1	#!/usr/bin/env bash
2	#
3	# Test arithmetic expressions in all their different contexts.
4
5	# $(( 1 + 2 ))
6	# (( a=1+2 ))
7	# ${a[ 1 + 2 ]}
8	# ${a : 1+2 : 1+2}
9	# a[1 + 2]=foo
10
11	### Multiple right brackets inside expression
12	a=(1 2 3)
13	echo ${a[a[0]]} ${a[a[a[0]]]}
14	# stdout: 2 3
15	# N-I zsh status: 0
16	# N-I zsh stdout-json: "\n"
17
18	### Slicing of string with constants
19	s='abcd'
20	echo ${s:0} ${s:0:4} ${s:1:1}
21	# stdout: abcd abcd b
22
23	### Slicing of string with variables
24	s='abcd'
25	zero=0
26	one=1
27	echo ${s:$zero} ${s:$zero:4} ${s:$one:$one}
28	# stdout: abcd abcd b
29
30	### Array index on LHS of assignment
31	a=(1 2 3)
32	zero=0
33	a[zero+5-4]=X
34	echo ${a[@]}
35	# stdout: 1 X 3
36	# OK zsh stdout: X 2 3
37
38	### Array index on LHS with spaces
39	# zsh fails to parse this because of the spaces.
40	a=(1 2 3)
41	zero=0
42	a[zero + 5 - 4]=X
43	echo ${a[@]}
44	# stdout: 1 X 3
45	# BUG zsh stdout-json: ""
46	# BUG zsh status: 1
47
48	### Array index on LHS with indices
49	a=(1 2 3)
50	a[a[1]]=X
51	echo ${a[@]}
52	# stdout: 1 2 X
53	# OK zsh stdout: X 2 3
54
55	### Slicing of string with expressions
56	# mksh accepts ${s:0} and ${s:$zero} but not ${s:zero}
57	# zsh says unrecognized modifier 'z'
58	s='abcd'
59	zero=0
60	echo ${s:zero} ${s:zero+0} ${s:zero+1:zero+1}
61	# stdout: abcd abcd b
62	# BUG mksh stdout-json: ""
63	# BUG mksh status: 1
64	# BUG zsh stdout-json: ""
65	# BUG zsh status: 1
66
67	### Ambiguous colon in slice
68	s='abcd'
69	echo $(( 0 < 1 ? 2 : 0 )) # evalutes to 2
70	echo ${s: 0 < 1 ? 2 : 0 : 1} # 2:1 -- TRICKY THREE COLONS
71	# stdout-json: "2\nc\n"
72	# BUG mksh stdout-json: "2\n"
73	# BUG mksh status: 1
74	# BUG zsh stdout-json: "2\n"
75	# BUG zsh status: 1
76
77	### Triple parens should be disambiguated
78	# The first paren is part of the math, parens 2 and 3 are a single token ending
79	# arith sub.
80	((a=1 + (2*3)))
81	echo $a $((1 + (2*3)))
82	# stdout: 7 7
83
84	### Quadruple parens should be disambiguated
85	((a=1 + (2 * (3+4))))
86	echo $a $((1 + (2 * (3+4))))
87	# stdout: 15 15
88
89	### Alternative $[] syntax
90	echo $[1 + 2] "$[3 * 4]"
91	# stdout: 3 12
92	# N-I mksh stdout: $[1 + 2] $[3 * 4]