1 # $NetBSD: directive-for.mk,v 1.8 2020/10/25 15:49:03 rillig Exp $
3 # Tests for the .for directive.
5 # Using the .for loop, lists of values can be produced.
6 # In simple cases, the :@var@${var}@ variable modifier can be used to
7 # reach the same effects.
13 .if ${NUMBERS} != "1 2 3"
17 # The .for loop also works for multiple iteration variables.
18 .for name value in VARNAME value NAME2 value2
21 .if ${VARNAME} != "value" || ${NAME2} != "value2"
25 # The .for loop splits the items at whitespace, taking quotes into account,
26 # just like the :M or :S variable modifiers.
28 # Until 2012-06-03, it had split the items exactly at whitespace, without
29 # taking the quotes into account.
32 .for var in one t\ w\ o "three three" 'four four' `five six`
39 # In the body of the .for loop, the iteration variables can be accessed
40 # like normal variables, even though they are not really variables.
42 # Instead, the expression ${var} is transformed into ${:U1}, ${:U2} and so
43 # on, before the loop body is evaluated.
45 # A notable effect of this implementation technique is that the .for
46 # iteration variables and the normal global variables live in separate
47 # namespaces and do not influence each other.
51 .for var var2 in 1 2 3 4
53 .if ${var} != "value before"
54 . warning After the .for loop, var must still have its original value.
56 .if ${var2} != "value before"
57 . warning After the .for loop, var2 must still have its original value.
60 # Everything from the paragraph above also applies if the loop body is
61 # empty, even if there is no actual iteration since the loop items are
66 .for var var2 in ${:U}
68 .if ${var} != "value before"
69 . warning After the .for loop, var must still have its original value.
71 .if ${var2} != "value before"
72 . warning After the .for loop, var2 must still have its original value.
75 # Until 2008-12-21, the values of the iteration variables were simply
76 # inserted as plain text and then parsed as usual, which made it possible
77 # to achieve all kinds of strange effects.
79 # Before that date, the .for loop expanded to:
81 # Since that date, the .for loop expands to:
82 # EXPANSION${:U+}= value
87 EXPANSION${plus}= value
89 .if ${EXPANSION} != "before"
90 . error This must be a make from before 2009.
92 .if ${EXPANSION+} != "value"
93 . error This must be a make from before 2009.
96 # When the outer .for loop is expanded, it sees the expression ${i} and
97 # expands it. The inner loop then has nothing more to expand.
104 # From https://gnats.netbsd.org/29985.
106 # Until 2008-12-21, the .for loop was expanded by replacing the variable
107 # value literally in the body. This could lead to situations where the
108 # characters from the variable value were interpreted as markup rather than
111 # Until 2012-06-03, the .for loop had split the words at whitespace, without
112 # taking quotes into account. This made it possible to have variable values
113 # like "a:\ a:\file.txt" that ended in a single backslash. Since then, the
114 # variable values have been replaced with expressions of the form ${:U...},
115 # which are not interpreted as code anymore.
117 # As of 2020-09-22, a comment in for.c says that it may be possible to
118 # produce an "unwanted substitution", but there is no demonstration code yet.
120 # The above changes prevent a backslash at the end of a word from being
121 # interpreted as part of the code. Because of this, the trailingBackslash
122 # hack in Var_Subst is no longer needed and as of 2020-09-22, has been
124 .for path in a:\ a:\file.txt d:\\ d:\\file.txt
128 # Ensure that braces and parentheses are properly escaped by the .for loop.
129 # Each line must print the same word 3 times.
131 .for v in ( [ { ) ] } (()) [[]] {{}} )( ][ }{
135 # As of 2020-10-25, the variable names may contain arbitrary characters,
136 # except for whitespace. This allows for creative side effects. Hopefully
137 # nobody is misusing this "feature".
139 .for var:Q in value "quoted"
140 . info ${var} ${var:Q} ${var:Q:Q}