StringPrepareExpression

Func StringPrepareExpression($s, $d=False)
    Local a = StringRegExpReplace, b = StringReplace
    If $d Then ConsoleWrite("!!!  " & $s & @CRLF) ; debug
    Local $v = StringRegExp($s, "\(([^()]+)\)", 3), $i, $f
    If (Not @error) Then
        For $i = 0 To UBound($v)-1
            $s = StringReplace($s, "(" & $v[$i] & ")", "[$var" & $i & "]", 1, 1)
            If $d Then ConsoleWrite("!!!  " & $v[$i] & " --> " & "$var" & $i & @CRLF) ; debug
        Next
        If $d Then ConsoleWrite("!!!  " & $s & @CRLF) ; debug
        If (StringInStr($s, "(") > 0) Then $s = StringPrepareExpression($s, $d)
    EndIf
    ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
    Local $x = ".+?"
    $s = "(" & $s & ")"
    $s = a($s, b("\(\s*(x)\s*\+\s*(x)\s*\)", "x", $x), "Add[(\1), (\2)]")
    $s = a($s, b("\(\s*(x)\s*\-\s*(x)\s*\)", "x", $x), "Sub[(\1), (\2)]")
    $s = a($s, b("\(\s*(x)\s*\*\s*(x)\s*\)", "x", $x), "Mul[(\1), (\2)]")
    $s = a($s, b("\(\s*(x)\s*\/\s*(x)\s*\)", "x", $x), "Div[(\1), (\2)]")
    $s = a($s, b("\(\s*(x)\s*\%\s*(x)\s*\)", "x", $x), "Mod[(\1), (\2)]")
    $s = a($s, b("\(\s*(x)\s*\^\s*(x)\s*\)", "x", $x), "Pow[(\1), (\2)]")
    $s = StringReplace($s, "[", "(")
    $s = StringReplace($s, "]", ")")
    ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
    If $d Then ConsoleWrite("!!!  " & $s & @CRLF) ; debug
    If IsArray($v) Then
        For $i = 0 To UBound($v)-1
            $f = StringPrepareExpression($v[$i])
;~          $s = StringReplace($s, "$var" & $i, $f)
            $s = StringReplace($s, "($var" & $i & ")", $f)
            If $d Then ConsoleWrite("!!!  $var" & $i & " --> " & $f & @CRLF) ; debug
        Next
    EndIf
    If $d Then ConsoleWrite("!!!  " & $s & @CRLF) ; debug
    Return $s
EndFunc