f4ebd38ce3
After this commit, `(+)` is notation for (add) instead of `(fun x y, add x y)`. This change is relevant when defining type class instances such as ```lean instance semigroup_to_is_associative [semigroup α] : is_associative α (*) := ⟨mul_assoc⟩ ```
32 lines
526 B
Text
32 lines
526 B
Text
open list
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#eval filter (< 10) [20, 5, 10, 3, 2, 14, 1]
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#eval qsort (λ x y, x < y) [20, 5, 10, 3, 2, 14, 1]
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#eval foldl (+) 0 [1, 2, 3]
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example : foldl (+) 0 [3, 4, 1] = 8 :=
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rfl
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example : foldl (*) 2 [3, 4, 1] = 24 :=
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rfl
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#check (+) 1 2
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example : (+) 1 2 = 3 :=
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rfl
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example : (*) 3 4 = 12 :=
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rfl
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example : (++) [1,2] [3,4] = [1,2,3,4] :=
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rfl
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example : (++) [1,2] [3,4] = [1,2] ++ [3,4] :=
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rfl
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/-
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(-) is rejected since we have prefix notation for -
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-/
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example : list.foldr (::) [] [1, 2, 3, 4] = [1, 2, 3, 4] :=
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rfl
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