1	#
2	# Arrays decay upon assignment (without splicing) and equality. This will not
3	# be true in Oil -- arrays will be first class.
4
5	#### Assignment Causes Array Decay
6	set -- x y z
7	argv.py "[$@]"
8	var="[$@]"
9	argv.py "$var"
10	## STDOUT:
11	['[x', 'y', 'z]']
12	['[x y z]']
13	## END
14
15	#### Array Decay with IFS
16	IFS=x
17	set -- x y z
18	var="[$@]"
19	argv.py "$var"
20	## stdout: ['[x y z]']
21
22	#### User arrays decay
23	declare -a a b
24	a=(x y z)
25	b="${a[@]}" # this collapses to a string
26	c=("${a[@]}") # this preserves the array
27	c[1]=YYY # mutate a copy -- doesn't affect the original
28	argv.py "${a[@]}"
29	argv.py "${b}"
30	argv.py "${c[@]}"
31	## STDOUT:
32	['x', 'y', 'z']
33	['x y z']
34	['x', 'YYY', 'z']
35	## END
36
37	#### strict_array: $array is not valid in OSH, is ${array[0]} in ksh/bash
38	shopt -s strict_array
39
40	a=(1 '2 3')
41	echo $a
42	## STDOUT:
43	1
44	## END
45	## OK osh status: 1
46	## OK osh stdout-json: ""
47
48	#### strict_array: ${array} is not valid in OSH, is ${array[0]} in ksh/bash
49	shopt -s strict_array
50
51	a=(1 '2 3')
52	echo ${a}
53	## STDOUT:
54	1
55	## END
56	## OK osh status: 1
57	## OK osh stdout-json: ""
58
59	#### Assign to array index without initialization
60	a[5]=5
61	a[6]=6
62	echo "${a[@]}" ${#a[@]}
63	## stdout: 5 6 2
64
65	#### a[40] grows array
66	a=(1 2 3)
67	a[1]=5
68	a[40]=30 # out of order
69	a[10]=20
70	echo "${a[@]}" "${#a[@]}" # length is 1
71	## stdout: 1 5 3 20 30 5
72
73	#### array decays to string when comparing with [[ a = b ]]
74	a=('1 2' '3 4')
75	s='1 2 3 4' # length 2, length 4
76	echo ${#a[@]} ${#s}
77	[[ "${a[@]}" = "$s" ]] && echo EQUAL
78	## STDOUT:
79	2 7
80	EQUAL
81	## END
82
83	#### ++ on a whole array increments the first element (disallowed with strict_array)
84	shopt -s strict_array
85
86	a=(1 10)
87	(( a++ )) # doesn't make sense
88	echo "${a[@]}"
89	## stdout: 2 10
90	## OK osh status: 1
91	## OK osh stdout-json: ""
92
93	#### Apply vectorized operations on ${a[*]}
94	a=('-x-' 'y-y' '-z-')
95
96	# This does the prefix stripping FIRST, and then it joins.
97	argv.py "${a[*]#-}"
98	## STDOUT:
99	['x- y-y z-']
100	## END
101	## N-I mksh status: 1
102	## N-I mksh stdout-json: ""