1# $NetBSD: varmod-remember.mk,v 1.9 2023/02/09 22:21:57 rillig Exp $ 2# 3# Tests for the :_ modifier, which saves the current expression value 4# in the _ variable or another, to be used later again. 5 6 7# The ':_' modifier is typically used in situations where the value of an 8# expression is needed at the same time as a sequence of numbers. In these 9# cases, the value of the expression is saved in the temporary variable '_', 10# from where it is taken later in the same expression. 11ABC= ${A B C:L:_:range:@i@$i=${_:[$i]}@} 12DEF= ${D E F:L:_:range:@i@$i=${_:[$i]}@} 13GHI= ${G H I:L:_:range:@i@$i=${_:[$i]}@} 14 15ABC.global:= ${ABC} # is evaluated in the global scope 16.if ${ABC.global} != "1=A 2=B 3=C" 17. error 18.endif 19 20.if ${DEF} != "1=D 2=E 3=F" # is evaluated in the command line scope 21. error 22.endif 23 24# Before var.c 1.1040 from 2023-02-09, the temporary variable '_' was placed 25# in the scope of the current evaluation, which meant that after the first 26# ':_' modifier had been evaluated in command line scope, all further 27# evaluations in global scope could not overwrite the variable '_' anymore, 28# as the command line scope takes precedence over the global scope. 29# The expression ${GHI} therefore evaluated to '1=D 2=E 3=F', reusing the 30# value of '_' from the previous evaluation in command line scope. 31GHI.global:= ${GHI} # is evaluated in the global scope 32.if ${GHI.global} != "1=G 2=H 3=I" 33. error 34.endif 35 36 37# In the parameterized form, having the variable name on the right side of 38# the = assignment operator looks confusing. In almost all other situations, 39# the variable name is on the left-hand side of the = operator, therefore 40# '_=SAVED' looks like it would copy 'SAVED' to '_'. Luckily, this modifier 41# is only rarely needed. 42.if ${1 2 3:L:@var@${var:_=SAVED:}@} != "1 2 3" 43. error 44.elif ${SAVED} != "3" 45. error 46.endif 47 48 49# The ':_' modifier takes a variable name as optional argument. Before var.c 50# 1.867 from 2021-03-14, this variable name could refer to other variables, 51# such as in 'VAR.$p'. It was not possible to refer to 'VAR.${param}' though, 52# as that form caused a parse error. The cause for the parse error in 53# '${...:_=VAR.${param}}' is that the variable name is parsed in an ad-hoc 54# manner, stopping at the first ':', ')' or '}', without taking any nested 55# expressions into account. Due to this inconsistency that short expressions 56# are possible but long expressions aren't, the name of the temporary variable 57# is no longer expanded. 58# 59# TODO: Warn about the unusual variable name '$S'. 60S= INDIRECT_VARNAME 61.if ${value:L:@var@${var:_=$S}@} != "value" 62. error 63.elif defined(INDIRECT_VARNAME) 64. error 65.endif 66 67 68# When a variable using ':_' refers to another variable that also uses ':_', 69# the value of the temporary variable '_' from the inner expression leaks into 70# the evaluation of the outer expression. If the expressions were evaluated 71# independently, the last word of the result would be outer_='outer' instead. 72INNER= ${inner:L:_:@i@$i inner_='$_'@} 73OUTER= ${outer:L:_:@o@$o ${INNER} outer_='$_'@} 74.if ${OUTER} != "outer inner inner_='inner' outer_='inner'" 75.endif 76 77 78all: 79