2021年1月8日(金) 20:07 Oğuz <oguzismailuy...@gmail.com>: > On Fri, Jan 8, 2021 at 2:14 PM Koichi Murase <myoga.mur...@gmail.com> wrote: >> There is no reason to introduce a different expansion rule of >> `((...))' from that of `$((...))'. > > But there already is a different expansion rule. While `(( > assoc['$key']++ ))' works, `: $(( assoc['$key']++ ))' fails with a > bad subscript error.
Actually, that inconsistency has been fixed in Bash 5.1 to match with the behavior of `$(( assoc['$key']++ ))', i.e., now in Bash 5.1, `(( assoc['$key']++ ))' doesn't work either. So, `(( assoc[\$key]++ ))' is the only working way to access the associative array in the arithmetic command of the form `(( ... ))'. Or, maybe you could write `let 'assoc[$key]++'`. -- Koichi
