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.
This PR adds the `try?` tactic. This is the first draft, but it can
already solve examples such as:
```lean
example (e : Expr) : e.simplify.eval σ = e.eval σ := by
try?
```
in `grind_constProp.lean`. In the example above, it suggests:
```lean
induction e using Expr.simplify.induct <;> grind?
```
In the same test file, we have
```lean
example (σ₁ σ₂ : State) : σ₁.join σ₂ ≼ σ₂ := by
try?
```
and the following suggestion is produced
```lean
induction σ₁, σ₂ using State.join.induct <;> grind?
```
This PR changes the signature of `Array.set` to take a `Nat`, and a
tactic-provided bound, rather than a `Fin`.
Corresponding changes (but without the auto-param) for `Array.get` will
arrive shortly, after which I'll go more pervasively through the Array
API.
[Before](https://github.com/leanprover/lean4/files/14772220/oi.pdf) and
[after](https://github.com/leanprover/lean4/files/14772226/oi2.pdf).
This gets `ByteArray`, `String.Extra`, `ToString.Macro` and `RCases` out
of the imports of `omega`. I'd hoped to get `Array.Subarray` too, but
it's tangled up in the list literal syntax. Further progress could come
from make `split` use available `Decidable` instances, so we could pull
out `Classical` (and possibly some of `PropLemmas`).
This is not a complete upstreaming of that file (it also supports `∀ᵉ (x
< 2) (y < 3), p x y` as shorthand for `∀ x < 2, ∀ y < 3, p x y`, but I
don't think we need this; it is used in Mathlib).
Syntaxes still need to be made built-in.
---------
Co-authored-by: Leonardo de Moura <leomoura@amazon.com>
This will collect definitions from Std.Logic
---------
Co-authored-by: David Thrane Christiansen <david@davidchristiansen.dk>
Co-authored-by: Scott Morrison <scott.morrison@gmail.com>
This moves the `rcases` and `obtain` tactics from Std, and makes them
built-in tactics.
We will separately move the test cases from Std after #3297
(`guard_expr`).
---------
Co-authored-by: Leonardo de Moura <leomoura@amazon.com>
Allow `simproc`s to be declared without setting the `[simproc]`
attribute. A `simproc` declaration is function + pattern.
Motivation: allow them to be provided as arguments to `simp` **and** `simp only`.
TODO: track their use in `simp`.
TODO: builtin simprocs
