57 lines
1.5 KiB
Text
57 lines
1.5 KiB
Text
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--| Apply a function across the values of a `Map k v`, dropping
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-- entries whose values return `None`.
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let Map/empty =
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missing
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sha256:4c612558b8bbe8f955550ed3fb295d57b1b864c85cd52615b52d0ee0e9682e52
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? ./empty.dhall
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let Map/unpackOptionals =
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missing
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sha256:66c3e6f6f81418cf99342e1dba739617c01af4b27c1ca5e2e1d7bce64a522e22
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? ./unpackOptionals.dhall
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let Map/map =
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missing
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sha256:23e09b0b9f08649797dfe1ca39755d5e1c7cad2d0944bdd36c7a0bf804bde8d0
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? ./map.dhall
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let Map/Type =
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missing
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sha256:210c7a9eba71efbb0f7a66b3dcf8b9d3976ffc2bc0e907aadfb6aa29c333e8ed
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? ./Type.dhall
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let mapMaybe
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: ∀(k : Type) →
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∀(a : Type) →
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∀(b : Type) →
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(a → Optional b) →
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Map/Type k a →
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Map/Type k b
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= λ(k : Type) →
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λ(a : Type) →
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λ(b : Type) →
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λ(f : a → Optional b) →
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λ(m : Map/Type k a) →
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Map/unpackOptionals k b (Map/map k a (Optional b) f m)
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let property =
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λ(k : Type) →
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λ(a : Type) →
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λ(b : Type) →
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λ(f : a → Optional b) →
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assert : mapMaybe k a b f (Map/empty k a) ≡ Map/empty k b
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let example0 =
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assert
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: mapMaybe
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Text
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Natural
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Text
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( λ(n : Natural) →
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if Natural/isZero n then None Text else Some (Natural/show n)
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)
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(toMap { foo = 2, bar = 0 })
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≡ toMap { foo = "2" }
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in mapMaybe
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