1# $NetBSD: cond-cmp-unary.mk,v 1.3 2022/09/08 05:43:20 rillig Exp $
2#
3# Tests for unary comparisons in .if conditions, that is, comparisons with
4# a single operand.  If the operand is a number, it is compared to zero,
5# if it is a string, it is tested for emptiness.
6
7# The number 0 in all its various representations evaluates to false.
8.if 0 || 0.0 || 0e0 || 0.0e0 || 0.0e10
9.  error
10.endif
11
12# Any other number evaluates to true.
13.if !12345
14.  error
15.endif
16
17# The empty string evaluates to false.
18.if ""
19.  error
20.endif
21
22# Any other string evaluates to true.
23.if !"0"
24.  error
25.endif
26
27# The empty string may come from a variable expression.
28#
29# XXX: As of 2020-11-11, this empty string is interpreted "as a number" in
30# EvalNotEmpty, which is plain wrong.  The bug is in TryParseNumber.
31.if ${:U}
32.  error
33.endif
34
35# A variable expression that is not surrounded by quotes is interpreted
36# as a number if possible, otherwise as a string.
37.if ${:U0}
38.  error
39.endif
40
41# A non-zero number from a variable expression evaluates to true.
42.if !${:U12345}
43.  error
44.endif
45
46# A string of whitespace should evaluate to false.
47#
48# XXX: As of 2020-11-11, the implementation in EvalNotEmpty does not skip
49# whitespace before testing for the end.  This was probably an oversight in
50# a commit from 1992-04-15 saying "A variable is empty when it just contains
51# spaces".
52.if ${:U   }
53.  info This is only reached because of a bug in EvalNotEmpty.
54.else
55.  error
56.endif
57
58# The condition '${VAR:M*}' is almost equivalent to '${VAR:M*} != ""'.  The
59# only case where they differ is for a single word whose numeric value is zero.
60.if ${:U0:M*}
61.  error
62.endif
63.if ${:U0:M*} == ""
64.  error
65.endif
66# Multiple words cannot be parsed as a single number, thus evaluating to true.
67.if !${:U0 0:M*}
68.  error
69.endif
70.if ${:U0 0:M*} == ""
71.  error
72.endif
73
74all: # nothing
75