Replace "Grandfather" with a description of the relevant heuristic

In April 2003 commit f2095865e3489f4e:
    Noted by Nat: -0 didn't work that well with Unicode.

added support for passing hexadecimal to the -0 option. As '-0' has an
optional argument, the chosen syntax for hex was ambiguous with '-0' clustered
with an '-x' option with an argument, so the heuristic described here was
implemented.

1 files changed, 10 insertions, 1 deletions

diff --git a/perl.c b/perl.c
index 8beb5d0622..637e6b4196 100644
--- a/perl.c
+++ b/perl.c
@@ -3447,7 +3447,16 @@ Perl_moreswitches(pTHX_ const char *s)
               flags = PERL_SCAN_SILENT_ILLDIGIT;
               rschar = (U32)grok_hex(s, &numlen, &flags, NULL);
               if (s + numlen < e) {
-                   rschar = 0; /* Grandfather -0xFOO as -0 -xFOO. */
+                  /* Continue to treat -0xFOO as -0 -xFOO
+                   * (ie NUL as the input record separator, and -x with FOO
+                   *  as the directory argument)
+                   *
+                   * hex support for -0 was only added in 5.8.1, hence this
+                   * heuristic to distinguish between it and '-0' clustered with
+                   * '-x' with an argument. The text following '-0x' is only
+                   * processed as the IRS specified in hexadecimal if all
+                   * characters are valid hex digits. */
+                   rschar = 0;
                    numlen = 0;
                    s--;
               }