diff options
Diffstat (limited to 'unit-tests/varmod-loop.mk')
| -rw-r--r-- | unit-tests/varmod-loop.mk | 49 |
1 files changed, 47 insertions, 2 deletions
diff --git a/unit-tests/varmod-loop.mk b/unit-tests/varmod-loop.mk index a3fbbfceae8d..654c449d7bfa 100644 --- a/unit-tests/varmod-loop.mk +++ b/unit-tests/varmod-loop.mk @@ -1,7 +1,9 @@ -# $NetBSD: varmod-loop.mk,v 1.5 2020/10/31 12:34:03 rillig Exp $ +# $NetBSD: varmod-loop.mk,v 1.8 2020/11/12 00:40:55 rillig Exp $ # # Tests for the :@var@...${var}...@ variable modifier. +.MAKE.SAVE_DOLLARS= yes + all: mod-loop-varname all: mod-loop-resolve all: mod-loop-varname-dollar @@ -57,7 +59,7 @@ mod-loop-varname-dollar: @echo $@:${1 2 3:L:@v$$@($v)@:Q}. @echo $@:${1 2 3:L:@v$$$@($v)@:Q}. -# Demonstrate that it is possible to generate dollar characters using the +# Demonstrate that it is possible to generate dollar signs using the # :@ modifier. # # These are edge cases that could have resulted in a parse error as well @@ -100,3 +102,46 @@ mod-loop-dollar: .if defined(var) . error .endif + +# Assignment using the ':=' operator, combined with the :@var@ modifier +# +8_DOLLARS= $$$$$$$$ +# This string literal is written with 8 dollars, and this is saved as the +# variable value. But as soon as this value is evaluated, it goes through +# Var_Subst, which replaces each '$$' with a single '$'. This could be +# prevented by VARE_KEEP_DOLLAR, but that flag is usually removed before +# expanding subexpressions. See ApplyModifier_Loop and ParseModifierPart +# for examples. +# +.MAKEFLAGS: -dcp +USE_8_DOLLARS= ${:U1:@var@${8_DOLLARS}@} ${8_DOLLARS} $$$$$$$$ +.if ${USE_8_DOLLARS} != "\$\$\$\$ \$\$\$\$ \$\$\$\$" +. error +.endif +# +SUBST_CONTAINING_LOOP:= ${USE_8_DOLLARS} +# The ':=' assignment operator evaluates the variable value using the flag +# VARE_KEEP_DOLLAR, which means that some dollar signs are preserved, but not +# all. The dollar signs in the top-level expression and in the indirect +# ${8_DOLLARS} are preserved. +# +# The variable modifier :@var@ does not preserve the dollar signs though, no +# matter in which context it is evaluated. What happens in detail is: +# First, the modifier part "${8_DOLLARS}" is parsed without expanding it. +# Next, each word of the value is expanded on its own, and at this moment +# in ApplyModifier_Loop, the VARE_KEEP_DOLLAR flag is not passed down to +# ModifyWords, resulting in "$$$$" for the first word of USE_8_DOLLARS. +# +# The remaining words of USE_8_DOLLARS are not affected by any variable +# modifier and are thus expanded with the flag VARE_KEEP_DOLLAR in action. +# The variable SUBST_CONTAINING_LOOP therefore gets assigned the raw value +# "$$$$ $$$$$$$$ $$$$$$$$". +# +# The variable expression in the condition then expands this raw stored value +# once, resulting in "$$ $$$$ $$$$". The effects from VARE_KEEP_DOLLAR no +# longer take place since they had only been active during the evaluation of +# the variable assignment. +.if ${SUBST_CONTAINING_LOOP} != "\$\$ \$\$\$\$ \$\$\$\$" +. error +.endif +.MAKEFLAGS: -d0 |