1# $NetBSD: var-op-append.mk,v 1.12 2023/11/02 05:46:26 rillig Exp $
2#
3# Tests for the '+=' variable assignment operator, which appends to a
4# variable, creating it if necessary.
5#
6# See also
7#	var-op.mk
8#
9# Standards
10#	The '+=' variable assignment operator is planned to be added in
11#	POSIX.1-202x.
12#
13#	This implementation does not support the immediate-expansion macros
14#	specified in POSIX.1-202x.  All variables are delayed-expansion.
15#
16# History
17#	The '+=' variable assignment operator was added before 1993-03-21.
18
19# Appending to an undefined variable is possible.
20# The variable is created, and no extra space is added before the value.
21VAR+=	one
22.if ${VAR} != "one"
23.  error
24.endif
25
26# Appending to an existing variable adds a single space and the value.
27VAR+=	two
28.if ${VAR} != "one two"
29.  error
30.endif
31
32# Appending an empty string nevertheless adds a single space.
33VAR+=	# empty
34.if ${VAR} != "one two "
35.  error
36.endif
37
38# Variable names may contain '+', and this character is also part of the
39# '+=' assignment operator.  As far as possible, the '+' is interpreted as
40# part of the assignment operator.
41#
42# See Parse_Var, AdjustVarassignOp.
43C++=	value
44.if ${C+} != "value" || defined(C++)
45.  error
46.endif
47
48# Before var.c 1.793 from 2021-02-03, the variable name of a newly created
49# variable was expanded two times in a row, which was unexpected but
50# irrelevant in practice since variable names containing dollars lead to
51# strange side effects in several other places as well.
52.MAKEFLAGS: -dv
53VAR.${:U\$\$\$\$\$\$\$\$}+=	dollars
54.MAKEFLAGS: -d0
55.if ${VAR.${:U\$\$\$\$\$\$\$\$}} != "dollars"
56.  error
57.endif
58
59
60# Appending to an environment variable in the global scope creates a global
61# variable of the same name, taking its initial value from the environment
62# variable.  After the assignment, the environment variable is left as-is,
63# the value of the global variable is not synced back to the environment
64# variable.
65export ENV_PLUS_GLOBAL=from-env-value
66ENV_PLUS_GLOBAL+=	appended-value
67.if ${ENV_PLUS_GLOBAL} != "from-env-value appended-value"
68.  error
69.endif
70EXPORTED!=	echo "$$ENV_PLUS_GLOBAL"
71.if ${EXPORTED} != "from-env-value"
72.  error
73.endif
74
75# Appending to an environment variable in the command line scope ignores the
76# environment variable.
77export ENV_PLUS_COMMAND=from-env-value
78.MAKEFLAGS: ENV_PLUS_COMMAND+=appended-command
79.if ${ENV_PLUS_COMMAND} != "appended-command"
80.  error ${ENV_PLUS_COMMAND}
81.endif
82EXPORTED!=	echo "$$ENV_PLUS_GLOBAL"
83.if ${EXPORTED} != "from-env-value"
84.  error
85.endif
86
87
88all:
89