5cef84709f
See Section "Other goodies" at https://github.com/leanprover/lean/wiki/Refactoring-structures This commit also improves the support for projections in the unifier/matcher. Now, we consider the extra case-split for projections. Given a projection `proj`, and the constraint `proj s =?= proj t`, we need to try first `s =?= t` and if it fails, then try to reduce. This is needed in the standard library because we now have constraints such as: ``` @has_le.le ?A ?s ?a ?b =?= @has_le.le nat nat.has_add x y ``` If we reduce the right hand side, we get the unsolvable constraint ``` @has_le.le ?A ?s ?a ?b =?= nat.le x y ``` Before this change, the constraint was `@le ?A ?s ?a ?b =?= @le nat nat.has_add x y`, and we already perform a case-split in this case. Moreover, projections were eagerly reduced whenever possible. The extra case-split generates a performance problem in several tests. For example `fib 8 = 34` was timing out. I worked around this issue by performing the case-split only when the constraint contains meta-variables. There are also minor issues. Example. `<` is notation for `has_lt.lt`, but `>` is for `gt`.
27 lines
383 B
Text
27 lines
383 B
Text
open nat
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#eval [1, 2, 3]
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#eval to_bool $ 1 ∈ [1, 2, 3]
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#eval to_bool $ 4 ∈ [1, 2, 3]
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#eval [1, 2, 3] ++ [3, 4]
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#eval 2 :: [3, 4]
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#eval ([] : list nat)
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#eval (∅ : list nat)
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#eval ({1, 3, 2, 2, 3, 1} : list nat)
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#eval [1, 2, 3] ∪ [3, 4, 1, 5]
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#eval [1, 2, 3] ∩ [3, 4, 1, 5]
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#eval (*10) <$> [1, 2, 3]
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#check ({1, 2, 3} : list nat)
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#check ({1, 2, 3, 4} : set nat)
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