Created
April 3, 2020 12:24
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MaybeHash
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| class Some | |
| def initialize(value) | |
| @value = value | |
| end | |
| def value | |
| @value | |
| end | |
| end | |
| class None | |
| def initialize | |
| end | |
| def value | |
| raise "error" | |
| end | |
| end | |
| class MaybeHash | |
| def initialize(hash) | |
| @hash = hash | |
| end | |
| def [](key) | |
| if @hash.has_key?(key) | |
| Some.new(@hash[key]) | |
| else | |
| None.new() | |
| end | |
| end | |
| end | |
| hash = { | |
| key: :value | |
| } | |
| hash = MaybeHash.new(hash) | |
| pp hash[:key] | |
| pp hash[:unknown_key] |
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