1 |
|
2 |
#### recursive arith: one level |
3 |
shopt -s eval_unsafe_arith |
4 |
a='b=123' |
5 |
echo $((a)) |
6 |
## stdout: 123 |
7 |
## N-I dash status: 2 |
8 |
## N-I dash stdout-json: "" |
9 |
## N-I yash stdout: b=123 |
10 |
|
11 |
#### recursive arith: two levels |
12 |
shopt -s eval_unsafe_arith |
13 |
a='b=c' c='d=123' |
14 |
echo $((a)) |
15 |
## stdout: 123 |
16 |
## N-I dash status: 2 |
17 |
## N-I dash stdout-json: "" |
18 |
## N-I yash stdout: b=c |
19 |
|
20 |
#### recursive arith: short circuit &&, || |
21 |
# Note: mksh R52 has a bug. Even though it supports a short circuit like |
22 |
# "echo $((cond&&(a=1)))", it doesn't work with "x=a=1; echo |
23 |
# $((cond&&x))". It is fixed at least in mksh R57. |
24 |
# Note: "busybox sh" doesn't support short circuit. |
25 |
shopt -s eval_unsafe_arith |
26 |
a=b=123 |
27 |
echo $((1||a)):$((b)) |
28 |
echo $((0||a)):$((b)) |
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c=d=321 |
30 |
echo $((0&&c)):$((d)) |
31 |
echo $((1&&c)):$((d)) |
32 |
## stdout-json: "1:0\n1:123\n0:0\n1:321\n" |
33 |
## BUG mksh stdout-json: "1:123\n1:123\n0:321\n1:321\n" |
34 |
## N-I ash stdout-json: "1:123\n1:123\n0:321\n1:321\n" |
35 |
## N-I dash/yash status: 2 |
36 |
## N-I dash/yash stdout-json: "1:0\n" |
37 |
|
38 |
#### recursive arith: short circuit ?: |
39 |
# Note: "busybox sh" behaves strangely. |
40 |
shopt -s eval_unsafe_arith |
41 |
y=a=123 n=a=321 |
42 |
echo $((1?(y):(n))):$((a)) |
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echo $((0?(y):(n))):$((a)) |
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## STDOUT: |
45 |
123:123 |
46 |
321:321 |
47 |
## END |
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## BUG ash STDOUT: |
49 |
123:321 |
50 |
321:321 |
51 |
## END |
52 |
## N-I dash status: 2 |
53 |
## N-I dash stdout-json: "" |
54 |
## N-I yash STDOUT: |
55 |
a=123:0 |
56 |
a=321:0 |
57 |
## END |
58 |
|
59 |
#### recursive arith: side effects |
60 |
# In Zsh and Busybox sh, the side effect of inner arithmetic |
61 |
# evaluations seems to take effect only after the whole evaluation. |
62 |
shopt -s eval_unsafe_arith |
63 |
a='b=c' c='d=123' |
64 |
echo $((a,d)):$((d)) |
65 |
## stdout: 123:123 |
66 |
## BUG zsh/ash stdout: 0:123 |
67 |
## N-I dash/yash status: 2 |
68 |
## N-I dash/yash stdout-json: "" |
69 |
|
70 |
#### recursive arith: recursion |
71 |
shopt -s eval_unsafe_arith |
72 |
loop='i<=100&&(s+=i,i++,loop)' s=0 i=0 |
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echo $((a=loop,s)) |
74 |
## stdout: 5050 |
75 |
## N-I mksh status: 1 |
76 |
## N-I mksh stdout-json: "" |
77 |
## N-I ash/dash/yash status: 2 |
78 |
## N-I ash/dash/yash stdout-json: "" |
79 |
|
80 |
#### recursive arith: array elements |
81 |
shopt -s eval_unsafe_arith |
82 |
text[1]='d=123' |
83 |
text[2]='text[1]' |
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text[3]='text[2]' |
85 |
echo $((a=text[3])) |
86 |
## stdout: 123 |
87 |
## N-I ash/dash/yash status: 2 |
88 |
## N-I ash/dash/yash stdout-json: "" |
89 |
|
90 |
#### dynamic arith varname: assign |
91 |
shopt -s parse_dynamic_arith # for LHS |
92 |
|
93 |
vec2_set () { |
94 |
local this=$1 x=$2 y=$3 |
95 |
: $(( ${this}_x = $2 )) |
96 |
: $(( ${this}_y = y )) |
97 |
} |
98 |
vec2_set a 3 4 |
99 |
vec2_set b 5 12 |
100 |
echo a_x=$a_x a_y=$a_y |
101 |
echo b_x=$b_x b_y=$b_y |
102 |
## STDOUT: |
103 |
a_x=3 a_y=4 |
104 |
b_x=5 b_y=12 |
105 |
## END |
106 |
|
107 |
#### dynamic arith varname: read |
108 |
shopt -s eval_unsafe_arith # for RHS |
109 |
|
110 |
vec2_load() { |
111 |
local this=$1 |
112 |
x=$(( ${this}_x )) |
113 |
: $(( y = ${this}_y )) |
114 |
} |
115 |
a_x=12 a_y=34 |
116 |
vec2_load a |
117 |
echo x=$x y=$y |
118 |
## STDOUT: |
119 |
x=12 y=34 |
120 |
## END |
121 |
|
122 |
#### dynamic arith varname: copy/add |
123 |
shopt -s parse_dynamic_arith # for LHS |
124 |
shopt -s eval_unsafe_arith # for RHS |
125 |
|
126 |
vec2_copy () { |
127 |
local this=$1 rhs=$2 |
128 |
: $(( ${this}_x = $(( ${rhs}_x )) )) |
129 |
: $(( ${this}_y = ${rhs}_y )) |
130 |
} |
131 |
vec2_add () { |
132 |
local this=$1 rhs=$2 |
133 |
: $(( ${this}_x += $(( ${rhs}_x )) )) |
134 |
: $(( ${this}_y += ${rhs}_y )) |
135 |
} |
136 |
a_x=3 a_y=4 |
137 |
b_x=4 b_y=20 |
138 |
vec2_copy c a |
139 |
echo c_x=$c_x c_y=$c_y |
140 |
vec2_add c b |
141 |
echo c_x=$c_x c_y=$c_y |
142 |
## STDOUT: |
143 |
c_x=3 c_y=4 |
144 |
c_x=7 c_y=24 |
145 |
## END |
146 |
|
147 |
#### is-array with ${var@a} |
148 |
case $SH in (mksh|ash|dash|yash) exit 1 ;; esac |
149 |
|
150 |
function ble/is-array { [[ ${!1@a} == *a* ]]; } |
151 |
|
152 |
ble/is-array undef |
153 |
echo undef $? |
154 |
|
155 |
string='' |
156 |
ble/is-array string |
157 |
echo string $? |
158 |
|
159 |
array=(one two three) |
160 |
ble/is-array array |
161 |
echo array $? |
162 |
## STDOUT: |
163 |
undef 1 |
164 |
string 1 |
165 |
array 0 |
166 |
## END |
167 |
## N-I zsh/mksh/ash/dash/yash status: 1 |
168 |
## N-I zsh/mksh/ash/dash/yash stdout-json: "" |