1 while $line =~ s/(\p{IsWord})(?<!\p{IsSpace}AND|\p{IsSpace}XOR|\p{IsSpace}NOT|\p{IsWord}\p{IsSpace}OR)(\p{IsSpace}|\s|\p{IsMc}|\p{IsZs}|\p{IsZ})(?!AND\p{IsSpace}|XOR\p{IsSpace}|NOT\p{IsSpace}|\&\&|\&\p{IsSpace}|\+|\|\||\||OR\p{IsSpace}|\^|\!)(\p{IsWord})/$1 AND $3/gi;