1# $NetBSD: cond-cmp-unary.mk,v 1.1 2020/09/14 06:22:59 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.if ${:U} 29. error 30.endif 31 32# A variable expression that is not surrounded by quotes is interpreted 33# as a number if possible, otherwise as a string. 34.if ${:U0} 35. error 36.endif 37 38# A non-zero number from a variable expression evaluates to true. 39.if !${:U12345} 40. error 41.endif 42 43all: # nothing 44