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28 lines
1.0 KiB
Markdown
28 lines
1.0 KiB
Markdown
# Break Out Of A While Loop
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The `while` construct is a great way to loop indefinitely. You may
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eventually want to break out of the loop. For that, you are going to need to
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invalidate the _while condition_. One way of going about this is creating a
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mutable ref, changing it from true to false when a certain condition is met.
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```reason
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let break = ref(true);
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while (break^) {
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switch (Unix.readdir(currentDir)) {
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| exception End_of_file => break := false
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| item => print_endline(item);
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}
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};
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```
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Here we have a mutable ref called `break` which starts as `true`. This is
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our _while condition_. Its actual value can be referenced by appending the
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`^` character -- hence `break^`. Once a certain condition is met inside our
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`while` block, we can set `break` to `false` using the `:=` operator.
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The above code snippet can be seen in full details
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[here](https://github.com/jbranchaud/basic-ls-reason-native/blob/master/src/Index.re).
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[source](https://reasonml.github.io/docs/en/imperative-loops.html#tips-tricks)
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