dc001a01e5
This PR adds the `binderNameHint` gadget. It can be used in rewrite and
simp rules to preserve a user-provided name where possible.
The expression `binderNameHint v binder e` defined to be `e`.
If it is used on the right-hand side of an equation that is applied by a
tactic like `rw` or `simp`,
and `v` is a local variable, and `binder` is an expression that (after
beta-reduction) is a binder
(so `fun w => …` or `∀ w, …`), then it will rename `v` to the name used
in the binder, and remove
the `binderNameHint`.
A typical use of this gadget would be as follows; the gadget ensures
that after rewriting, the local
variable is still `name`, and not `x`:
```
theorem all_eq_not_any_not (l : List α) (p : α → Bool) :
l.all p = !l.any fun x => binderNameHint x p (!p x) := sorry
example (names : List String) : names.all (fun name => "Waldo".isPrefixOf name) = true := by
rw [all_eq_not_any_not]
-- ⊢ (!names.any fun name => !"Waldo".isPrefixOf name) = true
```
This gadget is supported by `simp`, `dsimp` and `rw` in the
right-hand-side of an equation, but not
in hypotheses or by other tactics.
54 lines
1.5 KiB
Text
54 lines
1.5 KiB
Text
/-
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Copyright (c) 2019 Microsoft Corporation. All rights reserved.
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Released under Apache 2.0 license as described in the file LICENSE.
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Authors: Leonardo de Moura
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-/
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prelude
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import Lean.Meta.Basic
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import Lean.Meta.LevelDefEq
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import Lean.Meta.WHNF
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import Lean.Meta.InferType
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import Lean.Meta.FunInfo
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import Lean.Meta.ExprDefEq
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import Lean.Meta.DecLevel
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import Lean.Meta.DiscrTree
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import Lean.Meta.Reduce
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import Lean.Meta.Instances
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import Lean.Meta.AbstractMVars
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import Lean.Meta.SynthInstance
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import Lean.Meta.AppBuilder
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import Lean.Meta.Sorry
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import Lean.Meta.Tactic
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import Lean.Meta.KAbstract
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import Lean.Meta.RecursorInfo
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import Lean.Meta.GeneralizeTelescope
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import Lean.Meta.Match
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import Lean.Meta.ReduceEval
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import Lean.Meta.Closure
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import Lean.Meta.AbstractNestedProofs
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import Lean.Meta.ForEachExpr
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import Lean.Meta.Transform
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import Lean.Meta.PPGoal
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import Lean.Meta.UnificationHint
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import Lean.Meta.Inductive
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import Lean.Meta.SizeOf
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import Lean.Meta.IndPredBelow
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import Lean.Meta.Coe
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import Lean.Meta.CollectFVars
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import Lean.Meta.GeneralizeVars
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import Lean.Meta.Injective
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import Lean.Meta.Structure
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import Lean.Meta.Constructions
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import Lean.Meta.CongrTheorems
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import Lean.Meta.Eqns
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import Lean.Meta.ExprLens
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import Lean.Meta.ExprTraverse
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import Lean.Meta.Eval
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import Lean.Meta.CoeAttr
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import Lean.Meta.Iterator
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import Lean.Meta.LazyDiscrTree
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import Lean.Meta.LitValues
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import Lean.Meta.CheckTactic
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import Lean.Meta.Canonicalizer
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import Lean.Meta.Diagnostics
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import Lean.Meta.BinderNameHint
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