap, fmt);
-       (void)vsnprintf(buf, sizeof(buf) - 1, fmt, ap);
-       va_end(ap);
-       return((*man->cb.man_warn)(man->data, ln, pos, buf));
-}
+       if (n->prev)
+               n->prev->next = n->next;
+       if (n->next)
+               n->next->prev = n->prev;

 
 

+       /* Adjust parent. */

 
 

+       if (n->parent) {
+               n->parent->nchild--;
+               if (n->parent->child == n)
+                       n->parent->child = n->prev ? n->prev : n->next;
+       }
+
+       /* Adjust parse point, if applicable. */
+
+       if (m && m->last == n) {
+               /*XXX: this can occur when bailing from validation. */
+               /*assert(NULL == n->next);*/
+               if (n->prev) {
+                       m->last = n->prev;
+                       m->next = MAN_NEXT_SIBLING;
+               } else {
+                       m->last = n->parent;
+                       m->next = MAN_NEXT_CHILD;
+               }
+       }
+
+       if (m && m->first == n)
+               m->first = NULL;
+}