]> git.cameronkatri.com Git - mandoc.git/blobdiff - validate.c
Printing invalid escape sequences.
[mandoc.git] / validate.c
index 796153947ef11745a1e960b88f8102562406e9f3..2ebd427d198b7e980c9be6b126bf058f0b0a51df 100644 (file)
@@ -1,4 +1,4 @@
-/* $Id: validate.c,v 1.3 2008/11/30 12:41:45 kristaps Exp $ */
+/* $Id: validate.c,v 1.72 2009/03/08 11:48:44 kristaps Exp $ */
 /*
  * Copyright (c) 2008 Kristaps Dzonsons <kristaps@kth.se>
  *
  * TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
  * PERFORMANCE OF THIS SOFTWARE.
  */
-#include <sys/param.h>
-
 #include <assert.h>
 #include <ctype.h>
-#include <err.h>
-#include <stdio.h>
+#include <stdarg.h>
 #include <stdlib.h>
-#include <string.h>
 
-#include "libmdocml.h"
 #include "private.h"
 
-#define        INDENT           4
-
-#ifdef __linux__ /* FIXME */
-#define        strlcat          strncat
-#endif
+/* FIXME: .Bl -diag can't have non-text children in HEAD. */
+/* TODO: ignoring Pp (it's superfluous in some invocations). */
 
-struct md_valid {
-       const struct md_args    *args;
-       const struct md_rbuf    *rbuf;
-       struct md_mbuf  *mbuf;
-       struct rofftree *tree;
+/*
+ * Pre- and post-validate macros as they're parsed.  Pre-validation
+ * occurs when the macro has been detected and its arguments parsed.
+ * Post-validation occurs when all child macros have also been parsed.
+ * In the ELEMENT case, this is simply the parameters of the macro; in
+ * the BLOCK case, this is the HEAD, BODY, TAIL and so on.
+ */
 
-       size_t           indent;
-       size_t           pos;
+#define        PRE_ARGS        struct mdoc *mdoc, const struct mdoc_node *n
+#define        POST_ARGS       struct mdoc *mdoc
+
+enum   merr {
+       ENODATA,
+       ENOPROLOGUE,
+       ELINE,
+       EATT,
+       ENAME,
+       ELISTTYPE,
+       EDISPTYPE,
+       EMULTIDISP,
+       EMULTILIST,
+       EARGREP,
+       EBOOL,
+       ENESTDISP
+};
 
-       int              flags;
-#define        MD_LITERAL      (1 << 0)
+enum   mwarn {
+       WWRONGMSEC,
+       WSECOOO,
+       WSECREP,
+       WBADSTAND,
+       WNAMESECINC,
+       WNOMULTILINE,
+       WMULTILINE,
+       WLINE,
+       WNOLINE,
+       WPROLOOO,
+       WPROLREP,
+       WARGVAL,
+       WBADSEC,
+       WBADMSEC
 };
 
-static void             roffmsg(void *arg, enum roffmsg, 
-                               const char *, const char *, char *);
-static int              roffhead(void *);
-static int              rofftail(void *);
-static int              roffin(void *, int, int *, char **);
-static int              roffdata(void *, char *);
-static int              roffout(void *, int);
-static int              roffblkin(void *, int, int *, char **);
-static int              roffblkout(void *, int);
-static int              roffspecial(void *, int);
+typedef        int     (*v_pre)(PRE_ARGS);
+typedef        int     (*v_post)(POST_ARGS);
 
-static int              mbuf_newline(struct md_valid *);
-static int              mbuf_indent(struct md_valid *);
-static int              mbuf_data(struct md_valid *, char *);
+struct valids {
+       v_pre   *pre;
+       v_post  *post;
+};
 
