29 lines
892 B
Plaintext
29 lines
892 B
Plaintext
# this captures how bash and ksh93 expand indexed array subscripts in
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# various contexts. if changes are ever made, or an option added to do
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# this differently, the diffs will show up here
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typeset -a array
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index='$( echo >&2 foo )' # Literal shell code should never be evaluated unless an 'eval' is involved.
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echo ${array[ $index ]} # [] expands $index, results in a literal that [] does not re-evaluate.
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echo $(( $index )) # (( )) expands $index, results in a literal that (( )) does not re-evaluate.
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echo $(( array[ $index ] )) # (( )) expands $index, results in a literal that [] DOES re-evaluate.
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(( array[ $index ] ))
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typeset -a a
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: $(( a[$index]=5 ))
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#shopt -s assoc_expand_once
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echo $((1+a[$index]))
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echo $((1+a[\$index]))
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echo "1+${a[$index]}"
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# intermediate problems discovered while bash-5.0 was in testing
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a=0
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echo $(( a[a[0]] ))
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echo ${a[a[a[0]]]}
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echo $(( a[a[a[0]]] ))
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