[src/trunk]: src/bin/sh NFC: changes to comments only - expand/add comments r...

[kre <kre%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/73a310f42c6e
branches:  trunk
changeset: 353613:73a310f42c6e
user:      kre <kre%NetBSD.org@localhost>
date:      Sun May 14 11:17:04 2017 +0000

description:
NFC: changes to comments only - expand/add comments relating to ${#...}
parsing, and all its peculiarities.

diffstat:

 bin/sh/parser.c |  17 +++++++++++------
 1 files changed, 11 insertions(+), 6 deletions(-)

diffs (49 lines):

diff -r d709c38f5d71 -r 73a310f42c6e bin/sh/parser.c
--- a/bin/sh/parser.c   Sun May 14 10:57:32 2017 +0000
+++ b/bin/sh/parser.c   Sun May 14 11:17:04 2017 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: parser.c,v 1.127 2017/05/11 15:07:37 kre Exp $ */
+/*     $NetBSD: parser.c,v 1.128 2017/05/14 11:17:04 kre Exp $ */
 
 /*-
  * Copyright (c) 1991, 1993
@@ -37,7 +37,7 @@
 #if 0
 static char sccsid[] = "@(#)parser.c   8.7 (Berkeley) 5/16/95";
 #else
-__RCSID("$NetBSD: parser.c,v 1.127 2017/05/11 15:07:37 kre Exp $");
+__RCSID("$NetBSD: parser.c,v 1.128 2017/05/14 11:17:04 kre Exp $");
 #endif
 #endif /* not lint */
 
@@ -1754,8 +1754,12 @@
                                        subtype = VSLENGTH;
                                else if (is_special(c)) {
                                        /*
+                                        * ${#} is $# - the number of sh params
                                         * ${##} is the length of ${#}
+                                        * ${###} is ${#} with as much nothing
+                                        *        as possible removed from start
                                         * ${##1} is ${#} with leading 1 gone
+                                        * ${##\#} is ${#} with leading # gone
                                         *
                                         * this stuff is UGLY!
                                         */
@@ -1764,12 +1768,13 @@
                                                subtype = VSLENGTH;
                                        } else {
                                                static char cbuf[2];
-                                               pungetc();
-                                               cbuf[0] = c;
+
+                                               pungetc();   /* would like 2 */
+                                               cbuf[0] = c; /* so ... */
                                                cbuf[1] = '\0';
                                                pushstring(cbuf, 1, NULL);
-                                               c = '#';
-                                               subtype = 0;
+                                               c = '#';     /* ${#:...} */
+                                               subtype = 0; /* .. or similar */
                                        }
                                } else {
                                        pungetc();