Module Name: src
Committed By: rillig
Date: Thu Dec 10 16:47:42 UTC 2020
Modified Files:
src/usr.bin/make/unit-tests: varmod-ifelse.mk
Log Message:
make(1): document limitations of deferred '$' in ':?' modifier
To generate a diff of this commit:
cvs rdiff -u -r1.7 -r1.8 src/usr.bin/make/unit-tests/varmod-ifelse.mk
Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.
Modified files:
Index: src/usr.bin/make/unit-tests/varmod-ifelse.mk
diff -u src/usr.bin/make/unit-tests/varmod-ifelse.mk:1.7 src/usr.bin/make/unit-tests/varmod-ifelse.mk:1.8
--- src/usr.bin/make/unit-tests/varmod-ifelse.mk:1.7 Thu Dec 10 16:36:47 2020
+++ src/usr.bin/make/unit-tests/varmod-ifelse.mk Thu Dec 10 16:47:42 2020
@@ -1,4 +1,4 @@
-# $NetBSD: varmod-ifelse.mk,v 1.7 2020/12/10 16:36:47 rillig Exp $
+# $NetBSD: varmod-ifelse.mk,v 1.8 2020/12/10 16:47:42 rillig Exp $
#
# Tests for the ${cond:?then:else} variable modifier, which evaluates either
# the then-expression or the else-expression, depending on the condition.
@@ -99,6 +99,11 @@ COND:= ${${UNDEF} == "":?bad-assign:bad-
# the '$' of the intended '${VAR}' escapes from the parser in form of the
# expression ${:U\$}. Because of this escaping, the variable "name" and thus
# the condition ends up as "${VAR} == value", just as intended.
+#
+# This hack does not work for variables from .for loops since these are
+# expanded at parse time to their corresponding ${:Uvalue} expressions.
+# Making the '$' of the '${VAR}' expression indirect hides this expression
+# from the parser of the .for loop body. See SubstVarLong.
.MAKEFLAGS: -dc
VAR= value
.if ${ ${:U\$}{VAR} == value :?ok:bad} != "ok"
