Change xdl_merge to generate output even for null merges

diff --git a/grep.c b/grep.c
index 706351197fc26efa10c4666d38433f8fbdf1d6b5..a4edacad8b4e4365bc22266521e26f3b617d53b5 100644 (file)
--- a/grep.c
+++ b/grep.c
@@ -54,6 +54,8 @@ static struct grep_expr *compile_pattern_atom(struct grep_pat **list)
        struct grep_expr *x;
 
        p = *list;
+       if (!p)
+               return NULL;
        switch (p->token) {
        case GREP_PATTERN: /* atom */
        case GREP_PATTERN_HEAD:
@@ -66,8 +68,6 @@ static struct grep_expr *compile_pattern_atom(struct grep_pat **list)
        case GREP_OPEN_PAREN:
                *list = p->next;
                x = compile_pattern_or(list);
-               if (!x)
-                       return NULL;
                if (!*list || (*list)->token != GREP_CLOSE_PAREN)
                        die("unmatched parenthesis");
                *list = (*list)->next;
@@ -83,6 +83,8 @@ static struct grep_expr *compile_pattern_not(struct grep_pat **list)
        struct grep_expr *x;
 
        p = *list;
+       if (!p)
+               return NULL;
        switch (p->token) {
        case GREP_NOT:
                if (!p->next)
@@ -361,6 +363,8 @@ static int match_expr_eval(struct grep_opt *o,
 {
        int h = 0;
 
+       if (!x)
+               die("Not a valid grep expression");
        switch (x->node) {
        case GREP_NODE_ATOM:
                h = match_one_pattern(o, x->u.atom, bol, eol, ctx);
@@ -507,7 +511,7 @@ static int grep_buffer_1(struct grep_opt *opt, const char *name,
                                if (from <= last_shown)
                                        from = last_shown + 1;
                                if (last_shown && from != last_shown + 1)
-                                       printf(hunk_mark);
+                                       fputs(hunk_mark, stdout);
                                while (from < lno) {
                                        pcl = &prev[lno-from-1];
                                        show_line(opt, pcl->bol, pcl->eol,
@@ -517,7 +521,7 @@ static int grep_buffer_1(struct grep_opt *opt, const char *name,
                                last_shown = lno-1;
                        }
                        if (last_shown && lno != last_shown + 1)
-                               printf(hunk_mark);
+                               fputs(hunk_mark, stdout);
                        if (!opt->count)
                                show_line(opt, bol, eol, name, lno, ':');
                        last_shown = last_hit = lno;
@@ -528,7 +532,7 @@ static int grep_buffer_1(struct grep_opt *opt, const char *name,
                         * we need to show this line.
                         */
                        if (last_shown && lno != last_shown + 1)
-                               printf(hunk_mark);
+                               fputs(hunk_mark, stdout);
                        show_line(opt, bol, eol, name, lno, '-');
                        last_shown = lno;
                }