+/* Utility checks. */
+
+static int     nwarn(struct mdoc *, 
+                       const struct mdoc_node *, enum mwarn);
+static int     nerr(struct mdoc *, 
+                       const struct mdoc_node *, enum merr);
+static int     check_parent(PRE_ARGS, int, enum mdoc_type);
+static int     check_msec(PRE_ARGS, ...);
+static int     check_sec(PRE_ARGS, ...);
+static int     check_stdarg(PRE_ARGS);
+static int     check_text(struct mdoc *, 
+                       int, int, const char *);
+static int     check_argv(struct mdoc *, 
+                       const struct mdoc_node *,
+                       const struct mdoc_argv *);
+static int     check_args(struct mdoc *, 
+                       const struct mdoc_node *);
+static int     err_child_lt(struct mdoc *, const char *, int);
+static int     warn_child_lt(struct mdoc *, const char *, int);
+static int     err_child_gt(struct mdoc *, const char *, int);
+static int     warn_child_gt(struct mdoc *, const char *, int);
+static int     err_child_eq(struct mdoc *, const char *, int);
+static int     warn_child_eq(struct mdoc *, const char *, int);
+static inline int count_child(struct mdoc *);
+static inline int warn_count(struct mdoc *, const char *, 
+                       int, const char *, int);
+static inline int err_count(struct mdoc *, const char *, 
+                       int, const char *, int);
+static int     pre_an(PRE_ARGS);
+static int     pre_bd(PRE_ARGS);
+static int     pre_bl(PRE_ARGS);
+static int     pre_cd(PRE_ARGS);
+static int     pre_dd(PRE_ARGS);
+static int     pre_display(PRE_ARGS);
+static int     pre_dt(PRE_ARGS);
+static int     pre_er(PRE_ARGS);
+static int     pre_ex(PRE_ARGS);
+static int     pre_fd(PRE_ARGS);
+static int     pre_it(PRE_ARGS);
+static int     pre_lb(PRE_ARGS);
+static int     pre_os(PRE_ARGS);
+static int     pre_prologue(PRE_ARGS);
+static int     pre_rv(PRE_ARGS);
+static int     pre_sh(PRE_ARGS);
+static int     pre_ss(PRE_ARGS);
+static int     herr_ge1(POST_ARGS);
+static int     hwarn_le1(POST_ARGS);
+static int     herr_eq0(POST_ARGS);
+static int     eerr_eq0(POST_ARGS);
+static int     eerr_le2(POST_ARGS);
+static int     eerr_eq1(POST_ARGS);
+static int     eerr_ge1(POST_ARGS);
+static int     ewarn_eq0(POST_ARGS);
+static int     ewarn_eq1(POST_ARGS);
+static int     bwarn_ge1(POST_ARGS);
+static int     hwarn_eq1(POST_ARGS);
+static int     ewarn_ge1(POST_ARGS);
+static int     ebool(POST_ARGS);
+static int     post_an(POST_ARGS);
+static int     post_at(POST_ARGS);
+static int     post_bf(POST_ARGS);
+static int     post_bl(POST_ARGS);
+static int     post_ex(POST_ARGS);
+static int     post_it(POST_ARGS);
+static int     post_nm(POST_ARGS);
+static int     post_root(POST_ARGS);
+static int     post_sh(POST_ARGS);
+static int     post_sh_body(POST_ARGS);
+static int     post_sh_head(POST_ARGS);
+static int     post_st(POST_ARGS);
+
+static v_pre   pres_an[] = { pre_an, NULL };
+static v_pre   pres_bd[] = { pre_display, pre_bd, NULL };
+static v_pre   pres_bl[] = { pre_bl, NULL };
+static v_pre   pres_cd[] = { pre_cd, NULL };
+static v_pre   pres_dd[] = { pre_prologue, pre_dd, NULL };
+static v_pre   pres_d1[] = { pre_display, NULL };
+static v_pre   pres_dt[] = { pre_prologue, pre_dt, NULL };
+static v_pre   pres_er[] = { pre_er, NULL };
+static v_pre   pres_ex[] = { pre_ex, NULL };
+static v_pre   pres_fd[] = { pre_fd, NULL };
+static v_pre   pres_it[] = { pre_it, NULL };
+static v_pre   pres_lb[] = { pre_lb, NULL };
+static v_pre   pres_os[] = { pre_prologue, pre_os, NULL };
+static v_pre   pres_rv[] = { pre_rv, NULL };
+static v_pre   pres_sh[] = { pre_sh, NULL };
+static v_pre   pres_ss[] = { pre_ss, NULL };
+static v_post  posts_bool[] = { eerr_eq1, ebool, NULL };
+static v_post  posts_bd[] = { herr_eq0, bwarn_ge1, NULL };
+static v_post  posts_text[] = { eerr_ge1, NULL };
+static v_post  posts_wtext[] = { ewarn_ge1, NULL };
+static v_post  posts_notext[] = { eerr_eq0, NULL };
+static v_post  posts_wline[] = { bwarn_ge1, herr_eq0, NULL };
+static v_post  posts_sh[] = { herr_ge1, bwarn_ge1, post_sh, NULL };
+static v_post  posts_bl[] = { herr_eq0, bwarn_ge1, post_bl, NULL };
+static v_post  posts_it[] = { post_it, NULL };
+static v_post  posts_in[] = { ewarn_eq1, NULL };
+static v_post  posts_ss[] = { herr_ge1, NULL };
+static v_post  posts_pf[] = { eerr_eq1, NULL };
+static v_post  posts_lb[] = { eerr_eq1, NULL };
+static v_post  posts_st[] = { eerr_eq1, post_st, NULL };
+static v_post  posts_pp[] = { ewarn_eq0, NULL };
+static v_post  posts_ex[] = { eerr_eq0, post_ex, NULL };
+static v_post  posts_an[] = { post_an, NULL };
+static v_post  posts_at[] = { post_at, NULL };
+static v_post  posts_xr[] = { eerr_ge1, eerr_le2, NULL };
+static v_post  posts_nm[] = { post_nm, NULL };
+static v_post  posts_bf[] = { hwarn_le1, post_bf, NULL };
+static v_post  posts_rs[] = { herr_eq0, bwarn_ge1, NULL };
+static v_post  posts_fo[] = { hwarn_eq1, bwarn_ge1, NULL };
+static v_post  posts_bk[] = { herr_eq0, bwarn_ge1, NULL };
+static v_post  posts_fd[] = { ewarn_ge1, NULL };
+
+const  struct valids mdoc_valids[MDOC_MAX] = {
+       { NULL, NULL },                         /* \" */
+       { pres_dd, posts_text },                /* Dd */
+       { pres_dt, NULL },                      /* Dt */
+       { pres_os, NULL },                      /* Os */
+       { pres_sh, posts_sh },                  /* Sh */ 
+       { pres_ss, posts_ss },                  /* Ss */ 
+       { NULL, posts_pp },                     /* Pp */ 
+       { pres_d1, posts_wline },               /* D1 */
+       { pres_d1, posts_wline },               /* Dl */
+       { pres_bd, posts_bd },                  /* Bd */
+       { NULL, NULL },                         /* Ed */
+       { pres_bl, posts_bl },                  /* Bl */ 
+       { NULL, NULL },                         /* El */
+       { pres_it, posts_it },                  /* It */
+       { NULL, posts_text },                   /* Ad */ 
+       { pres_an, posts_an },                  /* An */ 
+       { NULL, NULL },                         /* Ar */
+       { pres_cd, posts_text },                /* Cd */ 
+       { NULL, NULL },                         /* Cm */
+       { NULL, posts_text },                   /* Dv */ 
+       { pres_er, posts_text },                /* Er */ 
+       { NULL, posts_text },                   /* Ev */ 
+       { pres_ex, posts_ex },                  /* Ex */ 
+       { NULL, posts_text },                   /* Fa */ 
+       { pres_fd, posts_fd },                  /* Fd */
+       { NULL, NULL },                         /* Fl */
+       { NULL, posts_text },                   /* Fn */ 
+       { NULL, posts_wtext },                  /* Ft */ 
+       { NULL, posts_text },                   /* Ic */ 
+       { NULL, posts_in },                     /* In */ 
+       { NULL, posts_text },                   /* Li */
+       { NULL, posts_wtext },                  /* Nd */
+       { NULL, posts_nm },                     /* Nm */
+       { NULL, posts_wline },                  /* Op */
+       { NULL, NULL },                         /* Ot */
+       { NULL, NULL },                         /* Pa */
+       { pres_rv, posts_notext },              /* Rv */
+       { NULL, posts_st },                     /* St */ 
+       { NULL, posts_text },                   /* Va */
+       { NULL, posts_text },                   /* Vt */ 
+       { NULL, posts_xr },                     /* Xr */ 
+       { NULL, posts_text },                   /* %A */
+       { NULL, posts_text },                   /* %B */
+       { NULL, posts_text },                   /* %D */
+       { NULL, posts_text },                   /* %I */
+       { NULL, posts_text },                   /* %J */
+       { NULL, posts_text },                   /* %N */
+       { NULL, posts_text },                   /* %O */
+       { NULL, posts_text },                   /* %P */
+       { NULL, posts_text },                   /* %R */
+       { NULL, posts_text },                   /* %T */
+       { NULL, posts_text },                   /* %V */
+       { NULL, NULL },                         /* Ac */
+       { NULL, NULL },                         /* Ao */
+       { NULL, posts_wline },                  /* Aq */
+       { NULL, posts_at },                     /* At */ 
+       { NULL, NULL },                         /* Bc */
+       { NULL, posts_bf },                     /* Bf */
+       { NULL, NULL },                         /* Bo */
+       { NULL, posts_wline },                  /* Bq */
+       { NULL, NULL },                         /* Bsx */
+       { NULL, NULL },                         /* Bx */
+       { NULL, posts_bool },                   /* Db */
+       { NULL, NULL },                         /* Dc */
+       { NULL, NULL },                         /* Do */
+       { NULL, posts_wline },                  /* Dq */
+       { NULL, NULL },                         /* Ec */
+       { NULL, NULL },                         /* Ef */ 
+       { NULL, posts_text },                   /* Em */ 
+       { NULL, NULL },                         /* Eo */
+       { NULL, NULL },                         /* Fx */
+       { NULL, posts_text },                   /* Ms */ 
+       { NULL, posts_notext },                 /* No */
+       { NULL, posts_notext },                 /* Ns */
+       { NULL, NULL },                         /* Nx */
+       { NULL, NULL },                         /* Ox */
+       { NULL, NULL },                         /* Pc */
+       { NULL, posts_pf },                     /* Pf */
+       { NULL, NULL },                         /* Po */
+       { NULL, posts_wline },                  /* Pq */
+       { NULL, NULL },                         /* Qc */
+       { NULL, posts_wline },                  /* Ql */
+       { NULL, NULL },                         /* Qo */
+       { NULL, posts_wline },                  /* Qq */
+       { NULL, NULL },                         /* Re */
+       { NULL, posts_rs },                     /* Rs */
+       { NULL, NULL },                         /* Sc */
+       { NULL, NULL },                         /* So */
+       { NULL, posts_wline },                  /* Sq */
+       { NULL, posts_bool },                   /* Sm */ 
+       { NULL, posts_text },                   /* Sx */
+       { NULL, posts_text },                   /* Sy */
+       { NULL, posts_text },                   /* Tn */
+       { NULL, NULL },                         /* Ux */
+       { NULL, NULL },                         /* Xc */
+       { NULL, NULL },                         /* Xo */
+       { NULL, posts_fo },                     /* Fo */ 
+       { NULL, NULL },                         /* Fc */ 
+       { NULL, NULL },                         /* Oo */
+       { NULL, NULL },                         /* Oc */
+       { NULL, posts_bk },                     /* Bk */
+       { NULL, NULL },                         /* Ek */
+       { NULL, posts_notext },                 /* Bt */
+       { NULL, NULL },                         /* Hf */
+       { NULL, NULL },                         /* Fr */
+       { NULL, posts_notext },                 /* Ud */
+       { pres_lb, posts_lb },                  /* Lb */
+};
 
