1# $NetBSD: cond-token-var.mk,v 1.8 2023/11/19 21:47:52 rillig Exp $
2#
3# Tests for expressions in .if conditions.
4#
5# Note the fine distinction between a variable and an expression.
6# A variable has a name and a value.  To access the value, one writes an
7# expression of the form ${VAR}.  This is a simple
8# expression.  Expressions can get more complicated by adding
9# variable modifiers such as in ${VAR:Mpattern}.
10#
11# XXX: Strictly speaking, variable modifiers should be called expression
12# modifiers instead since they only modify the expression, not the variable.
13# Well, except for the assignment modifiers, these do indeed change the value
14# of the variable.
15
16DEF=	defined
17
18# A defined variable may appear on either side of the comparison.
19.if ${DEF} == ${DEF}
20# expect+1: ok
21.  info ok
22.else
23.  error
24.endif
25
26# A variable that appears on the left-hand side must be defined.
27# expect+1: Malformed conditional (${UNDEF} == ${DEF})
28.if ${UNDEF} == ${DEF}
29.  error
30.endif
31
32# A variable that appears on the right-hand side must be defined.
33# expect+1: Malformed conditional (${DEF} == ${UNDEF})
34.if ${DEF} == ${UNDEF}
35.  error
36.endif
37
38# A defined variable may appear as an expression of its own.
39.if ${DEF}
40.endif
41
42# An undefined variable on its own generates a parse error.
43# expect+1: Malformed conditional (${UNDEF})
44.if ${UNDEF}
45.endif
46
47# The :U modifier turns an undefined expression into a defined expression.
48# Since the expression is defined now, it doesn't generate any parse error.
49.if ${UNDEF:U}
50.endif
51
52# If the value of the expression is a number, it is compared against
53# zero.
54.if ${:U0}
55.  error
56.endif
57.if !${:U1}
58.  error
59.endif
60
61# If the value of the expression is not a number, any non-empty
62# value evaluates to true, even if there is only whitespace.
63.if ${:U}
64.  error
65.endif
66.if !${:U }
67.  error
68.endif
69.if !${:Uanything}
70.  error
71.endif
72