1 #
2 # Var refs are done with ${!a}
3 #
4 # local/declare -n is tested in spec/named-ref.test.sh.
5 #
6 # http://stackoverflow.com/questions/16461656/bash-how-to-pass-array-as-an-argument-to-a-function
7
8 #### var ref ${!a}
9 a=b
10 b=c
11 echo ref ${!a} ${a}
12 ## stdout: ref c b
13
14 #### ${!ref-default}
15 ref=x
16 echo x=${!ref-default}
17
18 x=''
19 echo x=${!ref-default}
20
21 x=foo
22 echo x=${!ref-default}
23
24 ## STDOUT:
25 x=default
26 x=
27 x=foo
28 ## END
29
30 #### ${!undef:-}
31 # bash gives empty string, but I feel like this could be an error
32 echo undef=${!undef-'default'}
33 echo undef=${!undef}
34
35 set -u
36 echo NOUNSET
37 echo undef=${!undef-'default'}
38 echo undef=${!undef}
39
40 ## status: 1
41 ## STDOUT:
42 undef=default
43 undef=
44 NOUNSET
45 undef=default
46 ## END
47
48 #### comparison to ${!array[@]} keys (similar SYNTAX)
49 shopt --set compat_array # bypass errors on ${!a} and ${!A}
50
51 declare -a a=(x y)
52 argv.py "${!a[@]}"
53 echo a_keys=$?
54
55 argv.py "${!a}" # missing [] is equivalent to ${!a[0]} ?
56 echo a_nobrackets=$?
57
58 echo ---
59 declare -A A=([A]=a [B]=b)
60
61 argv.py ${!A[@]}
62 echo A_keys=$?
63
64 argv.py "${!A}" # missing [] is equivalent to ${!A[0]} ?
65 echo A_nobrackets=$?
66
67 ## STDOUT:
68 ['0', '1']
69 a_keys=0
70 ['']
71 a_nobrackets=0
72 ---
73 ['A', 'B']
74 A_keys=0
75 ['']
76 A_nobrackets=0
77 ## END
78
79 #### ${!a[@]-'default'} is illegal
80
81 # bash disallows this when a is an array. We make it an error because [@]
82 # implies it's an array.
83
84 argv.py "${!a[@]-default}"
85 echo status=$?
86
87 a=(x y z)
88 argv.py "${!a[@]-default}"
89 echo status=$?
90 ## status: 1
91 ## STDOUT:
92 ## END
93 ## BUG bash status: 0
94 ## BUG bash STDOUT:
95 ['default']
96 status=0
97 status=1
98 ## END
99
100
101 #### var ref to $@ with @
102 set -- one two
103 ref='@'
104 echo ref=${!ref}
105 ## STDOUT:
106 ref=one two
107 ## END
108
109 #### var ref to $1 and $2 with 1 and 2
110 set -- one two
111 ref1='1'
112 echo ref1=${!ref1}
113 ref2='2'
114 echo ref2=${!ref2}
115
116 ## STDOUT:
117 ref1=one
118 ref2=two
119 ## END
120
121 #### var ref: 1, @, *
122 set -- x y
123 ref=1; argv.py "${!ref}"
124 ref=@; argv.py "${!ref}"
125 ref=*; argv.py "${!ref}" # maybe_decay_array bug?
126
127 ## STDOUT:
128 ['x']
129 ['x', 'y']
130 ['x y']
131 ## END
132
133 #### var ref to special var BASH_SOURCE
134 ref='LINENO'
135 echo lineno=${!ref}
136 ## STDOUT:
137 lineno=2
138 ## END
139
140 #### var ref to $? with '?'
141 myfunc() {
142 local ref=$1
143 echo ${!ref}
144 }
145 myfunc FUNCNAME
146 myfunc '?'
147 ## STDOUT:
148 myfunc
149 0
150 ## END
151
152
153 #### Var ref, then assignment with ${ := }
154 z=zz
155 zz=
156 echo ${!z:=foo}
157 echo ${!z:=bar}
158 ## STDOUT:
159 foo
160 foo
161 ## END
162
163 #### Var ref, then error with ${ ? }
164 w=ww
165 ww=
166 echo ${!w:?'my message'}
167 echo done
168 ## status: 1
169 ## STDOUT:
170 ## END
171
172 #### Indirect expansion, THEN suffix operators
173 shopt -s compat_array
174
175 check_eq() {
176 [ "$1" = "$2" ] || { echo "$1 vs $2"; }
177 }
178 check_expand() {
179 val=$(eval "echo \"$1\"")
180 [ "$val" = "$2" ] || { echo "$1 -> expected $2, got $val"; }
181 }
182 check_err() {
183 e="$1"
184 msg=$(eval "$e" 2>&1) && echo "bad success: $e"
185 if test -n "$2"; then
186 if [[ "$msg" != $2 ]]; then
187 echo "Expected error: $e"
188 echo "Got error : $msg"
189 fi
190 fi
191 }
192 # Nearly everything in manual section 3.5.3 "Shell Parameter Expansion"
193 # is allowed after a !-indirection.
