Outside explicit font context, give every letter its own box.

The formatters need this to correctly select fonts.
Missing feature reported by bentley@.

diff --git a/usr.bin/mandoc/eqn.c b/usr.bin/mandoc/eqn.c
index 4edb03c..071bb8e 100644 (file)
--- a/usr.bin/mandoc/eqn.c
+++ b/usr.bin/mandoc/eqn.c
@@ -1,4 +1,4 @@
-/*     $OpenBSD: eqn.c,v 1.28 2017/06/21 18:37:38 schwarze Exp $ */
+/*     $OpenBSD: eqn.c,v 1.29 2017/06/21 20:47:46 schwarze Exp $ */
 /*
  * Copyright (c) 2011, 2014 Kristaps Dzonsons <kristaps@bsd.lv>
  * Copyright (c) 2014, 2015, 2017 Ingo Schwarze <schwarze@openbsd.org>
@@ -18,6 +18,7 @@
 #include <sys/types.h>
 
 #include <assert.h>
+#include <ctype.h>
 #include <limits.h>
 #include <stdio.h>
 #include <stdlib.h>
@@ -716,8 +717,8 @@ static enum rofferr
 eqn_parse(struct eqn_node *ep, struct eqn_box *parent)
 {
        char             sym[64];
-       struct eqn_box  *cur;
-       const char      *start;
+       struct eqn_box  *cur, *fontp, *nbox;
+       const char      *cp, *cpn, *start;
        char            *p;
        size_t           sz;
        enum eqn_tok     tok, subtok;
@@ -1090,21 +1091,51 @@ this_tok:
                 */
                while (parent->args == parent->expectargs)
                        parent = parent->parent;
-               if (tok == EQN_TOK_FUNC) {
-                       for (cur = parent; cur != NULL; cur = cur->parent)
-                               if (cur->font != EQNFONT_NONE)
-                                       break;
-                       if (cur == NULL || cur->font != EQNFONT_ROMAN) {
-                               parent = eqn_box_alloc(ep, parent);
-                               parent->type = EQN_LISTONE;
-                               parent->font = EQNFONT_ROMAN;
-                               parent->expectargs = 1;
-                       }
+               /*
+                * Wrap well-known function names in a roman box,
+                * unless they already are in roman context.
+                */
+               for (fontp = parent; fontp != NULL; fontp = fontp->parent)
+                       if (fontp->font != EQNFONT_NONE)
+                               break;
+               if (tok == EQN_TOK_FUNC &&
+                   (fontp == NULL || fontp->font != EQNFONT_ROMAN)) {
+                       parent = fontp = eqn_box_alloc(ep, parent);
+                       parent->type = EQN_LISTONE;
+                       parent->font = EQNFONT_ROMAN;
+                       parent->expectargs = 1;
                }
                cur = eqn_box_alloc(ep, parent);
                cur->type = EQN_TEXT;
                cur->text = p;
-
+               /*
+                * If not inside any explicit font context,
+                * give every letter its own box.
+                */
+               if (fontp == NULL && *p != '\0') {
+                       cp = p;
+                       for (;;) {
+                               cpn = cp + 1;
+                               if (*cp == '\\')
+                                       mandoc_escape(&cpn, NULL, NULL);
+                               if (*cpn == '\0')
+                                       break;
+                               if (isalpha((unsigned char)*cp) == 0 &&
+                                   isalpha((unsigned char)*cpn) == 0) {
+                                       cp = cpn;
+                                       continue;
+                               }
+                               nbox = eqn_box_alloc(ep, parent);
+                               nbox->type = EQN_TEXT;
+                               nbox->text = mandoc_strdup(cpn);
+                               p = mandoc_strndup(cur->text,
+                                   cpn - cur->text);
+                               free(cur->text);
+                               cur->text = p;
+                               cur = nbox;
+                               cp = nbox->text;
+                       }
+               }
                /*
                 * Post-process list status.
                 */