varmod-loop.mk revision 1.3
1 1.3 rillig # $NetBSD: varmod-loop.mk,v 1.3 2020/09/13 07:32:32 rillig Exp $ 2 1.1 rillig # 3 1.2 rillig # Tests for the :@var (a] ...${var}...@ variable modifier. 4 1.1 rillig 5 1.2 rillig all: mod-loop-varname 6 1.2 rillig all: mod-loop-resolve 7 1.2 rillig all: mod-loop-varname-dollar 8 1.2 rillig all: mod-loop-dollar 9 1.1 rillig 10 1.2 rillig # In the :@ modifier, the name of the loop variable can even be generated 11 1.2 rillig # dynamically. There's no practical use-case for this, and hopefully nobody 12 1.2 rillig # will ever depend on this, but technically it's possible. 13 1.2 rillig # Therefore, in -dL mode, this is forbidden, see lint.mk. 14 1.2 rillig mod-loop-varname: 15 1.2 rillig @echo :${:Uone two three:@${:Ubar:S,b,v,}@+${var}+@:Q}: 16 1.2 rillig # ":::" is a very creative variable name, unlikely in practice 17 1.2 rillig # The expression ${\:\:\:} would not work since backslashes can only 18 1.2 rillig # be escaped in the modifiers, but not in the variable name. 19 1.2 rillig @echo :${:U1 2 3:@:::@x${${:U\:\:\:}}y@}: 20 1.2 rillig # "@@" is another creative variable name. 21 1.2 rillig @echo :${:U1 2 3:@\@\@@x${@@}y@}: 22 1.2 rillig # Even "@" works as a variable name since the variable is installed 23 1.2 rillig # in the "current" scope, which in this case is the one from the 24 1.2 rillig # target. 25 1.2 rillig @echo :$@: :${:U1 2 3:@\@@x${@}y@}: :$@: 26 1.2 rillig # In extreme cases, even the backslash can be used as variable name. 27 1.2 rillig # It needs to be doubled though. 28 1.2 rillig @echo :${:U1 2 3:@\\@x${${:Ux:S,x,\\,}}y@}: 29 1.2 rillig 30 1.3 rillig # The variable name can technically be empty, and in this situation 31 1.3 rillig # the variable value cannot be accessed since the empty variable is 32 1.3 rillig # protected to always return an empty string. 33 1.3 rillig @echo empty: :${:U1 2 3:@@x${}y@}: 34 1.3 rillig 35 1.2 rillig # The :@ modifier resolves the variables a little more often than expected. 36 1.2 rillig # In particular, it resolves _all_ variables from the context, and not only 37 1.2 rillig # the loop variable (in this case v). 38 1.2 rillig # 39 1.2 rillig # The d means direct reference, the i means indirect reference. 40 1.2 rillig RESOLVE= ${RES1} $${RES1} 41 1.2 rillig RES1= 1d${RES2} 1i$${RES2} 42 1.2 rillig RES2= 2d${RES3} 2i$${RES3} 43 1.2 rillig RES3= 3 44 1.2 rillig 45 1.2 rillig mod-loop-resolve: 46 1.2 rillig @echo $@:${RESOLVE:@v@w${v}w@:Q}: 47 1.2 rillig 48 1.2 rillig # Until 2020-07-20, the variable name of the :@ modifier could end with one 49 1.2 rillig # or two dollar signs, which were silently ignored. 50 1.2 rillig # There's no point in allowing a dollar sign in that position. 51 1.2 rillig mod-loop-varname-dollar: 52 1.2 rillig @echo $@:${1 2 3:L:@v$@($v)@:Q}. 53 1.2 rillig @echo $@:${1 2 3:L:@v$$@($v)@:Q}. 54 1.2 rillig @echo $@:${1 2 3:L:@v$$$@($v)@:Q}. 55 1.2 rillig 56 1.2 rillig # Demonstrate that it is possible to generate dollar characters using the 57 1.2 rillig # :@ modifier. 58 1.2 rillig # 59 1.2 rillig # These are edge cases that could have resulted in a parse error as well 60 1.2 rillig # since the $@ at the end could have been interpreted as a variable, which 61 1.2 rillig # would mean a missing closing @ delimiter. 62 1.2 rillig mod-loop-dollar: 63 1.2 rillig @echo $@:${:U1:@word@${word}$@:Q}: 64 1.2 rillig @echo $@:${:U2:@word@$${word}$$@:Q}: 65 1.2 rillig @echo $@:${:U3:@word@$$${word}$$$@:Q}: 66 1.2 rillig @echo $@:${:U4:@word@$$$${word}$$$$@:Q}: 67 1.2 rillig @echo $@:${:U5:@word@$$$$${word}$$$$$@:Q}: 68 1.2 rillig @echo $@:${:U6:@word@$$$$$${word}$$$$$$@:Q}: 69
Indexes created Tue Oct 28 12:10:06 GMT 2025