varmod-loop-varname.mk revision 1.5
1 # $NetBSD: varmod-loop-varname.mk,v 1.5 2023/06/01 20:56:35 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 '$' is no longer allowed in the 15 # variable name. 16 # expect+2: In the :@ modifier of "", the variable name "${:Ubar:S,b,v,}" must not contain a dollar 17 # expect+1: Malformed conditional (${:Uone two three:@${:Ubar:S,b,v,}@+${var}+@} != "+one+ +two+ +three+") 18 .if ${:Uone two three:@${:Ubar:S,b,v,}@+${var}+@} != "+one+ +two+ +three+" 19 . error 20 .else 21 . error 22 .endif 23 24 25 # ":::" is a very creative variable name, unlikely to occur in practice. 26 # The expression ${\:\:\:} would not work since backslashes can only 27 # be escaped in the modifiers, but not in the variable name, therefore 28 # the extra indirection via the modifier ':U'. 29 .if ${:U1 2 3:@:::@x${${:U\:\:\:}}y@} != "x1y x2y x3y" 30 . error 31 .endif 32 33 34 # "@@" is another creative variable name. 35 .if ${:U1 2 3:@\@\@@x${@@}y@} != "x1y x2y x3y" 36 . error 37 .endif 38 39 40 # In extreme cases, even the backslash can be used as variable name. 41 # It needs to be doubled though. 42 .if ${:U1 2 3:@\\@x${${:Ux:S,x,\\,}}y@} != "x1y x2y x3y" 43 . error 44 .endif 45 46 47 # The variable name can technically be empty, and in this situation 48 # the variable value cannot be accessed since the empty "variable" 49 # is protected to always return an empty string. 50 .if ${:U1 2 3:@@x${}y@} != "xy xy xy" 51 . error 52 .endif 53 54 55 # The :@ modifier resolves the variables from the replacement text once more 56 # than expected. In particular, it resolves _all_ variables from the scope, 57 # and not only the loop variable (in this case v). 58 SRCS= source 59 CFLAGS.source= before 60 ALL_CFLAGS:= ${SRCS:@src@${CFLAGS.${src}}@} # note the ':=' 61 CFLAGS.source+= after 62 .if ${ALL_CFLAGS} != "before" 63 . error 64 .endif 65 66 67 # In the following example, the modifier ':@' expands the '$$' to '$'. This 68 # means that when the resulting expression is evaluated, these resulting '$' 69 # will be interpreted as starting a subexpression. 70 # 71 # The d means direct reference, the i means indirect reference. 72 RESOLVE= ${RES1} $${RES1} 73 RES1= 1d${RES2} 1i$${RES2} 74 RES2= 2d${RES3} 2i$${RES3} 75 RES3= 3 76 77 .if ${RESOLVE:@v@w${v}w@} != "w1d2d3w w2i3w w1i2d3 2i\${RES3}w w1d2d3 2i\${RES3} 1i\${RES2}w" 78 . error 79 .endif 80 81 82 # Until 2020-07-20, the variable name of the :@ modifier could end with one 83 # or two dollar signs, which were silently ignored. 84 # There's no point in allowing a dollar sign in that position. 85 # Since var.c 1.907 from 2021-04-04, a '$' is no longer allowed in the 86 # variable name. 87 # expect+2: In the :@ modifier of "1 2 3", the variable name "v$" must not contain a dollar 88 # expect+1: Malformed conditional (${1 2 3:L:@v$@($v)@} != "(1) (2) (3)") 89 .if ${1 2 3:L:@v$@($v)@} != "(1) (2) (3)" 90 . error 91 .else 92 . error 93 .endif 94 # expect+2: In the :@ modifier of "1 2 3", the variable name "v$$" must not contain a dollar 95 # expect+1: Malformed conditional (${1 2 3:L:@v$$@($v)@} != "() () ()") 96 .if ${1 2 3:L:@v$$@($v)@} != "() () ()" 97 . error 98 .else 99 . error 100 .endif 101 # expect+2: In the :@ modifier of "1 2 3", the variable name "v$$$" must not contain a dollar 102 # expect+1: Malformed conditional (${1 2 3:L:@v$$$@($v)@} != "() () ()") 103 .if ${1 2 3:L:@v$$$@($v)@} != "() () ()" 104 . error 105 .else 106 . error 107 .endif 108 109 110 # It may happen that there are nested :@ modifiers that use the same name for 111 # for the loop variable. These modifiers influence each other. 112 # 113 # As of 2020-10-18, the :@ modifier is implemented by actually setting a 114 # variable in the scope of the expression and deleting it again after the 115 # loop. This is different from the .for loops, which substitute the variable 116 # expression with ${:Uvalue}, leading to different unwanted side effects. 117 # 118 # To make the behavior more predictable, the :@ modifier should restore the 119 # loop variable to the value it had before the loop. This would result in 120 # the string "1a b c1 2a b c2 3a b c3", making the two loops independent. 121 .if ${:U1 2 3:@i@$i${:Ua b c:@i@$i@}${i:Uu}@} != "1a b cu 2a b cu 3a b cu" 122 . error 123 .endif 124 125 # During the loop, the variable is actually defined and nonempty. 126 # If the loop were implemented in the same way as the .for loop, the variable 127 # would be neither defined nor nonempty since all expressions of the form 128 # ${var} would have been replaced with ${:Uword} before evaluating them. 129 .if defined(var) 130 . error 131 .endif 132 .if ${:Uword:@var@${defined(var):?def:undef} ${empty(var):?empty:nonempty}@} \ 133 != "def nonempty" 134 . error 135 .endif 136 .if defined(var) 137 . error 138 .endif 139 140 all: .PHONY 141
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