1 #!/usr/bin/env bash
2
3 ### Lazy Evaluation of Alternative
4 i=0
5 x=x
6 echo ${x:-$((i++))}
7 echo $i
8 echo ${undefined:-$((i++))}
9 echo $i # i is one because the alternative was only evaluated once
10 # status: 0
11 # stdout-json: "x\n0\n0\n1\n"
12 # N-I dash status: 2
13 # N-I dash stdout-json: "x\n0\n"
14
15 ### Default value when empty
16 empty=''
17 echo ${empty:-is empty}
18 # stdout: is empty
19
20 ### Default value when unset
21 echo ${unset-is unset}
22 # stdout: is unset
23
24 ### Unquoted with array as default value
25 set -- '1 2' '3 4'
26 argv.py X${unset=x"$@"x}X
27 # stdout: ['Xx1', '2', '3', '4xX']
28
29 ### Quoted with array as default value
30 set -- '1 2' '3 4'
31 argv.py "X${unset=x"$@"x}X"
32 # stdout: ['Xx1 2 3 4xX']
33 # BUG bash stdout: ['Xx1', '2', '3', '4xX']
34
35 ### Assign default value when empty
36 empty=''
37 ${empty:=is empty}
38 echo $empty
39 # stdout: is empty
40
41 ### Assign default value when unset
42 ${unset=is unset}
43 echo $unset
44 # stdout: is unset
45
46 ### Assign default with array
47 # HMMMM osh stdout-json: "['Xx1 2', '3 4xX']\n['x1 2 3 4x']\n"
48 # I think OSH diverges here because VTest is different than VOp1?
49 # I parse all the arg words the same way.
50 set -- '1 2' '3 4'
51 argv.py X${unset=x"$@"x}X
52 argv.py "$unset"
53 # stdout-json: "['Xx1', '2', '3', '4xX']\n['x1 2 3 4x']\n"
54
55 ### Alternative value when empty
56 v=foo
57 empty=''
58 echo ${v:+v is not empty} ${empty:+is not empty}
59 # stdout: v is not empty
60
61 ### Alternative value when unset
62 v=foo
63 echo ${v+v is not unset} ${unset:+is not unset}
64 # stdout: v is not unset
65
66 ### Error when empty
67 empty=''
68 ${empty:?is empty}
69 # status: 1
70 # OK dash status: 2
71
72 ### Error when unset
73 ${unset?is empty}
74 # status: 1
75 # OK dash status: 2
76
77 ### Error when unset
78 v=foo
79 echo ${v+v is not unset} ${unset:+is not unset}
80 # stdout: v is not unset