-static int
-mbuf_indent(struct md_valid *p)
+
+int
+mdoc_valid_pre(struct mdoc *mdoc, 
+               const struct mdoc_node *node)
 {
-       size_t           i;
+       v_pre           *p;
+       int              line, pos;
+       const char      *tp;
+
+       if (MDOC_TEXT == node->type) {
+               tp = node->string;
+               line = node->line;
+               pos = node->pos;
+               return(check_text(mdoc, line, pos, tp));
+       }
+
+       if ( ! check_args(mdoc, node))
+               return(0);
+       if (NULL == mdoc_valids[node->tok].pre)
+               return(1);
+       for (p = mdoc_valids[node->tok].pre; *p; p++)
+               if ( ! (*p)(mdoc, node)) 
+                       return(0);
+       return(1);
+}
 
-       assert(p->pos == 0);
 
-       for (i = 0; i < MIN(p->indent, INDENT); i++)
-               if ( ! md_buf_putstring(p->mbuf, "    "))
+int
+mdoc_valid_post(struct mdoc *mdoc)
+{
+       v_post          *p;
+
+       /*
+        * This check occurs after the macro's children have been filled
+        * in: postfix validation.  Since this happens when we're
+        * rewinding the scope tree, it's possible to have multiple
+        * invocations (as by design, for now), we set bit MDOC_VALID to
+        * indicate that we've validated.
+        */
+
+       if (MDOC_VALID & mdoc->last->flags)
+               return(1);
+       mdoc->last->flags |= MDOC_VALID;
+
+       if (MDOC_TEXT == mdoc->last->type)
+               return(1);
+       if (MDOC_ROOT == mdoc->last->type)
+               return(post_root(mdoc));
+
+       if (NULL == mdoc_valids[mdoc->last->tok].post)
+               return(1);
+       for (p = mdoc_valids[mdoc->last->tok].post; *p; p++)
+               if ( ! (*p)(mdoc)) 
                        return(0);
 
-       p->pos += i * INDENT;
        return(1);
 }
 
 
+#define        merr(m, t) nerr((m), (m)->last, (t))
 static int
-mbuf_newline(struct md_valid *p)
+nerr(struct mdoc *m, const struct mdoc_node *n, enum merr type)
 {
+       char             *p;
+       
+       p = NULL;
 
-       if ( ! md_buf_putchar(p->mbuf, '\n'))
-               return(0);
+       switch (type) {
+       case (ENESTDISP):
+               p = "displays may not be nested";
+               break;
+       case (EBOOL):
+               p = "expected boolean value";
+               break;
+       case (EARGREP):
+               p = "argument repeated";
+               break;
+       case (EMULTIDISP):
+               p = "multiple display types specified";
+               break;
+       case (EMULTILIST):
+               p = "multiple list types specified";
+               break;
+       case (ELISTTYPE):
+               p = "missing list type";
+               break;
+       case (EDISPTYPE):
+               p = "missing display type";
+               break;
+       case (ELINE):
+               p = "expected line arguments";
+               break;
+       case (ENOPROLOGUE):
+               p = "document has no prologue";
+               break;
+       case (ENODATA):
+               p = "document has no data";
+               break;
+       case (EATT):
+               p = "expected valid AT&T symbol";
+               break;
+       case (ENAME):
+               p = "default name not yet set";
+               break;
+       }
 
-       p->pos = 0;
-       return(1);
+       assert(p);
+       return(mdoc_nerr(m, n, p));
 }
 
