82 lines
1.9 KiB
GDScript
82 lines
1.9 KiB
GDScript
class_name Option extends RefCounted
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static var Unit = Option.some(null)
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static func some(value: Variant) -> Option:
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return Some.new(value)
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static var none: Option.None = None.new()
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static func collect_some(options: Array[Option], ignore_none: bool = false) -> Option:
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var result = []
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for option in options:
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if option.is_some():
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result.push_back(option.unwrap())
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elif not ignore_none:
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return Option.none
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return Option.some(result)
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class Some extends Option:
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var value: Variant
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func _init(val: Variant) -> void:
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value = val
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func chain(fn: Callable) -> Option:
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return fn.call(value)
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func filter(fn: Callable) -> Option:
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if fn.call(value): return self
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else: return Option.none
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func flatten() -> Option:
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if value is Option:
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return value.flatten()
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else: return Option.some(value)
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func map(fn: Callable) -> Option:
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return Option.some(fn.call(value))
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func is_some() -> bool:
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return true
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func is_none() -> bool:
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return false
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func or_default(_default_value: Variant) -> Variant:
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return value
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func or_else(_fn: Callable) -> Variant:
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return value
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func unwrap() -> Variant:
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return value
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class None extends Option:
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func chain(_fn: Callable) -> Option:
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return self
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func filter(_f: Callable) -> Option:
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return self
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func flatten() -> Option:
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return self
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func map(_fn: Callable) -> Option:
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return self
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func is_some() -> bool:
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return false
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func is_none() -> bool:
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return true
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func or_default(default_value: Variant) -> Variant:
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return default_value
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func or_else(fn: Callable) -> Variant:
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return fn.call()
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func unwrap() -> Variant:
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assert(false, "Called unwrap() on a None value")
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return null
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