modmisc.mk revision 1.18 1 # $Id: modmisc.mk,v 1.18 2020/07/20 19:03:25 rillig Exp $
2 #
3 # miscellaneous modifier tests
4
5 # do not put any dirs in this list which exist on some
6 # but not all target systems - an exists() check is below.
7 path=:/bin:/tmp::/:.:/no/such/dir:.
8 # strip cwd from path.
9 MOD_NODOT=S/:/ /g:N.:ts:
10 # and decorate, note that $'s need to be doubled. Also note that
11 # the modifier_variable can be used with other modifiers.
12 MOD_NODOTX=S/:/ /g:N.:@d@'$$d'@
13 # another mod - pretend it is more interesting
14 MOD_HOMES=S,/home/,/homes/,
15 MOD_OPT=@d@$${exists($$d):?$$d:$${d:S,/usr,/opt,}}@
16 MOD_SEP=S,:, ,g
17
18 all: modvar modvarloop modsysv mod-HTE emptyvar undefvar
19 all: mod-S mod-C mod-at-varname mod-at-resolve mod-at-dollar
20 all: mod-subst-dollar mod-loop-dollar
21 all: mod-C-limits
22 all: mod-assign
23 all: mod-assign-nested
24 all: mod-tu-space
25
26 modsysv:
27 @echo "The answer is ${libfoo.a:L:libfoo.a=42}"
28
29 modvar:
30 @echo "path='${path}'"
31 @echo "path='${path:${MOD_NODOT}}'"
32 @echo "path='${path:S,home,homes,:${MOD_NODOT}}'"
33 @echo "path=${path:${MOD_NODOTX}:ts:}"
34 @echo "path=${path:${MOD_HOMES}:${MOD_NODOTX}:ts:}"
35
36 .for d in ${path:${MOD_SEP}:N.} /usr/xbin
37 path_$d?= ${d:${MOD_OPT}:${MOD_HOMES}}/
38 paths+= ${d:${MOD_OPT}:${MOD_HOMES}}
39 .endfor
40
41 modvarloop:
42 @echo "path_/usr/xbin=${path_/usr/xbin}"
43 @echo "paths=${paths}"
44 @echo "PATHS=${paths:tu}"
45
46 PATHNAMES= a/b/c def a.b.c a.b/c a a.a .gitignore a a.a
47 mod-HTE:
48 @echo "dirname of '"${PATHNAMES:Q}"' is '"${PATHNAMES:H:Q}"'"
49 @echo "basename of '"${PATHNAMES:Q}"' is '"${PATHNAMES:T:Q}"'"
50 @echo "suffix of '"${PATHNAMES:Q}"' is '"${PATHNAMES:E:Q}"'"
51 @echo "root of '"${PATHNAMES:Q}"' is '"${PATHNAMES:R:Q}"'"
52
53 # When a modifier is applied to the "" variable, the result is discarded.
54 emptyvar:
55 @echo S:${:S,^$,empty,}
56 @echo C:${:C,^$,empty,}
57 @echo @:${:@var@${var}@}
58
59 # The :U modifier turns even the "" variable into something that has a value.
60 # The resulting variable is empty, but is still considered to contain a
61 # single empty word. This word can be accessed by the :S and :C modifiers,
62 # but not by the :@ modifier since it explicitly skips empty words.
63 undefvar:
64 @echo S:${:U:S,^$,empty,}
65 @echo C:${:U:C,^$,empty,}
66 @echo @:${:U:@var@empty@}
67
68 mod-S:
69 @echo :${:Ua b b c:S,a b,,:Q}:
70 @echo :${:Ua b b c:S,a b,,1:Q}:
71 @echo :${:Ua b b c:S,a b,,W:Q}:
72 @echo :${:Ua b b c:S,b,,g:Q}:
73 @echo :${:U1 2 3 1 2 3:S,1 2,___,Wg:S,_,x,:Q}:
74
75 mod-C:
76 @echo :${:Ua b b c:C,a b,,:Q}:
77 @echo :${:Ua b b c:C,a b,,1:Q}:
78 @echo :${:Ua b b c:C,a b,,W:Q}:
79 @echo :${:Uword1 word2:C,****,____,g:C,word,____,:Q}:
80 @echo :${:Ua b b c:C,b,,g:Q}:
81 @echo :${:U1 2 3 1 2 3:C,1 2,___,Wg:C,_,x,:Q}:
82
83 # In the :@ modifier, the name of the loop variable can even be generated
84 # dynamically. There's no practical use-case for this, and hopefully nobody
85 # will ever depend on this, but technically it's possible.
86 mod-at-varname:
87 @echo :${:Uone two three:@${:Ubar:S,b,v,}@+${var}+@:Q}:
88
89 # The :@ modifier resolves the variables a little more often than expected.
90 # In particular, it resolves _all_ variables from the context, and not only
91 # the loop variable (in this case v).
92 #
93 # The d means direct reference, the i means indirect reference.
94 RESOLVE= ${RES1} $${RES1}
95 RES1= 1d${RES2} 1i$${RES2}
96 RES2= 2d${RES3} 2i$${RES3}
97 RES3= 3
98
99 mod-at-resolve:
100 @echo $@:${RESOLVE:@v@w${v}w@:Q}:
101
102 # As of 2020-07-19, the variable name of the :@ modifier may end with one
103 # or two dollar signs, which are silently ignored. There's no point in
104 # allowing a dollar sign in that position.
