英文:
if-else undefined variable compile error
问题
在这个代码示例中，编译器会报一个undefined: something的错误。由于这是一个if else语句，something变量将在运行时定义，但编译器无法检测到这一点。
你可以如何避免这个编译错误？这个问题在下一个版本中会被修复吗？
英文:
if someCondition() {
something := getSomething()
} else {
something := getSomethingElse()
}
print(something)
in this code example, compiler gives an undefined: something error. Since this is an if else statement something variable will be defined in the runtime, but compiler fails detect this.
How can I avoid this compile error, also will this be fixed in the next versions?
答案1
得分: 1
两个 something 变量是具有不同作用域的两个不同变量。它们在 if/else 块作用域之外不存在，这就是为什么会出现未定义错误。
你需要在 if 语句之外定义该变量，可以像这样：
var something string
if someCondition() {
something = getSomething()
} else {
something = getSomethingElse()
}
print(something)
英文:
The two something variables are two different variables with different scopes. They do not exist outside the if/else block scope which is why you get an undefined error.
You need to define the variable outside the if statement with something like this:
var something string
if someCondition() {
something = getSomething()
} else {
something = getSomethingElse()
}
print(something)
答案2
得分: 1
在你的代码片段中，你定义了两个 something 变量，它们的作用域限定在 if 语句的每个块内。
相反，你想要一个作用域在 if 语句之外的单个变量：
var something sometype
if someCondition() {
something = getSomething()
} else {
something = getSomethingElse()
}
print(something)
英文:
In your code fragment, you're defining two something variables scoped to each block of the if statement.
Instead, you want a single variable scoped outside of the if statement:
var something sometype
if someCondition() {
something = getSomething()
} else {
something = getSomethingElse()
}
print(something)
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