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`.
16 lines
313 B
Text
16 lines
313 B
Text
open tactic list
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meta definition foo (a : pexpr) : pexpr :=
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`(%%a + %%a + %%a + b)
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example (a b : nat) : a = a :=
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by do
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a ← get_local `a,
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t1 ← mk_app ``has_add.add [a, a],
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t2 ← to_expr (foo (to_pexpr t1)),
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trace t2,
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r ← mk_app (`eq.refl) [a],
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exact r
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private def f := unit
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#check ``f
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