1	#!/usr/bin/env bash
2	#
3	# Var refs are done with ${!a} and local/declare -n.
4	#
5	# http://stackoverflow.com/questions/16461656/bash-how-to-pass-array-as-an-argument-to-a-function
6
7	#### var ref ${!a}
8	a=b
9	b=c
10	echo ref ${!a} ${a}
11	# Woah mksh has a completely different behavior -- var name, not var ref.
12	## stdout: ref c b
13	## BUG mksh stdout: ref a b
14	## N-I dash/zsh stdout-json: ""
15
16	#### var ref with special vars
17	myfunc() {
18	local ref=$1
19	echo ${!ref}
20	}
21	myfunc FUNCNAME
22	myfunc '?' # osh doesn't do this dynamically
23	## stdout-json: "myfunc\n0\n"
24	## N-I mksh stdout-json: "ref\nref\n"
25
26	#### declare -n and ${!a}
27	declare -n a
28	a=b
29	b=c
30	echo ${!a} ${a}
31	## stdout: b c
32	## N-I mksh stdout: a b
33
34	#### Bad var ref with ${!a}
35	#set -o nounset
36	a='bad var name'
37	echo ref ${!a}
38	echo status=$?
39	## STDOUT:
40	status=1
41	## END
42	## BUG mksh STDOUT:
43	ref a
44	status=0
45	## END
46
47	#### pass array by reference
48	show_value() {
49	local -n array=$1
50	local idx=$2
51	echo "${array[$idx]}"
52	}
53	shadock=(ga bu zo meu)
54	show_value shadock 2
55	## stdout: zo
56
57	#### pass assoc array by reference
58	show_value() {
59	local -n array=$1
60	local idx=$2
61	echo "${array[$idx]}"
62	}
63	days=([monday]=eggs [tuesday]=bread [sunday]=jam)
64	show_value days sunday
65	## stdout: jam
66	## BUG mksh stdout: [monday]=eggs
67	# mksh note: it coerces "days" to 0? Horrible.
68
69	#### pass local array by reference, relying on DYNAMIC SCOPING
70	show_value() {
71	local -n array=$1
72	local idx=$2
73	echo "${array[$idx]}"
74	}
75	caller() {
76	local shadock=(ga bu zo meu)
77	show_value shadock 2
78	}
79	caller
80	## stdout: zo
81	# mksh appears not to hav elocal arrays!
82	## BUG mksh stdout-json: ""
83	## BUG mksh status: 1
84
85	#### ${!OPTIND} (used by bash completion
86	set -- a b c
87	echo ${!OPTIND}
88	f() {
89	local OPTIND=1
90	echo ${!OPTIND}
91	local OPTIND=2
92	echo ${!OPTIND}
93	}
94	f x y z
95	## STDOUT:
96	a
97	x
98	y
99	## END
100	## N-I mksh STDOUT:
101	OPTIND
102	OPTIND
103	OPTIND
104	## END