 
+#define        mwarn(m, t) nwarn((m), (m)->last, (t))
 static int
-mbuf_data(struct md_valid *p, char *buf)
+nwarn(struct mdoc *m, const struct mdoc_node *n, enum mwarn type)
+{
+       char             *p;
+       enum mdoc_warn    c;
+
+       c = WARN_SYNTAX;
+       p = NULL;
+
+       switch (type) {
+       case (WBADMSEC):
+               p = "inappropriate manual section";
+               c = WARN_COMPAT;
+               break;
+       case (WBADSEC):
+               p = "inappropriate document section";
+               c = WARN_COMPAT;
+               break;
+       case (WARGVAL):
+               p = "argument value suggested";
+               c = WARN_COMPAT;
+               break;
+       case (WPROLREP):
+               p = "prologue macros repeated";
+               c = WARN_COMPAT;
+               break;
+       case (WPROLOOO):
+               p = "prologue macros out-of-order";
+               c = WARN_COMPAT;
+               break;
+       case (WNOLINE):
+               p = "suggested no line arguments";
+               break;
+       case (WLINE):
+               p = "suggested line arguments";
+               break;
+       case (WMULTILINE):
+               p = "suggested multi-line arguments";
+               break;
+       case (WNOMULTILINE):
+               p = "suggested no multi-line arguments";
+               break;
+       case (WWRONGMSEC):
+               p = "document section in wrong manual section";
+               c = WARN_COMPAT;
+               break;
+       case (WSECOOO):
+               p = "document section out of conventional order";
+               break;
+       case (WSECREP):
+               p = "document section repeated";
+               break;
+       case (WBADSTAND):
+               p = "unknown standard";
+               break;
+       case (WNAMESECINC):
+               p = "NAME section contents incomplete/badly-ordered";
+               break;
+       }
+       assert(p);
+       return(mdoc_nwarn(m, n, c, p));
+}
+
+
+
+static inline int
+warn_count(struct mdoc *m, const char *k, 
+               int want, const char *v, int has)
 {
-       int              space;
-       size_t           sz;
-       char            *bufp;
 
-       space = 1; /* FIXME */
+       return(mdoc_warn(m, WARN_SYNTAX, 
+               "suggests %s %s %d (has %d)", v, k, want, has));
+}
 
-       assert(p->mbuf);
-       assert(0 != p->indent);
 
-       if (MD_LITERAL & p->flags)
-               return(md_buf_putstring(p->mbuf, buf));
+static inline int
+err_count(struct mdoc *m, const char *k,
+               int want, const char *v, int has)
+{
 
-       while (*buf) {
-               while (*buf && isspace(*buf))
-                       buf++;
+       return(mdoc_err(m, 
+               "requires %s %s %d (has %d)", v, k, want, has));
+}
 
-               if (0 == *buf)
-                       break;
 
-               bufp = buf;
-               while (*buf && ! isspace(*buf))
-                       buf++;
+static inline int
+count_child(struct mdoc *mdoc)
+{
+       int               i;
+       struct mdoc_node *n;
 
-               if (0 != *buf)
-                       *buf++ = 0;
+       for (i = 0, n = mdoc->last->child; n; n = n->next, i++)
+               /* Do nothing */ ;
 
-               /* Process word. */
+       return(i);
+}
 
-               sz = strlen(bufp);
 
-               if (0 == p->pos) {
-                       if ( ! mbuf_indent(p))
-                               return(0);
-                       if ( ! md_buf_putstring(p->mbuf, bufp))
-                               return(0);
+/*
+ * Build these up with macros because they're basically the same check
+ * for different inequalities.  Yes, this could be done with functions,
+ * but this is reasonable for now.
+ */
+
+#define CHECK_CHILD_DEFN(lvl, name, ineq)                      \
+static int                                                     \
+lvl##_child_##name(struct mdoc *mdoc, const char *p, int sz)   \
+{                                                              \
+       int i;                                                  \
+       if ((i = count_child(mdoc)) ineq sz)                    \
+               return(1);                                      \
+       return(lvl##_count(mdoc, #ineq, sz, p, i));             \
+}
+
+#define CHECK_BODY_DEFN(name, lvl, func, num)                  \
+static int                                                     \
+b##lvl##_##name(POST_ARGS)                                     \
+{                                                              \
+       if (MDOC_BODY != mdoc->last->type)                      \
+               return(1);                                      \
+       return(func(mdoc, "multi-line arguments", (num)));      \
+}
+
+#define CHECK_ELEM_DEFN(name, lvl, func, num)                  \
+static int                                                     \
+e##lvl##_##name(POST_ARGS)                                     \
+{                                                              \
+       assert(MDOC_ELEM == mdoc->last->type);                  \
+       return(func(mdoc, "line arguments", (num)));            \
+}
+
+#define CHECK_HEAD_DEFN(name, lvl, func, num)                  \
+static int                                                     \
+h##lvl##_##name(POST_ARGS)                                     \
+{                                                              \
+       if (MDOC_HEAD != mdoc->last->type)                      \
+               return(1);                                      \
+       return(func(mdoc, "line arguments", (num)));            \
+}
+
+
+CHECK_CHILD_DEFN(warn, gt, >)                  /* warn_child_gt() */
+CHECK_CHILD_DEFN(err, gt, >)                   /* err_child_gt() */
+CHECK_CHILD_DEFN(warn, eq, ==)                 /* warn_child_eq() */
+CHECK_CHILD_DEFN(err, eq, ==)                  /* err_child_eq() */
+CHECK_CHILD_DEFN(err, lt, <)                   /* err_child_lt() */
+CHECK_CHILD_DEFN(warn, lt, <)                  /* warn_child_lt() */
+CHECK_BODY_DEFN(ge1, warn, warn_child_gt, 0)   /* bwarn_ge1() */
+CHECK_ELEM_DEFN(eq1, warn, warn_child_eq, 1)   /* ewarn_eq1() */
+CHECK_ELEM_DEFN(eq0, warn, warn_child_eq, 0)   /* ewarn_eq0() */
+CHECK_ELEM_DEFN(ge1, warn, warn_child_gt, 0)   /* ewarn_gt1() */
+CHECK_ELEM_DEFN(eq1, err, err_child_eq, 1)     /* eerr_eq1() */
+CHECK_ELEM_DEFN(le2, err, err_child_lt, 3)     /* eerr_le2() */
+CHECK_ELEM_DEFN(eq0, err, err_child_eq, 0)     /* eerr_eq0() */
+CHECK_ELEM_DEFN(ge1, err, err_child_gt, 0)     /* eerr_ge1() */
+CHECK_HEAD_DEFN(eq0, err, err_child_eq, 0)     /* herr_eq0() */
+CHECK_HEAD_DEFN(le1, warn, warn_child_lt, 2)   /* hwarn_le1() */
+CHECK_HEAD_DEFN(ge1, err, err_child_gt, 0)     /* herr_ge1() */
+CHECK_HEAD_DEFN(eq1, warn, warn_child_eq, 1)   /* hwarn_eq1() */
+
+
+static int
+check_stdarg(PRE_ARGS)
+{
+
+       if (n->args && 1 == n->args->argc)
+               if (MDOC_Std == n->args->argv[0].arg)
+                       return(1);
+       return(nwarn(mdoc, n, WARGVAL));
+}
 
-                       if (p->indent * INDENT + sz >= 72) {
-                               if ( ! mbuf_newline(p))
-                                       return(0);
-                               continue;
-                       }
 
