varmod-loop-varname.mk revision 1.12
1 # $NetBSD: varmod-loop-varname.mk,v 1.12 2025/01/11 20:54:46 rillig Exp $ 2 # 3 # Tests for the first part of the variable modifier ':@var (a] ...@', which 4 # contains the variable name to use during the loop. 5 6 # Force the test results to be independent of the default value of this 7 # setting, which is 'yes' for NetBSD's usr.bin/make but 'no' for the bmake 8 # distribution and pkgsrc/devel/bmake. 9 .MAKE.SAVE_DOLLARS= yes 10 11 12 # Before 2021-04-04, the name of the loop variable could be generated 13 # dynamically. There was no practical use-case for this. 14 # Since var.c 1.907 from 2021-04-04, a '$' is no longer allowed in the 15 # variable name. 16 # expect+1: In the :@ modifier, the variable name "${:Ubar:S,b,v,}" must not contain a dollar 17 .if ${:Uone two three:@${:Ubar:S,b,v,}@+${var}+@} != "+one+ +two+ +three+" 18 . error 19 .else 20 . error 21 .endif 22 23 24 # ":::" is a very creative variable name, unlikely to occur in practice. 25 # The expression ${\:\:\:} would not work since backslashes can only 26 # be escaped in the modifiers, but not in the variable name, therefore 27 # the extra indirection via the modifier ':U'. 28 .if ${:U1 2 3:@:::@x${${:U\:\:\:}}y@} != "x1y x2y x3y" 29 . error 30 .endif 31 32 33 # "@@" is another creative variable name. 34 .if ${:U1 2 3:@\@\@@x${@@}y@} != "x1y x2y x3y" 35 . error 36 .endif 37 38 39 # In extreme cases, even the backslash can be used as variable name. 40 # It needs to be doubled though. 41 .if ${:U1 2 3:@\\@x${${:Ux:S,x,\\,}}y@} != "x1y x2y x3y" 42 . error 43 .endif 44 45 46 # The variable name can technically be empty, and in this situation 47 # the variable value cannot be accessed since the empty "variable" 48 # is protected to always return an empty string. 49 .if ${:U1 2 3:@@x${}y@} != "xy xy xy" 50 . error 51 .endif 52 53 54 # The :@ modifier resolves the variables from the replacement text once more 55 # than expected. In particular, it resolves _all_ variables from the scope, 56 # and not only the loop variable (in this case v). 57 SRCS= source 58 CFLAGS.source= before 59 ALL_CFLAGS:= ${SRCS:@src@${CFLAGS.${src}}@} # note the ':=' 60 CFLAGS.source+= after 61 .if ${ALL_CFLAGS} != "before" 62 . error 63 .endif 64 65 66 # In the following example, the modifier ':@' expands the '$$' to '$'. This 67 # means that when the resulting expression is evaluated, these resulting '$' 68 # will be interpreted as starting a subexpression. 69 # 70 # The d means direct reference, the i means indirect reference. 71 RESOLVE= ${RES1} $${RES1} 72 RES1= 1d${RES2} 1i$${RES2} 73 RES2= 2d${RES3} 2i$${RES3} 74 RES3= 3 75 76 .if ${RESOLVE:@v@w${v}w@} != "w1d2d3w w2i3w w1i2d3 2i\${RES3}w w1d2d3 2i\${RES3} 1i\${RES2}w" 77 . error 78 .endif 79 80 81 # Until 2020-07-20, the variable name of the :@ modifier could end with one 82 # or two dollar signs, which were silently ignored. 83 # There's no point in allowing a dollar sign in that position. 84 # Since var.c 1.907 from 2021-04-04, a '$' is no longer allowed in the 85 # variable name. 86 # expect+1: In the :@ modifier, the variable name "v$" must not contain a dollar 87 .if ${1 2 3:L:@v$@($v)@} != "(1) (2) (3)" 88 . error 89 .else 90 . error 91 .endif 92 # expect+1: In the :@ modifier, the variable name "v$$" must not contain a dollar 93 .if ${1 2 3:L:@v$$@($v)@} != "() () ()" 94 . error 95 .else 96 . error 97 .endif 98 # expect+1: In the :@ modifier, the variable name "v$$$" must not contain a dollar 99 .if ${1 2 3:L:@v$$$@($v)@} != "() () ()" 100 . error 101 .else 102 . error 103 .endif 104 105 106 # It may happen that there are nested :@ modifiers that use the same name for 107 # for the loop variable. These modifiers influence each other. 108 # 109 # As of 2020-10-18, the :@ modifier is implemented by actually setting a 110 # variable in the scope of the expression and deleting it again after the 111 # loop. This is different from the .for loops, which substitute the 112 # expression with ${:Uvalue}, leading to different unwanted side effects. 113 # 114 # To make the behavior more predictable, the :@ modifier should restore the 115 # loop variable to the value it had before the loop. This would result in 116 # the string "1a b c1 2a b c2 3a b c3", making the two loops independent. 117 .if ${:U1 2 3:@i@$i${:Ua b c:@i@$i@}${i:Uu}@} != "1a b cu 2a b cu 3a b cu" 118 . error 119 .endif 120 121 # During the loop, the variable is actually defined and nonempty. 122 # If the loop were implemented in the same way as the .for loop, the variable 123 # would be neither defined nor nonempty since all expressions of the form 124 # ${var} would have been replaced with ${:Uword} before evaluating them. 125 .if defined(var) 126 . error 127 .endif 128 .if ${:Uword:@var@${defined(var):?def:undef} ${empty(var):?empty:nonempty}@} \ 129 != "def nonempty" 130 . error 131 .endif 132 .if defined(var) 133 . error 134 .endif 135 136 all: .PHONY 137
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