36 lines
No EOL
1,013 B
Text
36 lines
No EOL
1,013 B
Text
Variable list : Type -> Type
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Variable nil {A : Type} : list A
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Variable cons {A : Type} (head : A) (tail : list A) : list A
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Definition n1 : list Int := cons (nat_to_int 10) nil
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Definition n2 : list Nat := cons 10 nil
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(*
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The following example demonstrates that the expected type (list Int)
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does not influece whether coercions are used or not.
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*)
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Definition n3 : list Int := cons 10 nil
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(*
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Here are some workarounds for the example above.
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The 'let' construct is one of the main tools for providing
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hints.
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*)
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Definition n3a : list Int :=
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let a : Int := 10
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in cons a nil
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(* Solution b: we manually provide the coercion *)
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Definition n3b : list Int := cons (nat_to_int 10) nil
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(* The folowing example works *)
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Definition n4 : list Int := nil
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(*
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The following example demonstrates that we do not do type inference.
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In the current implementation, we first elaborate the type and
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then the body.
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*)
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Definition n5 : _ := cons 10 nil
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Set pp::coercion true
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Set pp::implicit true
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Show Environment 1. |