31 lines
840 B
Markdown
31 lines
840 B
Markdown
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# Optional Values
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A very common use case is values that may or may not be present. You could
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represent this case using enums like so:
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```tomo
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enum MaybeInt(AnInt(x:Int), NoInt)
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func maybe_takes_int(maybe_x:MaybeInt):
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when maybe_x is AnInt(x):
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say("Got an int: $x")
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else:
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say("Got nothing")
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```
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However, it's overly onerous to have to define a separate type for each
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situation where you might want to not have a value. Instead, Tomo has
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built-in support for optional types:
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```
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func maybe_takes_int(x:Int?):
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if x:
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say("Got an int: $x")
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else:
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say("Got nothing")
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```
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This establishes a common language for talking about optional values without
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having to use a more generalized form of `enum` which may have different naming
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conventions and which would generate a lot of unnecessary code.
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