使用 TAB 在 Red 语言的字段之间移动

Using TAB to move between fields in Red language

我有以下简单代码:

Red []
view [
    text "Value of x:"  f1: field "" return
    text "Value of y:"  f2: field "" return
    text "Read Sum:"    tt: text ""  return
    button "Calculate" [
        tt/text: to-string ((to-integer f1/text) + (to-integer f2/text)) ]
    button "Quit" [quit]  ]

如何添加代码以便可以使用 TAB 键在不同字段之间移动?显然,这在 Rebol ( http://www.rebol.com/how-to/fields.html ) 中有效,但在这里不起作用。

根据gitter archive

handle-key: function [e prev-fld next-fld][
    k: e/key
    if k = tab [
        either e/shift? [win/selected: prev-fld][win/selected: next-fld]
    ]
]
view [
    text "Value of x:"  f1: field "" on-key [handle-key event tt  f2] return
    text "Value of y:"  f2: field "" on-key [handle-key event f1  tt] return
    text "Read Sum:"    tt: text ""  on-key [handle-key event f2  f1] return
    button "Calculate" [
        tt/text: to-string ((to-integer f1/text) + (to-integer f2/text))      
    ]
    button "Quit" [quit]  
    do [win: self win/selected: f1]
]