-                       p->pos += sz;
+static int
+check_sec(PRE_ARGS, ...)
+{
+       enum mdoc_sec    sec;
+       va_list          ap;
+
+       va_start(ap, n);
+
+       for (;;) {
+               /* LINTED */
+               sec = (enum mdoc_sec)va_arg(ap, int);
+               if (SEC_CUSTOM == sec)
+                       break;
+               if (sec != mdoc->lastsec)
                        continue;
-               }
+               va_end(ap);
+               return(1);
+       }
 
-               if (sz + p->pos >= 72) {
-                       if ( ! mbuf_newline(p))
-                               return(0);
-                       if ( ! mbuf_indent(p))
-                               return(0);
-               } else if (space) 
-                       if ( ! md_buf_putchar(p->mbuf, ' '))
-                               return(0);
+       va_end(ap);
+       return(nwarn(mdoc, n, WBADSEC));
+}
+
+
+static int
+check_msec(PRE_ARGS, ...)
+{
+       va_list          ap;
+       int              msec;
+
+       va_start(ap, n);
+       for (;;) {
+               /* LINTED */
+               if (0 == (msec = va_arg(ap, int)))
+                       break;
+               if (msec != mdoc->meta.msec)
+                       continue;
+               va_end(ap);
+               return(1);
+       }
+
+       va_end(ap);
+       return(nwarn(mdoc, n, WBADMSEC));
+}
 
-               if ( ! md_buf_putstring(p->mbuf, bufp))
+
+static int
+check_args(struct mdoc *m, const struct mdoc_node *n)
+{
+       int              i;
+
+       if (NULL == n->args)
+               return(1);
+
+       for (i = 0; i < (int)n->args->argc; i++)
+               if ( ! check_argv(m, n, &n->args->argv[i]))
                        return(0);
 
-               p->pos += sz + (space ? 1 : 0);
+       return(1);
+}
+
+
+static int
+check_argv(struct mdoc *m, const struct mdoc_node *n, 
+               const struct mdoc_argv *v)
+{
+       int              i;
+
+       for (i = 0; i < (int)v->sz; i++)
+               if ( ! check_text(m, v->line, v->pos, v->value[i]))
+                       return(0);
+
+       if (MDOC_Std == v->arg && MDOC_Ex == n->tok) {
+               /* `Nm' name must be set. */
+               if (v->sz || m->meta.name)
+                       return(1);
+               return(nerr(m, n, ENAME));
        }
 
        return(1);
 }
 
 
-int
-md_line_valid(void *arg, char *buf)
+static int
+check_text(struct mdoc *mdoc, int line, int pos, const char *p)
 {
-       struct md_valid *p;
+       size_t           c;
+
+       /* XXX - indicate deprecated escapes \*(xx and \*x. */
+
+       for ( ; *p; p++) {
+               if ( ! isprint((u_char)*p) && '\t' != *p)
+                       return(mdoc_perr(mdoc, line, pos,
+                               "invalid non-printing character"));
+               if ('\\' != *p)
+                       continue;
+               if ((c = mdoc_isescape(p))) {
+                       p += (int)c - 1;
+                       continue;
+               }
+               return(mdoc_perr(mdoc, line, pos, 
+                               "invalid escape sequence: %s", p));
+       }
 
-       p = (struct md_valid *)arg;
-       return(roff_engine(p->tree, buf));
+       return(1);
 }
 
 
-int
-md_exit_valid(void *data, int flush)
+
+
+static int
+check_parent(PRE_ARGS, int tok, enum mdoc_type t)
 {
-       int              c;
-       struct md_valid *p;
 
-       p = (struct md_valid *)data;
-       c = roff_free(p->tree, flush);
-       free(p);
+       assert(n->parent);
+       if ((MDOC_ROOT == t || tok == n->parent->tok) &&
+                       (t == n->parent->type))
+               return(1);
 
-       return(c);
+       return(mdoc_nerr(mdoc, n, "require parent %s",
+               MDOC_ROOT == t ? "<root>" : mdoc_macronames[tok]));
 }
 
 
-void *
-md_init_valid(const struct md_args *args,
-               struct md_mbuf *mbuf, const struct md_rbuf *rbuf)
+
+static int
+pre_display(PRE_ARGS)
 {
-       struct roffcb    cb;
-       struct md_valid *p;
+       struct mdoc_node *node;
 
-       cb.roffhead = roffhead;
-       cb.rofftail = rofftail;
-       cb.roffin = roffin;
-       cb.roffout = roffout;
-       cb.roffblkin = roffblkin;
-       cb.roffblkout = roffblkout;
-       cb.roffspecial = roffspecial;
-       cb.roffmsg = roffmsg;
-       cb.roffdata = roffdata;
+       /* Display elements (`Bd', `D1'...) cannot be nested. */
 
-       if (NULL == (p = calloc(1, sizeof(struct md_valid))))
-               err(1, "malloc");
+       if (MDOC_BLOCK != n->type)
+               return(1);
 
-       p->args = args;
-       p->mbuf = mbuf;
-       p->rbuf = rbuf;
+       /* LINTED */
+       for (node = mdoc->last->parent; node; node = node->parent) 
+               if (MDOC_BLOCK == node->type)
+                       if (MDOC_Bd == node->tok)
+                               break;
+       if (NULL == node)
+               return(1);
 
-       assert(mbuf);
+       return(nerr(mdoc, n, ENESTDISP));
+}
 
-       if (NULL == (p->tree = roff_alloc(&cb, p))) {
-               free(p);
-               return(NULL);
+
+static int
+pre_bl(PRE_ARGS)
+{
+       int              i, type, width, offset;
+
+       if (MDOC_BLOCK != n->type)
+               return(1);
+       if (NULL == n->args)
+               return(nerr(mdoc, n, ELISTTYPE));
+
+       /* Make sure that only one type of list is specified.  */
+
+       type = offset = width = -1;
+
+       /* LINTED */
+       for (i = 0; i < (int)n->args->argc; i++)
+               switch (n->args->argv[i].arg) {
+               case (MDOC_Bullet):
+                       /* FALLTHROUGH */
+               case (MDOC_Dash):
+                       /* FALLTHROUGH */
+               case (MDOC_Enum):
+                       /* FALLTHROUGH */
+               case (MDOC_Hyphen):
+                       /* FALLTHROUGH */
+               case (MDOC_Item):
+                       /* FALLTHROUGH */
+               case (MDOC_Tag):
+                       /* FALLTHROUGH */
+               case (MDOC_Diag):
+                       /* FALLTHROUGH */
+               case (MDOC_Hang):
+                       /* FALLTHROUGH */
+               case (MDOC_Ohang):
+                       /* FALLTHROUGH */
+               case (MDOC_Inset):
+                       /* FALLTHROUGH */
+               case (MDOC_Column):
+                       if (-1 == type) {
+                               type = n->args->argv[i].arg;
+                               break;
+                       }
+                       return(nerr(mdoc, n, EMULTILIST));
+               case (MDOC_Width):
+                       if (-1 == width) {
+                               width = n->args->argv[i].arg;
+                               break;
+                       }
+                       return(nerr(mdoc, n, EARGREP));
+               case (MDOC_Offset):
+                       if (-1 == offset) {
+                               offset = n->args->argv[i].arg;
+                               break;
+                       }
+                       return(nerr(mdoc, n, EARGREP));
+               default:
+                       break;
+               }
+
+       if (-1 == type)
+               return(nerr(mdoc, n, ELISTTYPE));
+
+       switch (type) {
+       case (MDOC_Column):
+               /* FALLTHROUGH */
+       case (MDOC_Diag):
+               /* FALLTHROUGH */
+       case (MDOC_Inset):
+               /* FALLTHROUGH */
+       case (MDOC_Item):
+               if (-1 == width)
+                       break;
+               return(mdoc_nwarn(mdoc, n, WARN_SYNTAX,
+                               "superfluous %s argument",
+                               mdoc_argnames[MDOC_Width]));
+       case (MDOC_Tag):
+               if (-1 != width)
+                       break;
+               return(mdoc_nerr(mdoc, n, "missing %s argument",
+                               mdoc_argnames[MDOC_Width]));
+       default:
+               break;
        }
 
