1# $NetBSD: varmod-loop-varname.mk,v 1.2 2021/04/04 13:35:26 rillig Exp $ 2# 3# Tests for the first part of the variable modifier ':@var@...@', which 4# contains the variable name to use during the loop. 5 6.MAKE.SAVE_DOLLARS= yes 7 8 9# Before 2021-04-04, the name of the loop variable could be generated 10# dynamically. There was no practical use-case for this. 11# Since var.c 1.907 from 2021-04-04, a '$' is no longer allowed in the 12# variable name. 13.if ${:Uone two three:@${:Ubar:S,b,v,}@+${var}+@} != "+one+ +two+ +three+" 14. error 15.endif 16 17 18# ":::" is a very creative variable name, unlikely to occur in practice. 19# The expression ${\:\:\:} would not work since backslashes can only 20# be escaped in the modifiers, but not in the variable name, therefore 21# the extra indirection via the modifier ':U'. 22.if ${:U1 2 3:@:::@x${${:U\:\:\:}}y@} != "x1y x2y x3y" 23. error 24.endif 25 26 27# "@@" is another creative variable name. 28.if ${:U1 2 3:@\@\@@x${@@}y@} != "x1y x2y x3y" 29. error 30.endif 31 32 33# In extreme cases, even the backslash can be used as variable name. 34# It needs to be doubled though. 35.if ${:U1 2 3:@\\@x${${:Ux:S,x,\\,}}y@} != "x1y x2y x3y" 36. error 37.endif 38 39 40# The variable name can technically be empty, and in this situation 41# the variable value cannot be accessed since the empty "variable" 42# is protected to always return an empty string. 43.if ${:U1 2 3:@@x${}y@} != "xy xy xy" 44. error 45.endif 46 47 48# The :@ modifier resolves the variables from the replacement text once more 49# than expected. In particular, it resolves _all_ variables from the scope, 50# and not only the loop variable (in this case v). 51SRCS= source 52CFLAGS.source= before 53ALL_CFLAGS:= ${SRCS:@src@${CFLAGS.${src}}@} # note the ':=' 54CFLAGS.source+= after 55.if ${ALL_CFLAGS} != "before" 56. error 57.endif 58 59 60# In the following example, the modifier ':@' expands the '$$' to '$'. This 61# means that when the resulting expression is evaluated, these resulting '$' 62# will be interpreted as starting a subexpression. 63# 64# The d means direct reference, the i means indirect reference. 65RESOLVE= ${RES1} $${RES1} 66RES1= 1d${RES2} 1i$${RES2} 67RES2= 2d${RES3} 2i$${RES3} 68RES3= 3 69 70.if ${RESOLVE:@v@w${v}w@} != "w1d2d3w w2i3w w1i2d3 2i\${RES3}w w1d2d3 2i\${RES3} 1i\${RES2}w" 71. error 72.endif 73 74 75# Until 2020-07-20, the variable name of the :@ modifier could end with one 76# or two dollar signs, which were silently ignored. 77# There's no point in allowing a dollar sign in that position. 78# Since var.c 1.907 from 2021-04-04, a '$' is no longer allowed in the 79# variable name. 80.if ${1 2 3:L:@v$@($v)@} != "(1) (2) (3)" 81. error 82.else 83. error 84.endif 85.if ${1 2 3:L:@v$$@($v)@} != "() () ()" 86. error 87.else 88. error 89.endif 90.if ${1 2 3:L:@v$$$@($v)@} != "() () ()" 91. error 92.else 93. error 94.endif 95 96 97# It may happen that there are nested :@ modifiers that use the same name for 98# for the loop variable. These modifiers influence each other. 99# 100# As of 2020-10-18, the :@ modifier is implemented by actually setting a 101# variable in the scope of the expression and deleting it again after the 102# loop. This is different from the .for loops, which substitute the variable 103# expression with ${:Uvalue}, leading to different unwanted side effects. 104# 105# To make the behavior more predictable, the :@ modifier should restore the 106# loop variable to the value it had before the loop. This would result in 107# the string "1a b c1 2a b c2 3a b c3", making the two loops independent. 108.if ${:U1 2 3:@i@$i${:Ua b c:@i@$i@}${i:Uu}@} != "1a b cu 2a b cu 3a b cu" 109. error 110.endif 111 112# During the loop, the variable is actually defined and nonempty. 113# If the loop were implemented in the same way as the .for loop, the variable 114# would be neither defined nor nonempty since all expressions of the form 115# ${var} would have been replaced with ${:Uword} before evaluating them. 116.if defined(var) 117. error 118.endif 119.if ${:Uword:@var@${defined(var):?def:undef} ${empty(var):?empty:nonempty}@} \ 120 != "def nonempty" 121. error 122.endif 123.if defined(var) 124. error 125.endif 126 127all: .PHONY 128