[src/trunk]: src/usr.bin/make/unit-tests make(1): extend test for modifier pa...

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

details:   https://anonhg.NetBSD.org/src/rev/17de05f9a9de
branches:  trunk
changeset: 958181:17de05f9a9de
user:      rillig <rillig%NetBSD.org@localhost>
date:      Mon Dec 28 00:19:41 2020 +0000

description:
make(1): extend test for modifier parts in ':=' assignments

diffstat:

 usr.bin/make/unit-tests/var-op-expand.mk |  26 ++++++++++++++++++--------
 1 files changed, 18 insertions(+), 8 deletions(-)

diffs (49 lines):

diff -r cd8a57e7a96f -r 17de05f9a9de usr.bin/make/unit-tests/var-op-expand.mk
--- a/usr.bin/make/unit-tests/var-op-expand.mk  Mon Dec 28 00:14:18 2020 +0000
+++ b/usr.bin/make/unit-tests/var-op-expand.mk  Mon Dec 28 00:19:41 2020 +0000
@@ -1,4 +1,4 @@
-# $NetBSD: var-op-expand.mk,v 1.9 2020/12/27 23:25:33 rillig Exp $
+# $NetBSD: var-op-expand.mk,v 1.10 2020/12/28 00:19:41 rillig Exp $
 #
 # Tests for the := variable assignment operator, which expands its
 # right-hand side.
@@ -118,22 +118,32 @@
 
 # In variable assignments using the ':=' operator, there may be expressions
 # containing variable modifiers, and these modifiers may refer to other
-# variables.
+# variables.  These referred-to variables are expanded at the time of
+# assignment.  The undefined variables are kept as-is and are later expanded
+# when evaluating the condition.
 #
 # Contrary to the assignment operator '=', the assignment operator ':='
 # consumes the '$' from modifier parts.
 REF.word=      1:$$ 2:$$$$ 4:$$$$$$$$
-VAR:=          ${:Uword:@word@${REF.${word}}@}, direct: ${REF.word}
-.if ${VAR} != "1:2:\$ 4:\$\$, direct: 1:\$ 2:\$\$ 4:\$\$\$\$"
+.undef REF.undef
+VAR:=          ${:Uword undef:@word@${REF.${word}}@}, direct: ${REF.word} ${REF.undef}
+REF.word=      word.after
+REF.undef=     undef.after
+.if ${VAR} != "1:2:\$ 4:\$\$ undef.after, direct: 1:\$ 2:\$\$ 4:\$\$\$\$ undef.after"
 .  error
 .endif
 
-
 # Just for comparison, the previous example using the assignment operator '='
-# instead of ':='.
+# instead of ':='.  The right-hand side of the assignment is not evaluated at
+# the time of assignment but only later, when ${VAR} appears in the condition.
+#
+# At that point, both REF.word and REF.undef are defined.
 REF.word=      1:$$ 2:$$$$ 4:$$$$$$$$
-VAR=           ${:Uword:@word@${REF.${word}}@}, direct: ${REF.word}
-.if ${VAR} != "1:\$ 2:\$\$ 4:\$\$\$\$, direct: 1:\$ 2:\$\$ 4:\$\$\$\$"
+.undef REF.undef
+VAR=           ${:Uword undef:@word@${REF.${word}}@}, direct: ${REF.word} ${REF.undef}
+REF.word=      word.after
+REF.undef=     undef.after
+.if ${VAR} != "word.after undef.after, direct: word.after undef.after"
 .  error
 .endif