-       return(p);
+       return(1);
 }
 
 
-/* ARGSUSED */
 static int
-roffhead(void *arg)
+pre_bd(PRE_ARGS)
 {
-       struct md_valid *p;
+       int              i, type, err;
+
+       if (MDOC_BLOCK != n->type)
+               return(1);
+       if (NULL == n->args) 
+               return(nerr(mdoc, n, EDISPTYPE));
+
+       /* Make sure that only one type of display is specified.  */
+
+       /* LINTED */
+       for (i = 0, err = type = 0; ! err && 
+                       i < (int)n->args->argc; i++)
+               switch (n->args->argv[i].arg) {
+               case (MDOC_Ragged):
+                       /* FALLTHROUGH */
+               case (MDOC_Unfilled):
+                       /* FALLTHROUGH */
+               case (MDOC_Filled):
+                       /* FALLTHROUGH */
+               case (MDOC_Literal):
+                       /* FALLTHROUGH */
+               case (MDOC_File):
+                       if (0 == type++) 
+                               break;
+                       return(nerr(mdoc, n, EMULTIDISP));
+               default:
+                       break;
+               }
 
-       assert(arg);
-       p = (struct md_valid *)arg;
+       if (type)
+               return(1);
+       return(nerr(mdoc, n, EDISPTYPE));
+}
 
-       if ( ! md_buf_putstring(p->mbuf, "BEGIN"))
-               return(0);
-       p->indent++;
-       if ( ! mbuf_newline(p))
-               return(0);
 
-       return(1);
+static int
+pre_ss(PRE_ARGS)
+{
+
+       if (MDOC_BLOCK != n->type)
+               return(1);
+       return(check_parent(mdoc, n, MDOC_Sh, MDOC_BODY));
+}
+
+
+static int
+pre_sh(PRE_ARGS)
+{
+
+       if (MDOC_BLOCK != n->type)
+               return(1);
+       return(check_parent(mdoc, n, -1, MDOC_ROOT));
+}
+
+
+static int
+pre_it(PRE_ARGS)
+{
+
+       if (MDOC_BLOCK != n->type)
+               return(1);
+       return(check_parent(mdoc, n, MDOC_Bl, MDOC_BODY));
 }
 
 
 static int
-rofftail(void *arg)
+pre_an(PRE_ARGS)
 {
-       struct md_valid *p;
 
-       assert(arg);
-       p = (struct md_valid *)arg;
+       if (n->args && 1 >= n->args->argc)
+               return(1);
+       return(mdoc_nerr(mdoc, n, "only one argument allowed"));
+}
+
 
-       if (0 != p->pos && ! mbuf_newline(p))
+static int
+pre_lb(PRE_ARGS)
+{
+
+       return(check_sec(mdoc, n, SEC_LIBRARY, SEC_CUSTOM));
+}
+
+
+static int
+pre_rv(PRE_ARGS)
+{
+
+       if ( ! check_msec(mdoc, n, 2, 3, 0))
                return(0);
+       return(check_stdarg(mdoc, n));
+}
+
+
+static int
+pre_ex(PRE_ARGS)
+{
 
-       if ( ! md_buf_putstring(p->mbuf, "END\n"))
+       if ( ! check_msec(mdoc, n, 1, 6, 8, 0))
                return(0);
-       return(1);
+       return(check_stdarg(mdoc, n));
+}
+
+
+static int
+pre_er(PRE_ARGS)
+{
+
+       return(check_msec(mdoc, n, 2, 0));
 }
 
 
 static int
-roffspecial(void *arg, int tok)
+pre_cd(PRE_ARGS)
 {
 
+       return(check_msec(mdoc, n, 4, 0));
+}
+
+
+static int
+pre_prologue(PRE_ARGS)
+{
+
+       return(check_sec(mdoc, n, SEC_PROLOGUE, SEC_CUSTOM));
+}
+
+
+static int
+pre_dt(PRE_ARGS)
+{
+
+       if (0 == mdoc->meta.date || mdoc->meta.os)
+               if ( ! nwarn(mdoc, n, WPROLOOO))
+                       return(0);
+       if (mdoc->meta.title)
+               if ( ! nwarn(mdoc, n, WPROLREP))
+                       return(0);
        return(1);
 }
 
 
 static int
-roffblkin(void *arg, int tok, int *argc, char **argv)
+pre_os(PRE_ARGS)
 {
-       struct md_valid *p;
 
-       assert(arg);
-       p = (struct md_valid *)arg;
+       if (NULL == mdoc->meta.title || 0 == mdoc->meta.date)
+               if ( ! nwarn(mdoc, n, WPROLOOO))
+                       return(0);
+       if (mdoc->meta.os)
+               if ( ! nwarn(mdoc, n, WPROLREP))
+                       return(0);
+       return(1);
+}
+
+
+static int
+pre_dd(PRE_ARGS)
+{
 
-       if (0 != p->pos) {
-               if ( ! mbuf_newline(p))
+       if (mdoc->meta.title || mdoc->meta.os)
+               if ( ! nwarn(mdoc, n, WPROLOOO))
                        return(0);
-               if ( ! mbuf_indent(p))
+       if (mdoc->meta.date)
+               if ( ! nwarn(mdoc, n, WPROLREP))
                        return(0);
-       } else if ( ! mbuf_indent(p))
-               return(0);
+       return(1);
+}
 
-       if ( ! md_buf_putchar(p->mbuf, '<'))
-               return(0);
-       if ( ! md_buf_putstring(p->mbuf, toknames[tok]))
-               return(0);
-       if ( ! md_buf_putchar(p->mbuf, '>'))
-               return(0);
-       if ( ! mbuf_newline(p))
-               return(0);
 
-       p->indent++;
+static int
+post_bf(POST_ARGS)
+{
+       char             *p;
+       struct mdoc_node *head;
+
+       if (MDOC_BLOCK != mdoc->last->type)
+               return(1);
+
+       head = mdoc->last->head;
+
+       if (NULL == mdoc->last->args) {
+               if (NULL == head->child || 
+                               MDOC_TEXT != head->child->type)
+                       return(mdoc_err(mdoc, "text argument expected"));
+
+               p = head->child->string;
+               if (xstrcmp(p, "Em"))
+                       return(1);
+               else if (xstrcmp(p, "Li"))
+                       return(1);
+               else if (xstrcmp(p, "Sm"))
+                       return(1);
+               return(mdoc_nerr(mdoc, head->child, "invalid font"));
+       }
+
+       if (head->child)
+               return(mdoc_err(mdoc, "one argument expected"));
+
        return(1);
 }
 
 
 static int
-roffblkout(void *arg, int tok)
+post_nm(POST_ARGS)
 {
-       struct md_valid *p;
 
-       assert(arg);
-       p = (struct md_valid *)arg;
+       if (mdoc->last->child)
+               return(1);
+       if (mdoc->meta.name)
+               return(1);
+       return(merr(mdoc, ENAME));
+}
 
-       p->indent--;
 
-       if (0 != p->pos) {
-               if ( ! mbuf_newline(p))
-                       return(0);
-               if ( ! mbuf_indent(p))
+static int
+post_at(POST_ARGS)
+{
+
+       if (NULL == mdoc->last->child)
+               return(1);
+       if (MDOC_TEXT != mdoc->last->child->type)
+               return(merr(mdoc, EATT));
+       if (mdoc_a2att(mdoc->last->child->string))
+               return(1);
+       return(merr(mdoc, EATT));
+}
+
+
+static int
+post_an(POST_ARGS)
+{
+
+       if (mdoc->last->args) {
+               if (NULL == mdoc->last->child)
+                       return(1);
+               return(merr(mdoc, ELINE));
+       }
+
+       if (mdoc->last->child)
+               return(1);
+       return(merr(mdoc, ELINE));
+}
+
+
+static int
+post_ex(POST_ARGS)
+{
+
+       if (mdoc->last->args)
+               return(1);
+       return(merr(mdoc, ELINE));
+}
+
+
+static int
+post_it(POST_ARGS)
+{
+       int               type, i, cols;
+       struct mdoc_node *n, *c;
+
+       if (MDOC_BLOCK != mdoc->last->type)
+               return(1);
+
+       n = mdoc->last->parent->parent;
+       if (NULL == n->args)
+               return(merr(mdoc, ELISTTYPE));
+
+       /* Some types require block-head, some not. */
+
+       /* LINTED */
+       for (cols = type = -1, i = 0; -1 == type && 
+                       i < (int)n->args->argc; i++)
+               switch (n->args->argv[i].arg) {
+               case (MDOC_Tag):
+                       /* FALLTHROUGH */
+               case (MDOC_Diag):
+                       /* FALLTHROUGH */
+               case (MDOC_Hang):
+                       /* FALLTHROUGH */
+               case (MDOC_Ohang):
+                       /* FALLTHROUGH */
+               case (MDOC_Inset):
+                       /* FALLTHROUGH */
+               case (MDOC_Bullet):
+                       /* FALLTHROUGH */
+               case (MDOC_Dash):
+                       /* FALLTHROUGH */
+               case (MDOC_Enum):
+                       /* FALLTHROUGH */
+               case (MDOC_Hyphen):
+                       /* FALLTHROUGH */
+               case (MDOC_Item):
+                       type = n->args->argv[i].arg;
+                       break;
+               case (MDOC_Column):
+                       type = n->args->argv[i].arg;
+                       cols = (int)n->args->argv[i].sz;
+                       break;
+               default:
+                       break;
+               }
+
+       if (-1 == type)
+               return(merr(mdoc, ELISTTYPE));
+
+       switch (type) {
+       case (MDOC_Tag):
+               if (NULL == mdoc->last->head->child)
+                       if ( ! mwarn(mdoc, WLINE))
+                               return(0);
+               break;
+       case (MDOC_Hang):
+               /* FALLTHROUGH */
+       case (MDOC_Ohang):
+               /* FALLTHROUGH */
+       case (MDOC_Inset):
+               /* FALLTHROUGH */
+       case (MDOC_Diag):
+               if (NULL == mdoc->last->head->child)
+                       if ( ! mwarn(mdoc, WLINE))
+                               return(0);
+               if (NULL == mdoc->last->body->child)
+                       if ( ! mwarn(mdoc, WMULTILINE))
+                               return(0);
+               break;
+       case (MDOC_Bullet):
+               /* FALLTHROUGH */
+       case (MDOC_Dash):
+               /* FALLTHROUGH */
+       case (MDOC_Enum):
+               /* FALLTHROUGH */
+       case (MDOC_Hyphen):
+               /* FALLTHROUGH */
+       case (MDOC_Item):
+               if (mdoc->last->head->child)
+                       if ( ! mwarn(mdoc, WNOLINE))
+                               return(0);
+               if (NULL == mdoc->last->body->child)
+                       if ( ! mwarn(mdoc, WMULTILINE))
+                               return(0);
+               break;
+       case (MDOC_Column):
+               if (NULL == mdoc->last->head->child)
+                       if ( ! mwarn(mdoc, WLINE))
+                               return(0);
+               if (mdoc->last->body->child)
+                       if ( ! mwarn(mdoc, WNOMULTILINE))
+                               return(0);
+               c = mdoc->last->head->child;
+               for (i = 0; c; c = c->next)
+                       i++;
+               if (i == cols)
+                       break;
+               if ( ! mdoc_warn(mdoc, WARN_SYNTAX, 
+                                       "column mismatch (have %d, want %d)", i, cols))
                        return(0);
-       } else if ( ! mbuf_indent(p))
-               return(0);
+               break;
+       default:
+               break;
+       }
 