194 #
195 # Not allowed: any further prefix syntax.
196 x=xx; xx=aaabcc
197 xd=x
198 check_err '${!!xd}'
199 check_err '${!!x*}'
200 a=(asdf x)
201 check_err '${!!a[*]}'
202 check_err '${!#x}'
203 check_err '${!#a[@]}'
204 # And an array reference binds tighter in the syntax, so goes first;
205 # there's no way to spell "indirection, then array reference".
206 check_expand '${!a[1]}' xx
207 b=(aoeu a)
208 check_expand '${!b[1]}' asdf # i.e. like !(b[1]), not (!b)[1]
209 #
210 # Allowed: apparently everything else.
211 y=yy; yy=
212 check_expand '${!y:-foo}' foo
213 check_expand '${!x:-foo}' aaabcc
214
215 check_expand '${!x:?oops}' aaabcc
216
217 check_expand '${!y:+foo}' ''
218 check_expand '${!x:+foo}' foo
219
220 check_expand '${!x:2}' abcc
221 check_expand '${!x:2:2}' ab
222
223 check_expand '${!x#*a}' aabcc
224 check_expand '${!x%%c*}' aaab
225 check_expand '${!x/a*b/d}' dcc
226
227 # ^ operator not fully implemented in OSH
228 #check_expand '${!x^a}' Aaabcc
229
230 p=pp; pp='\$ '
231 check_expand '${!p@P}' '$ '
232 echo ok
233 ## stdout: ok
234
235 #### var ref OF array var
236 declare -a badref=(ale bean)
237 echo bad=${!badref}
238 ## status: 1
239 ## STDOUT:
240 ## END
241 ## OK bash status: 0
242 ## OK bash stdout: bad=
243
244 #### array ref without eval_unsafe_arith
245 shopt -s compat_array
246
247 declare -a array=(ale bean)
248 ref='array[0]'
249 echo ${!ref}
250 ## status: 1
251 ## stdout-json: ""
252 ## N-I bash status: 0
253 ## N-I bash STDOUT:
254 ale
255 ## END
256
257 #### array ref without compat_array
258 shopt -s eval_unsafe_arith
259
260 declare -a array=(ale bean)
261 ref='array'
262 echo ${!ref}
263 ## status: 1
264 ## stdout-json: ""
265 ## N-I bash status: 0
266 ## N-I bash STDOUT:
267 ale
268 ## END
269
270 #### var ref TO array var
271 shopt -s eval_unsafe_arith compat_array
272
273 declare -a array=(ale bean)
274
275 ref='array' # when compat_array is on, this is like array[0]
276 ref_AT='array[@]'
277
278 echo ${!ref}
279 echo ${!ref_AT}
280
281 ## STDOUT:
282 ale
283 ale bean
284 ## END
285
286 #### var ref TO array var, with subscripts
287 shopt -s eval_unsafe_arith
288
289 f() {
290 argv.py "${!1}"
291 }
292 f 'nonexistent[0]'
293 array=(x y z)
294 f 'array[0]'
295 f 'array[1+1]'
296 f 'array[@]'
297 f 'array[*]'
298 # Also associative arrays.
299 ## STDOUT:
300 ['']
301 ['x']
302 ['z']
303 ['x', 'y', 'z']
304 ['x y z']
305 ## END
306
307 #### var ref TO assoc array a[key]
308 shopt -s eval_unsafe_arith compat_array
309
310 declare -A assoc=([ale]=bean [corn]=dip)
311 ref=assoc
312 #ref_AT='assoc[@]'
313
314 # UNQUOTED doesn't work with Oil's parser
315 #ref_SUB='assoc[ale]'
316 ref_SUB='assoc["ale"]'
317
318 ref_SUB_QUOTED='assoc["al"e]'
319
320 ref_SUB_BAD='assoc["bad"]'
321
322 echo ref=${!ref} # compat_array: assoc is equivalent to assoc[0]
323 #echo ref_AT=${!ref_AT}
324 echo ref_SUB=${!ref_SUB}
325 echo ref_SUB_QUOTED=${!ref_SUB_QUOTED}
326 echo ref_SUB_BAD=${!ref_SUB_BAD}
327
328 ## STDOUT:
329 ref=
330 ref_SUB=bean
331 ref_SUB_QUOTED=bean
332 ref_SUB_BAD=
333 ## END
334
335 #### var ref TO array with arbitrary subscripts
336 shopt -s eval_unsafe_arith compat_array
337
338 f() {
339 local val=$(echo "${!1}")
340 if test "$val" = y; then
341 echo "works: $1"
342 fi
343 }
344 # Warmup: nice plain array reference
345 a=(x y)
346 f 'a[1]'
347 #
348 # Not allowed:
349 # no brace expansion
350 f 'a[{1,0}]' # operand expected
351 # no process substitution (but see command substitution below!)
