1# $NetBSD: varmod-assign.mk,v 1.8 2020/10/18 21:37:24 rillig Exp $ 2# 3# Tests for the obscure ::= variable modifiers, which perform variable 4# assignments during evaluation, just like the = operator in C. 5 6all: mod-assign 7all: mod-assign-nested 8all: mod-assign-empty 9all: mod-assign-parse 10all: mod-assign-shell-error 11 12mod-assign: 13 # The ::?= modifier applies the ?= assignment operator 3 times. 14 # The ?= operator only has an effect for the first time, therefore 15 # the variable FIRST ends up with the value 1. 16 @echo $@: ${1 2 3:L:@i@${FIRST::?=$i}@} first=${FIRST}. 17 18 # The ::= modifier applies the = assignment operator 3 times. 19 # The = operator overwrites the previous value, therefore the 20 # variable LAST ends up with the value 3. 21 @echo $@: ${1 2 3:L:@i@${LAST::=$i}@} last=${LAST}. 22 23 # The ::+= modifier applies the += assignment operator 3 times. 24 # The += operator appends 3 times to the variable, therefore 25 # the variable APPENDED ends up with the value "1 2 3". 26 @echo $@: ${1 2 3:L:@i@${APPENDED::+=$i}@} appended=${APPENDED}. 27 28 # The ::!= modifier applies the != assignment operator 3 times. 29 # The side effects of the shell commands are visible in the output. 30 # Just as with the ::= modifier, the last value is stored in the 31 # RAN variable. 32 @echo $@: ${echo.1 echo.2 echo.3:L:@i@${RAN::!=${i:C,.*,&; & 1>\&2,:S,., ,g}}@} ran:${RAN}. 33 34 # The assignments happen in the global scope and thus are 35 # preserved even after the shell command has been run. 36 @echo $@: global: ${FIRST:Q}, ${LAST:Q}, ${APPENDED:Q}, ${RAN:Q}. 37 38mod-assign-nested: 39 # The condition "1" is true, therefore THEN1 gets assigned a value, 40 # and IT1 as well. Nothing surprising here. 41 @echo $@: ${1:?${THEN1::=then1${IT1::=t1}}:${ELSE1::=else1${IE1::=e1}}}${THEN1}${ELSE1}${IT1}${IE1} 42 43 # The condition "0" is false, therefore ELSE1 gets assigned a value, 44 # and IE1 as well. Nothing surprising here as well. 45 @echo $@: ${0:?${THEN2::=then2${IT2::=t2}}:${ELSE2::=else2${IE2::=e2}}}${THEN2}${ELSE2}${IT2}${IE2} 46 47 # The same effects happen when the variables are defined elsewhere. 48 @echo $@: ${SINK3:Q} 49 @echo $@: ${SINK4:Q} 50SINK3:= ${1:?${THEN3::=then3${IT3::=t3}}:${ELSE3::=else3${IE3::=e3}}}${THEN3}${ELSE3}${IT3}${IE3} 51SINK4:= ${0:?${THEN4::=then4${IT4::=t4}}:${ELSE4::=else4${IE4::=e4}}}${THEN4}${ELSE4}${IT4}${IE4} 52 53mod-assign-empty: 54 # Assigning to the empty variable would obviously not work since that 55 # variable is write-protected. Therefore it is rejected early with a 56 # "Bad modifier" message. 57 # 58 # XXX: The error message is hard to read since the variable name is 59 # empty. This leads to a trailing space in the error message. 60 @echo $@: ${::=value} 61 62 # In this variant, it is not as obvious that the name of the 63 # expression is empty. Assigning to it is rejected as well, with the 64 # same "Bad modifier" message. 65 # 66 # XXX: The error message is hard to read since the variable name is 67 # empty. This leads to a trailing space in the error message. 68 @echo $@: ${:Uvalue::=overwritten} 69 70 # The :L modifier sets the value of the expression to its variable 71 # name. The name of the expression is "VAR", therefore assigning to 72 # that variable works. 73 @echo $@: ${VAR:L::=overwritten} VAR=${VAR} 74 75mod-assign-parse: 76 # The modifier for assignment operators starts with a ':'. 77 # An 'x' after that is an invalid modifier. 78 @echo ${ASSIGN::x} # 'x' is an unknown assignment operator 79 80 # When parsing an assignment operator fails because the operator is 81 # incomplete, make falls back to the SysV modifier. 82 @echo ${SYSV::=sysv\:x}${SYSV::x=:y} 83 84 @echo ${ASSIGN::=value # missing closing brace 85 86mod-assign-shell-error: 87 # If the command succeeds, the variable is assigned. 88 @${SH_OK::!= echo word; true } echo ok=${SH_OK} 89 90 # If the command fails, the variable keeps its previous value. 91 # FIXME: the error message says: "previous" returned non-zero status 92 @${SH_ERR::=previous} 93 @${SH_ERR::!= echo word; false } echo err=${SH_ERR} 94 95# XXX: The ::= modifier expands its right-hand side, exactly once. 96# This differs subtly from normal assignments such as '+=' or '=', which copy 97# their right-hand side literally. 98APPEND.prev= previous 99APPEND.var= ${APPEND.prev} 100APPEND.indirect= indirect $${:Unot expanded} 101APPEND.dollar= $${APPEND.indirect} 102.if ${APPEND.var::+=${APPEND.dollar}} != "" 103. error 104.endif 105.if ${APPEND.var} != "previous indirect \${:Unot expanded}" 106. error 107.endif 108