Module Name: src
Committed By: rillig
Date: Sun Dec 27 20:45:52 UTC 2020
Modified Files:
src/usr.bin/make/unit-tests: var-op-expand.mk
Log Message:
make(1): add tests for variable assignments using the ':=' operator
To generate a diff of this commit:
cvs rdiff -u -r1.4 -r1.5 src/usr.bin/make/unit-tests/var-op-expand.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/var-op-expand.mk
diff -u src/usr.bin/make/unit-tests/var-op-expand.mk:1.4 src/usr.bin/make/unit-tests/var-op-expand.mk:1.5
--- src/usr.bin/make/unit-tests/var-op-expand.mk:1.4 Sun Nov 8 14:00:52 2020
+++ src/usr.bin/make/unit-tests/var-op-expand.mk Sun Dec 27 20:45:52 2020
@@ -1,9 +1,90 @@
-# $NetBSD: var-op-expand.mk,v 1.4 2020/11/08 14:00:52 rillig Exp $
+# $NetBSD: var-op-expand.mk,v 1.5 2020/12/27 20:45:52 rillig Exp $
#
# Tests for the := variable assignment operator, which expands its
# right-hand side.
-# TODO: Implementation
+
+# If the right-hand side does not contain a dollar sign, the ':=' assignment
+# operator has the same effect as the '=' assignment operator.
+VAR:= value
+.if ${VAR} != "value"
+. error
+.endif
+
+# When a ':=' assignment is performed, its right-hand side is evaluated and
+# expanded as far as possible. Contrary to other situations, '$$' and
+# variable expressions based on undefined variables are preserved though.
+#
+# Whether a variable expression is undefined or not is determined at the end
+# of evaluating the expression. The consequence is that ${:Ufallback} expands
+# to "fallback"; initially this expression is undefined since it is based on
+# the variable named "", which is guaranteed to be never defined, but at the
+# end of evaluating the expression ${:Ufallback}, the modifier ':U' has turned
+# the expression into a defined expression.
+
+
+# literal dollar signs
+VAR:= $$ $$$$ $$$$$$$$
+.if ${VAR} != "\$ \$\$ \$\$\$\$"
+. error
+.endif
+
+
+# reference to a variable containing a literal dollar sign
+REF= $$ $$$$ $$$$$$$$
+VAR:= ${REF}
+REF= too late
+.if ${VAR} != "\$ \$\$ \$\$\$\$"
+. error
+.endif
+
+
+# reference to an undefined variable
+.undef UNDEF
+VAR:= <${UNDEF}>
+UNDEF= after
+.if ${VAR} != "<after>"
+. error
+.endif
+
+
+# reference to a variable whose name is computed from another variable
+REF2= referred to
+REF= REF2
+VAR:= ${${REF}}
+REF= too late
+.if ${VAR} != "referred to"
+. error
+.endif
+
+
+# expression with an indirect modifier referring to an undefined variable
+.undef UNDEF
+VAR:= ${:${UNDEF}}
+UNDEF= Uwas undefined
+.if ${VAR} != "was undefined"
+. error
+.endif
+
+
+# expression with an indirect modifier referring to another variable that
+# in turn refers to an undefined variable
+#
+# XXX: Even though this is a ':=' assignment, the '${UNDEF}' in the part of
+# the variable modifier is not preserved. To preserve it, ParseModifierPart
+# would have to call VarSubstExpr somehow since this is the only piece of
+# code that takes care of this global variable.
+.undef UNDEF
+REF= U${UNDEF}
+#.MAKEFLAGS: -dv
+VAR:= ${:${REF}}
+#.MAKEFLAGS: -d0
+REF= too late
+UNDEF= Uwas undefined
+.if ${VAR} != ""
+. error
+.endif
+
# XXX: edge case: When a variable name refers to an undefined variable, the
# behavior differs between the '=' and the ':=' assignment operators.
@@ -18,6 +99,7 @@
# preserveUndefined in VarAssign_EvalSubst), in the other expansion it expands
# to an empty string. This way, 2 variables are created using a single
# variable assignment. It's magic. :-/
+.undef UNDEF
.MAKEFLAGS: -dv
VAR_ASSIGN_${UNDEF}= undef value
VAR_SUBST_${UNDEF}:= undef value
