Question

我有这个REBOL脚本：

REBOL [Title: "Employee list"]

emp-list: [
    "Amy" 1
    "Bob" 2
    "Carrie" 3
]

gui-layout: [ text "click to reveal number" ]

foreach [name id] emp-list [
    append gui-layout [
        box name [print id]
    ]
]

view layout gui-layout

奇怪的是，对我而言，它创建了一个带有三个Carries的窗口，点击时打印3。我在这里做错了什么？

Answer 1

>> probe gui-layout

[text "click to reveal number"
box name [print id]
box name [print id]
box name [print id]
]

Rebol只需将行box name [print id]附加到'gui-layout，而不进行评估，在FOREACH循环之后，'name指向"Carrie"，'id指向3。

为避免这种情况，您可以像这样替换FOREACH循环：

foreach [name id] emp-list [
    append gui-layout compose/deep [
        box (name) [print (id)]
    ]
]

并在此循环之后：

>> probe gui-layout

[text "click to reveal number"
box
"Amy" [print 1]
box
"Bob" [print 2]
box
"Carrie" [print 3]
]

为什么foreach追加只取最后一项？

1 个答案: