79 lines
1.3 KiB
V
79 lines
1.3 KiB
V
struct None {}
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// not named `Option` to avoid conflicts with the built-in type:
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type MyOption<T> = Error | None | T
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fn unwrap_if<T>(o MyOption<T>) T {
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if o is T {
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return o
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}
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panic('no value')
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}
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fn unwrap_match<T>(o MyOption<T>) string {
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match o {
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None {
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return 'none'
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}
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Error {
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return 'none'
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}
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T {
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return 'value'
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}
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}
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}
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fn test_generic_sumtype_unwrapping() {
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y := MyOption<bool>(false)
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assert unwrap_if(y) == false
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assert unwrap_match(y) == 'value'
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}
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fn test_generic_sumtype_auto_str() {
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x := MyOption<string>('hi')
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y := MyOption<bool>(None{})
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assert '$x, $y' == "MyOption<string>('hi'), MyOption<bool>(None{})"
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}
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struct Foo<T> {
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x T
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}
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struct Bar<T> {
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x T
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}
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type MyType<T> = Bar<T> | Foo<T>
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fn test_generic_struct_members() {
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// TODO: this is currently needed to properly resolve that variant's type:
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_ = Bar<string>{''}
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f := Foo<string>{'hi'}
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t := MyType<string>(f)
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assert t.type_name() == 'Foo<string>'
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// accessing a field common to all variants, just like with a normal sumtype:
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assert t.x == 'hi'
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}
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type MultiGeneric<X, Y, Z> = X | Y | Z
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fn test_multi_generic_type() {
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mut m := MultiGeneric<bool, int, string>(1234)
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m = 'hi'
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match m {
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bool {
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assert false
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}
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int {
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assert false
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}
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string {
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return
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}
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}
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assert false
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}
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