1# $NetBSD: directive-for.mk,v 1.10 2020/12/27 09:58:35 rillig Exp $ 2# 3# Tests for the .for directive. 4# 5# TODO: Describe naming conventions for the loop variables. 6# .for f in values 7# .for file in values 8# .for _FILE_ in values 9# .for .FILE. in values 10# .for _f_ in values 11 12# Using the .for loop, lists of values can be produced. 13# In simple cases, the :@var@${var}@ variable modifier can be used to 14# reach the same effects. 15# 16.undef NUMBERS 17.for num in 1 2 3 18NUMBERS+= ${num} 19.endfor 20.if ${NUMBERS} != "1 2 3" 21. error 22.endif 23 24# The .for loop also works for multiple iteration variables. 25# This is something that the variable modifier :@ cannot do. 26.for name value in VARNAME value NAME2 value2 27${name}= ${value} 28.endfor 29.if ${VARNAME} != "value" || ${NAME2} != "value2" 30. error 31.endif 32 33# The .for loop splits the items at whitespace, taking quotes into account, 34# just like the :M or :S variable modifiers. 35# 36# Until 2012-06-03, it had split the items exactly at whitespace, without 37# taking the quotes into account. This had resulted in 10 words. 38# 39.undef WORDS 40.for var in one t\ w\ o "three three" 'four four' `five six` 41WORDS+= counted 42.endfor 43.if ${WORDS:[#]} != 6 44. error 45.endif 46 47# In the body of the .for loop, the iteration variables can be accessed 48# like normal variables, even though they are not really variables. 49# 50# Instead, the expression ${var} is transformed into ${:U1}, ${:U2} and so 51# on, before the loop body is evaluated. 52# 53# A notable effect of this implementation technique is that the .for 54# iteration variables and the normal global variables live in separate 55# namespaces and do not influence each other. 56# 57var= value before 58var2= value before 59.for var var2 in 1 2 3 4 60.endfor 61.if ${var} != "value before" 62. warning After the .for loop, var must still have its original value. 63.endif 64.if ${var2} != "value before" 65. warning After the .for loop, var2 must still have its original value. 66.endif 67 68# Everything from the paragraph above also applies if the loop body is 69# empty, even if there is no actual iteration since the loop items are 70# also empty. 71# 72var= value before 73var2= value before 74.for var var2 in ${:U} 75.endfor 76.if ${var} != "value before" 77. warning After the .for loop, var must still have its original value. 78.endif 79.if ${var2} != "value before" 80. warning After the .for loop, var2 must still have its original value. 81.endif 82 83# Until 2008-12-21, the values of the iteration variables were simply 84# inserted as plain text and then parsed as usual, which made it possible 85# to achieve all kinds of strange effects. 86# 87# Before that date, the .for loop expanded to: 88# EXPANSION+= value 89# Since that date, the .for loop expands to: 90# EXPANSION${:U+}= value 91# 92EXPANSION= before 93EXPANSION+ = before 94.for plus in + 95EXPANSION${plus}= value 96.endfor 97.if ${EXPANSION} != "before" 98. error This must be a make from before 2009. 99.endif 100.if ${EXPANSION+} != "value" 101. error This must be a make from before 2009. 102.endif 103 104# When the outer .for loop is expanded, it sees the expression ${i} and 105# expands it. The inner loop then has nothing more to expand. 106.for i in outer 107. for i in inner 108. info ${i} 109. endfor 110.endfor 111 112# From https://gnats.netbsd.org/29985. 113# 114# Until 2008-12-21, the .for loop was expanded by replacing the variable 115# value literally in the body. This could lead to situations where the 116# characters from the variable value were interpreted as markup rather than 117# plain text. 118# 119# Until 2012-06-03, the .for loop had split the words at whitespace, without 120# taking quotes into account. This made it possible to have variable values 121# like "a:\ a:\file.txt" that ended in a single backslash. Since then, the 122# variable values have been replaced with expressions of the form ${:U...}, 123# which are not interpreted as code anymore. 124# 125# As of 2020-09-22, a comment in for.c says that it may be possible to 126# produce an "unwanted substitution", but there is no demonstration code yet. 127# 128# The above changes prevent a backslash at the end of a word from being 129# interpreted as part of the code. Because of this, the trailingBackslash 130# hack in Var_Subst is no longer needed and as of 2020-09-22, has been 131# removed. 132.for path in a:\ a:\file.txt d:\\ d:\\file.txt 133. info ${path} 134.endfor 135 136# Ensure that braces and parentheses are properly escaped by the .for loop. 137# Each line must print the same word 3 times. 138# See GetEscapes. 139.for v in ( [ { ) ] } (()) [[]] {{}} )( ][ }{ 140. info $v ${v} $(v) 141.endfor 142 143# As of 2020-10-25, the variable names may contain arbitrary characters, 144# except for whitespace. This allows for creative side effects. Hopefully 145# nobody is misusing this "feature". 146var= outer 147.for var:Q in value "quoted" 148. info ${var} ${var:Q} ${var:Q:Q} 149.endfor 150 151 152# XXX: A parse error or evaluation error in the items of the .for loop 153# should skip the whole loop. As of 2020-12-27, the loop is expanded twice. 154.for var in word1 ${:Uword2:Z} word3 155. info XXX: Not reached ${var} 156.endfor 157 158all: 159 @:; 160