$str =~ s/if substr\(([^\)]*)\) in (\([^\)]*\))/my($f,$s)=($1,$2); $f=~s!^!\$!; $s=~s!\D!!g; "if substr($f) =~ m#[$s]#"/eg;

##</code><code>##

$str =~ s/in/=~/;
$str =~ s/(?:\s)(\([^\)]*\))/my $s=$1;$s=~s!\D!!g;" m#[$s]#"/e;

##</code><code>##

if substr(acct_trtmt_hsty,1,1) =~ m#[789]#;