1# $NetBSD: cond-cmp-unary.mk,v 1.2 2020/11/11 07:30:11 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 evaluates to false. 8.if 0 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 58all: # nothing 59