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#!/usr/bin/env bash |
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|
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#### Lazy Evaluation of Alternative |
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i=0 |
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x=x |
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echo ${x:-$((i++))} |
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echo $i |
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echo ${undefined:-$((i++))} |
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echo $i # i is one because the alternative was only evaluated once |
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## status: 0 |
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## stdout-json: "x\n0\n0\n1\n" |
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## N-I dash status: 2 |
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## N-I dash stdout-json: "x\n0\n" |
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|
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#### Default value when empty |
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empty='' |
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echo ${empty:-is empty} |
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## stdout: is empty |
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|
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#### Default value when unset |
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echo ${unset-is unset} |
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## stdout: is unset |
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|
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#### Unquoted with array as default value |
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set -- '1 2' '3 4' |
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argv.py X${unset=x"$@"x}X |
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argv.py X${unset=x$@x}X # If you want OSH to split, write this |
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# osh |
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## STDOUT: |
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['Xx1', '2', '3', '4xX'] |
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['Xx1', '2', '3', '4xX'] |
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## END |
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## OK osh STDOUT: |
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['Xx1 2', '3 4xX'] |
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['Xx1', '2', '3', '4xX'] |
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## END |
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|
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#### Quoted with array as default value |
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set -- '1 2' '3 4' |
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argv.py "X${unset=x"$@"x}X" |
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argv.py "X${unset=x$@x}X" # OSH is the same here |
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## STDOUT: |
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['Xx1 2 3 4xX'] |
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['Xx1 2 3 4xX'] |
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## END |
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## BUG bash STDOUT: |
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['Xx1', '2', '3', '4xX'] |
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['Xx1 2 3 4xX'] |
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## END |
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## OK osh STDOUT: |
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['Xx1 2', '3 4xX'] |
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['Xx1 2 3 4xX'] |
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## END |
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|
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#### Assign default with array |
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set -- '1 2' '3 4' |
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argv.py X${unset=x"$@"x}X |
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argv.py "$unset" |
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## STDOUT: |
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['Xx1', '2', '3', '4xX'] |
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['x1 2 3 4x'] |
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## END |
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## OK osh STDOUT: |
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['Xx1 2', '3 4xX'] |
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['x1 2 3 4x'] |
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## END |
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|
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#### Assign default value when empty |
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empty='' |
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${empty:=is empty} |
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echo $empty |
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## stdout: is empty |
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|
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#### Assign default value when unset |
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${unset=is unset} |
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echo $unset |
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## stdout: is unset |
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|
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#### Alternative value when empty |
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v=foo |
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empty='' |
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echo ${v:+v is not empty} ${empty:+is not empty} |
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## stdout: v is not empty |
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|
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#### Alternative value when unset |
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v=foo |
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echo ${v+v is not unset} ${unset:+is not unset} |
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## stdout: v is not unset |
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|
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#### Error when empty |
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empty='' |
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echo ${empty:?'is em'pty} # test eval of error |
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echo should not get here |
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## stdout-json: "" |
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## status: 1 |
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## OK dash status: 2 |
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|
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#### Error when unset |
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echo ${unset?is empty} |
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echo should not get here |
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## stdout-json: "" |
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## status: 1 |
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## OK dash status: 2 |
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|
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#### Error when unset |
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v=foo |
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echo ${v+v is not unset} ${unset:+is not unset} |
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## stdout: v is not unset |
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|
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#### ${var=x} dynamic scope |
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f() { : "${hello:=x}"; echo $hello; } |
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f |
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echo hello=$hello |
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|
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f() { hello=x; } |
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f |
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echo hello=$hello |
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## STDOUT: |
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x |
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hello=x |
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hello=x |
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## END |
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|
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#### array ${arr[0]=x} |
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arr=() |
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echo ${#arr[@]} |
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: ${arr[0]=x} |
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echo ${#arr[@]} |
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## STDOUT: |
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0 |
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1 |
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## END |
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## N-I dash status: 2 |
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## N-I dash stdout-json: "" |
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|
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#### assoc array ${arr["k"]=x} |
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# note: this also works in zsh |
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|
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declare -A arr=() |
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echo ${#arr[@]} |
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: ${arr['k']=x} |
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echo ${#arr[@]} |
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## STDOUT: |
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0 |
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1 |
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## END |
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## N-I dash status: 2 |
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## N-I dash stdout-json: "" |
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## N-I mksh status: 1 |
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## N-I mksh stdout-json: "" |
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|
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#### "\z" as arg |
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echo "${undef-\$}" |
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echo "${undef-\(}" |
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echo "${undef-\z}" |
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echo "${undef-\"}" |
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echo "${undef-\`}" |
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echo "${undef-\\}" |
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## STDOUT: |
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$ |
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\( |
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\z |
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" |
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` |
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\ |
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## END |
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## BUG yash STDOUT: |
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$ |
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( |
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z |
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" |
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` |
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\ |
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## END |
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|
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#### "\e" as arg |
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echo "${undef-\e}" |
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## STDOUT: |
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\e |
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## END |
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## BUG zsh/mksh stdout-repr: '\x1b\n' |
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## BUG yash stdout: e |
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