builtin-grep: support -w (--word-regexp).

Signed-off-by: Junio C Hamano <junkio@cox.net>

diff --git a/builtin-grep.c b/builtin-grep.c
index f1800a5..09e3677 100644 (file)
--- a/builtin-grep.c
+++ b/builtin-grep.c
@@ -89,6 +89,7 @@ struct grep_opt {
        unsigned invert:1;
        unsigned name_only:1;
        unsigned count:1;
+       unsigned word_regexp:1;
        int regflags;
        unsigned pre_context;
        unsigned post_context;
@@ -128,6 +129,11 @@ static char *end_of_line(char *cp, unsigned long *left)
        return cp;
 }
 
+static int word_char(char ch)
+{
+       return isalnum(ch) || ch == '_';
+}
+
 static void show_line(struct grep_opt *opt, const char *bol, const char *eol,
                      const char *name, unsigned lno, char sign)
 {
@@ -171,6 +177,25 @@ static int grep_buffer(struct grep_opt *opt, const char *name,
                        regex_t *exp = &p->regexp;
                        hit = !regexec(exp, bol, ARRAY_SIZE(pmatch),
                                       pmatch, 0);
+
+                       if (hit && opt->word_regexp) {
+                               /* Match beginning must be either
+                                * beginning of the line, or at word
+                                * boundary (i.e. the last char must
+                                * not be alnum or underscore).
+                                */
+                               if ((pmatch[0].rm_so < 0) ||
+                                   (eol - bol) <= pmatch[0].rm_so ||
+                                   (pmatch[0].rm_eo < 0) ||
+                                   (eol - bol) < pmatch[0].rm_eo)
+                                       die("regexp returned nonsense");
+                               if (pmatch[0].rm_so != 0 &&
+                                   word_char(bol[pmatch[0].rm_so-1]))
+                                       continue; /* not a word boundary */
+                               if ((eol-bol) < pmatch[0].rm_eo &&
+                                   word_char(bol[pmatch[0].rm_eo]))
+                                       continue; /* not a word boundary */
+                       }
                        if (hit)
                                break;
                }
@@ -461,6 +486,11 @@ int cmd_grep(int argc, const char **argv, char **envp)
                        opt.count = 1;
                        continue;
                }
+               if (!strcmp("-w", arg) ||
+                   !strcmp("--word-regexp", arg)) {
+                       opt.word_regexp = 1;
+                       continue;
+               }
                if (!strncmp("-A", arg, 2) ||
                    !strncmp("-B", arg, 2) ||
                    !strncmp("-C", arg, 2) ||