352 f 'a[<(echo x)]' # operand expected
353 # TODO word splitting seems interesting
354 aa="1 0"
355 f 'a[$aa]' # 1 0: syntax error in expression (error token is "0")
356 # no filename globbing
357 f 'a[b*]' # operand expected
358 f 'a[1"]' # bad substitution
359 #
360 # Allowed: most everything else in section 3.5 "Shell Expansions".
361 # shell parameter expansion
362 b=1
363 f 'a[$b]'
364 f 'a[${c:-1}]'
365 # (... and presumably most of the other features there)
366 # command substitution, yikes!
367 f 'a[$(echo 1)]'
368 # arithmetic expansion
369 f 'a[$(( 3 - 2 ))]'
370
371 # All of these are undocumented and probably shouldn't exist,
372 # though it's always possible some will turn up in the wild and
373 # we'll end up implementing them.
374
375 ## STDOUT:
376 works: a[1]
377 works: a[$b]
378 works: a[${c:-1}]
379 works: a[$(echo 1)]
380 works: a[$(( 3 - 2 ))]
381 ## END
382
383 #### Bizarre tilde expansion in array index
384 a=(x y)
385 PWD=1
386 ref='a[~+]'
387 echo ${!ref}
388 ## status: 1
389 ## BUG bash status: 0
390 ## BUG bash STDOUT:
391 y
392 ## END
393
394 #### Indirect expansion TO fancy expansion features bash disallows
395 shopt -s eval_unsafe_arith
396
397 check_indir() {
398 result="${!1}"
399 desugared_result=$(eval 'echo "${'"$1"'}"')
400 [ "$2" = "$desugared_result" ] || { echo "$1 $desugared_result"; }
401 }
402 x=y
403 y=a
404 a=(x y)
405 declare -A aa
406 aa=([k]=r [l]=s)
407 # malformed array indexing
408 check_indir "a[0"
409 check_indir "aa[k"
410 # double indirection
411 check_indir "!x" a
412 check_indir "!a[0]" y
413 # apparently everything else in the manual under "Shell Parameter Expansion"
414 check_indir "x:-foo" y
415 check_indir "x:=foo" y
416 check_indir "x:?oops" y
417 check_indir "x:+yy" yy
418 check_indir "x:0" y
419 check_indir "x:0:1" y
420 check_indir "!a@" "a aa"
421 # (!a[@] is elsewhere)
422 check_indir "#x" 1
423 check_indir "x#y"
424 check_indir "x/y/foo" foo
425 check_indir "x@Q" "'y'"
426 echo done
427 ## status: 1
428 ## stdout-json: ""
429 ## OK bash status: 0
430 ## OK bash stdout: done
431
432 #### Bad var ref
433 a='bad var name'
434 echo ref ${!a}
435 echo status=$?
436
437 ## STDOUT:
438 status=1
439 ## END
440 ## OK osh stdout-json: ""
441 ## OK osh status: 1
442
443 #### Bad var ref 2
444 b='/' # really bad
445 echo ref ${!b}
446 echo status=$?
447 ## STDOUT:
448 status=1
449 ## END
450 ## OK osh stdout-json: ""
451 ## OK osh status: 1
452
453 #### ${!OPTIND} (used by bash completion
454 set -- a b c
455 echo ${!OPTIND}
456 f() {
457 local OPTIND=1
458 echo ${!OPTIND}
459 local OPTIND=2
460 echo ${!OPTIND}
461 }
462 f x y z
463 ## STDOUT:
464 a
465 x
466 y
467 ## END
468
469 #### var ref doesn't need cycle detection
470 x=y
471 y=x
472 echo cycle=${!x}
473
474 typeset -n a=b
475 typeset -n b=a
476 echo cycle=${a}
477 ## status: 1
478 ## STDOUT:
479 cycle=x
480 ## END
481 ## OK bash status: 0
482 ## OK bash STDOUT:
483 cycle=x
484 cycle=
485 ## END