-       if ( ! md_buf_putstring(p->mbuf, "</"))
-               return(0);
-       if ( ! md_buf_putstring(p->mbuf, toknames[tok]))
-               return(0);
-       if ( ! md_buf_putstring(p->mbuf, ">"))
-               return(0);
-       if ( ! mbuf_newline(p))
-               return(0);
+       return(1);
+}
+
+
+static int
+post_bl(POST_ARGS)
+{
+       struct mdoc_node        *n;
+
+       if (MDOC_BODY != mdoc->last->type)
+               return(1);
+       if (NULL == mdoc->last->child)
+               return(1);
+
+       /* LINTED */
+       for (n = mdoc->last->child; n; n = n->next) {
+               if (MDOC_BLOCK == n->type) 
+                       if (MDOC_It == n->tok)
+                               continue;
+               return(mdoc_nerr(mdoc, n, "bad child of parent %s",
+                               mdoc_macronames[mdoc->last->tok]));
+       }
 
        return(1);
 }
 
 
 static int
-roffin(void *arg, int tok, int *argcp, char **argvp)
+ebool(struct mdoc *mdoc)
 {
-       struct md_valid *p;
+       struct mdoc_node *n;
 
-       assert(arg);
-       p = (struct md_valid *)arg;
+       /* LINTED */
+       for (n = mdoc->last->child; n; n = n->next) {
+               if (MDOC_TEXT != n->type)
+                       break;
+               if (xstrcmp(n->string, "on"))
+                       continue;
+               if (xstrcmp(n->string, "off"))
+                       continue;
+               break;
+       }
 
-       if (0 == p->pos && ! mbuf_indent(p))
-               return(0);
+       if (NULL == n)
+               return(1);
+       return(nerr(mdoc, n, EBOOL));
+}
 
-       if ( ! md_buf_putstring(p->mbuf, " <"))
-               return(0);
-       if ( ! md_buf_putstring(p->mbuf, toknames[tok]))
-               return(0);
-       if ( ! md_buf_putstring(p->mbuf, ">"))
-               return(0);
 
-       p->pos += strlen(toknames[tok]) + 3;
+static int
+post_root(POST_ARGS)
+{
+
+       if (NULL == mdoc->first->child)
+               return(merr(mdoc, ENODATA));
+       if (SEC_PROLOGUE == mdoc->lastnamed)
+               return(merr(mdoc, ENOPROLOGUE));
+
+       if (MDOC_BLOCK != mdoc->first->child->type)
+               return(merr(mdoc, ENODATA));
+       if (MDOC_Sh != mdoc->first->child->tok)
+               return(merr(mdoc, ENODATA));
 
        return(1);
 }
 
 
 static int
-roffout(void *arg, int tok)
+post_st(POST_ARGS)
 {
-       struct md_valid *p;
 
-       assert(arg);
-       p = (struct md_valid *)arg;
+       if (mdoc_a2st(mdoc->last->child->string))
+               return(1);
+       return(mwarn(mdoc, WBADSTAND));
+}
 
-       if (0 == p->pos && ! mbuf_indent(p))
-               return(0);
 
-       if ( ! md_buf_putstring(p->mbuf, "</"))
-               return(0);
-       if ( ! md_buf_putstring(p->mbuf, toknames[tok]))
-               return(0);
-       if ( ! md_buf_putstring(p->mbuf, ">"))
-               return(0);
+static int
+post_sh(POST_ARGS)
+{
 
-       p->pos += strlen(toknames[tok]) + 2;
+       if (MDOC_HEAD == mdoc->last->type)
+               return(post_sh_head(mdoc));
+       if (MDOC_BODY == mdoc->last->type)
+               return(post_sh_body(mdoc));
 
        return(1);
 }
 
 
+static int
+post_sh_body(POST_ARGS)
+{
+       struct mdoc_node *n;
+
+       if (SEC_NAME != mdoc->lastnamed)
+               return(1);
+
+       /*
+        * Warn if the NAME section doesn't contain the `Nm' and `Nd'
+        * macros (can have multiple `Nm' and one `Nd').  Note that the
+        * children of the BODY declaration can also be "text".
+        */
+
+       if (NULL == (n = mdoc->last->child))
+               return(mwarn(mdoc, WNAMESECINC));
+
+       for ( ; n && n->next; n = n->next) {
+               if (MDOC_ELEM == n->type && MDOC_Nm == n->tok)
+                       continue;
+               if (MDOC_TEXT == n->type)
+                       continue;
+               if ( ! mwarn(mdoc, WNAMESECINC))
+                       return(0);
+       }
+
+       if (MDOC_ELEM == n->type && MDOC_Nd == n->tok)
+               return(1);
+       return(mwarn(mdoc, WNAMESECINC));
+}
+
 
-static void
-roffmsg(void *arg, enum roffmsg lvl, 
-               const char *buf, const char *pos, char *msg)
+static int
+post_sh_head(POST_ARGS)
 {
-       char            *level;
-       struct md_valid *p;
+       char              buf[64];
+       enum mdoc_sec     sec;
 
-       assert(arg);
-       p = (struct md_valid *)arg;
+       /*
+        * Process a new section.  Sections are either "named" or
+        * "custom"; custom sections are user-defined, while named ones
+        * usually follow a conventional order and may only appear in
+        * certain manual sections.
+        */
 
-       switch (lvl) {
-       case (ROFF_WARN):
-               if ( ! (MD_WARN_ALL & p->args->warnings))
-                       return;
-               level = "warning";
-               break;
-       case (ROFF_ERROR):
-               level = "error";
+       assert(MDOC_Sh == mdoc->last->tok);
+
+       (void)xstrlcpys(buf, mdoc->last->child, sizeof(buf));
+
+       sec = mdoc_atosec(buf);
+
+       /* The NAME section should always be first. */
+
+       if (SEC_BODY == mdoc->lastnamed && SEC_NAME != sec)
+               return(mwarn(mdoc, WSECOOO));
+       if (SEC_CUSTOM == sec)
+               return(1);
+
+       /* Check for repeated or out-of-order sections. */
+
+       if (sec == mdoc->lastnamed)
+               return(mwarn(mdoc, WSECREP));
+       if (sec < mdoc->lastnamed)
+               return(mwarn(mdoc, WSECOOO));
+
+       /* Check particular section/manual section conventions. */
+
+       switch (sec) {
+       case (SEC_LIBRARY):
+               switch (mdoc->meta.msec) {
+               case (2):
+                       /* FALLTHROUGH */
+               case (3):
+                       break;
+               default:
+                       return(mwarn(mdoc, WWRONGMSEC));
+               }
                break;
        default:
-               abort();
+               break;
        }
-       
-       if (pos)
-               (void)fprintf(stderr, "%s:%zu: %s: %s\n", 
-                               p->rbuf->name, p->rbuf->line, level, msg);
-       else
-               (void)fprintf(stderr, "%s: %s: %s\n", 
-                               p->rbuf->name, level, msg);
 
+       return(1);
 }
 
 
 static int
-roffdata(void *arg, char *buf)
+pre_fd(PRE_ARGS)
 {
-       struct md_valid *p;
 
-       assert(arg);
-       p = (struct md_valid *)arg;
-       return(mbuf_data(p, buf));
+       return(check_sec(mdoc, n, SEC_SYNOPSIS, SEC_CUSTOM));
 }