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]