105 mod-at-dollar:
106 @echo $@:${1 2 3:L:@v$@($v)@:Q}.
107 @echo $@:${1 2 3:L:@v$$@($v)@:Q}.
108 @echo $@:${1 2 3:L:@v$$$@($v)@:Q}.
109
110 # No matter how many dollar characters there are, they all get merged
111 # into a single dollar by the :S modifier.
112 mod-subst-dollar:
113 @echo $@:${:U1:S,^,$,:Q}:
114 @echo $@:${:U2:S,^,$$,:Q}:
115 @echo $@:${:U3:S,^,$$$,:Q}:
116 @echo $@:${:U4:S,^,$$$$,:Q}:
117 @echo $@:${:U5:S,^,$$$$$,:Q}:
118 @echo $@:${:U6:S,^,$$$$$$,:Q}:
119 @echo $@:${:U7:S,^,$$$$$$$,:Q}:
120 @echo $@:${:U8:S,^,$$$$$$$$,:Q}:
121 # This generates no dollar at all:
122 @echo $@:${:UU8:S,^,${:U$$$$$$$$},:Q}:
123 # Here is an alternative way to generate dollar characters.
124 # It's unexpectedly complicated though.
125 @echo $@:${:U:range=5:ts\x24:C,[0-9],,g:Q}:
126
127 # Demonstrate that it is possible to generate dollar characters using the
128 # :@ modifier.
129 #
130 # These are edge cases that could have resulted in a parse error as well
131 # since the $@ at the end could have been interpreted as a variable, which
132 # would mean a missing closing @ delimiter.
133 mod-loop-dollar:
134 @echo $@:${:U1:@word@${word}$@:Q}:
135 @echo $@:${:U2:@word@$${word}$$@:Q}:
136 @echo $@:${:U3:@word@$$${word}$$$@:Q}:
137 @echo $@:${:U4:@word@$$$${word}$$$$@:Q}:
138 @echo $@:${:U5:@word@$$$$${word}$$$$$@:Q}:
139 @echo $@:${:U6:@word@$$$$$${word}$$$$$$@:Q}:
140
141 mod-C-limits:
142 @echo $@:00-ok:${:U1 23 456:C,..,\0\0,:Q}
143 @echo $@:11-missing:${:U1 23 456:C,..,\1\1,:Q}
144 @echo $@:11-ok:${:U1 23 456:C,(.).,\1\1,:Q}
145 @echo $@:22-missing:${:U1 23 456:C,..,\2\2,:Q}
146 @echo $@:22-missing:${:U1 23 456:C,(.).,\2\2,:Q}
147 @echo $@:22-ok:${:U1 23 456:C,(.)(.),\2\2,:Q}
148 # The :C modifier only handles single-digit capturing groups,
149 # which is more than enough for daily use.
150 @echo $@:capture:${:UabcdefghijABCDEFGHIJrest:C,(.)(.)(.)(.)(.)(.)(.)(.)(.)(.)(.)(.)(.)(.)(.)(.)(.)(.)(.)(.),\9\8\7\6\5\4\3\2\1\0\10\11\12,}
151
152 # Just a bit of basic code coverage for the obscure ::= assignment modifiers.
153 mod-assign:
154 @echo $@: ${1 2 3:L:@i@${FIRST::?=$i}@} first=${FIRST}.
155 @echo $@: ${1 2 3:L:@i@${LAST::=$i}@} last=${LAST}.
156 @echo $@: ${1 2 3:L:@i@${APPENDED::+=$i}@} appended=${APPENDED}.
157 @echo $@: ${echo.1 echo.2 echo.3:L:@i@${RAN::!=${i:C,.*,&; & 1>\&2,:S,., ,g}}@} ran:${RAN}.
158 # The assignments happen in the global scope and thus are
159 # preserved even after the shell command has been run.
160 @echo $@: global: ${FIRST:Q}, ${LAST:Q}, ${APPENDED:Q}, ${RAN:Q}.
161
162 mod-assign-nested:
163 @echo $@: ${1:?${THEN1::=then1${IT1::=t1}}:${ELSE1::=else1${IE1::=e1}}}${THEN1}${ELSE1}${IT1}${IE1}
164 @echo $@: ${0:?${THEN2::=then2${IT2::=t2}}:${ELSE2::=else2${IE2::=e2}}}${THEN2}${ELSE2}${IT2}${IE2}
165 @echo $@: ${SINK3:Q}
166 @echo $@: ${SINK4:Q}
167 SINK3:= ${1:?${THEN3::=then3${IT3::=t3}}:${ELSE3::=else3${IE3::=e3}}}${THEN3}${ELSE3}${IT3}${IE3}
168 SINK4:= ${0:?${THEN4::=then4${IT4::=t4}}:${ELSE4::=else4${IE4::=e4}}}${THEN4}${ELSE4}${IT4}${IE4}
169
170 mod-tu-space:
171 # The :tu and :tl modifiers operate on the variable value
172 # as a single string, not as a list of words. Therefore,
173 # the adjacent spaces are preserved.
174 @echo $@: ${a b:L:tu:Q}
175