[src/trunk]: src/usr.bin/make make: fix documentation for ModChain

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

details:   https://anonhg.NetBSD.org/src/rev/43a97b4bfc08
branches:  trunk
changeset: 953683:43a97b4bfc08
user:      rillig <rillig%NetBSD.org@localhost>
date:      Tue Mar 16 16:21:27 2021 +0000

description:
make: fix documentation for ModChain

The outer ModChain can be interrupted by an inner ModChain, but it
continues to exist.

No functional change.

diffstat:

 usr.bin/make/var.c |  23 ++++++++++++++---------
 1 files changed, 14 insertions(+), 9 deletions(-)

diffs (48 lines):

diff -r 3f2d5366d2e1 -r 43a97b4bfc08 usr.bin/make/var.c
--- a/usr.bin/make/var.c        Tue Mar 16 08:16:53 2021 +0000
+++ b/usr.bin/make/var.c        Tue Mar 16 16:21:27 2021 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: var.c,v 1.891 2021/03/15 20:00:50 rillig Exp $ */
+/*     $NetBSD: var.c,v 1.892 2021/03/16 16:21:27 rillig Exp $ */
 
 /*
  * Copyright (c) 1988, 1989, 1990, 1993
@@ -140,7 +140,7 @@
 #include "metachar.h"
 
 /*     "@(#)var.c      8.3 (Berkeley) 3/19/94" */
-MAKE_RCSID("$NetBSD: var.c,v 1.891 2021/03/15 20:00:50 rillig Exp $");
+MAKE_RCSID("$NetBSD: var.c,v 1.892 2021/03/16 16:21:27 rillig Exp $");
 
 typedef enum VarFlags {
        VFL_NONE        = 0,
@@ -2062,17 +2062,22 @@
  * The status of applying a chain of modifiers to an expression.
  *
  * The modifiers of an expression are broken into chains of modifiers,
- * starting a new chain whenever an indirect modifier starts or ends.
+ * starting a new nested chain whenever an indirect modifier starts.  There
+ * are at most 2 nesting levels: the outer one for the direct modifiers, and
+ * the inner one for the indirect modifiers.
  *
- * For example, the expression ${VAR:M*:${IND1}:${IND2}:O:u} has 4 chains of
+ * For example, the expression ${VAR:M*:${IND1}:${IND2}:O:u} has 3 chains of
  * modifiers:
  *
- *     Chain 1 is ':M*', consisting of the single modifier ':M*'.
- *     Chain 2 is all modifiers from the value of the variable named 'IND1'.
- *     Chain 3 is all modifiers from the value of the variable named 'IND2'.
- *     Chain 4 is ':O:u', consisting of the 2 modifiers ':O' and ':u'.
+ *     Chain 1 starts with the single modifier ':M*'.
+ *       Chain 2 starts with all modifiers from ${IND1}.
+ *       Chain 2 ends at the ':' between ${IND1} and ${IND2}.
+ *       Chain 3 starts with all modifiers from ${IND1}.
+ *       Chain 2 ends at the ':' after ${IND2}.
+ *     Chain 1 continues with the the 2 modifiers ':O' and ':u'.
+ *     Chain 1 ends at the final '}' of the expression.
  *
- * After such a chain has finished, its properties no longer have any effect.
+ * After such a chain ends, its properties no longer have any effect.
  *
  * It may or may not have been intended that 'defined' has scope Expr while
  * 'sep' and 'oneBigWord' have smaller scope.