This PR implements the `have <ident>? : <prop>` tactic for the `grind`
interactive mode. The proposition is proved using the default `grind`
search strategy. This tactic is also useful for inspecting or querying
the current `grind` state.
This PR improves the `grind` tactic generated by the `instantiate`
action in tracing mode. It also updates the syntax for the `instantiate`
tactic, making it similar to `simp`. For example:
* `instantiate only [thm1, thm2]` instantiates only theorems `thm1` and
`thm2`.
* `instantiate [thm1, thm2]` instantiates theorems marked with the
`@[grind]` attribute **and** theorems `thm1` and `thm2`.
The action produces `instantiate only [...]` tactics. Example:
```lean
/--
info: Try this:
[apply] ⏎
instantiate only [= Array.getElem_set]
instantiate only [= Array.getElem_set]
-/
#guard_msgs in
example (as bs cs : Array α) (v₁ v₂ : α)
(i₁ i₂ j : Nat)
(h₁ : i₁ < as.size)
(h₂ : bs = as.set i₁ v₁)
(h₃ : i₂ < bs.size)
(h₄ : cs = bs.set i₂ v₂)
(h₅ : i₁ ≠ j ∧ i₂ ≠ j)
(h₆ : j < cs.size)
(h₇ : j < as.size) :
cs[j] = as[j] := by
grind => finish?
```
Recall that `finish?` replays generated tactics before suggesting them.
The `instantiate` action inspects the generated proof term to decide
which theorems to include as parameters in the `instantiate only [...]`
tactic. However, in some cases, a theorem contributes only by adding a
term to the state. In such cases, the generated tactic cannot be fully
replayed, and the action uses
`instantiate approx [<thms instantiated>]` to indicate which parts of
the tactic script are approximate. The `approx` is just a hint for
users.
This PR implements a compact notation for inspecting the `grind` state
in interactive mode. Within a `grind` tactic block, each tactic may
optionally have a suffix of the form `| filter?`.
Examples:
```lean
instantiate | gen > 0 -- Displays terms in the `grind` state after executing `instantiate` with generation greater than zero
```
```lean
instantiate | -- Displays the `grind` state after executing `instantiate`
```
Remark: If the user places the cursor one space before `|`, the state
*before* executing `instantiate` is displayed.
This PR removes the code that was silently displaying the `grind` state
after each tactic step, as it was too noisy.
It also updates the notation for the `first` combinator in the `grind`
tactic mode to avoid conflicts with the new syntax.
This PR ensures that `grind` interactive mode is hygienic. It also adds
tactics for renaming inaccessible names: `rename_i h_1 ... h_n` and
`next h_1 ... h_n => ..`, and `expose_names` for automatically generated
tactic scripts. The PR also adds helper functions for implementing
case-split actions.
This PR improves the tactics `ac`, `linarith`, `lia`, `ring` tactics in
`grind` interactive mode. They now fail if no progress has been made.
They also generate an info message with counterexample/basis if the goal
was not closed.
This PR adds the following tactics to the `grind` interactive mode:
- `focus <grind_tac_seq>`
- `next => <grind_tac_seq>`
- `any_goals <grind_tac_seq>`
- `all_goals <grind_tac_seq>`
- `grind_tac <;> grind_tac`
- `cases <anchor>`
- `tactic => <tac_seq>`
Example:
```lean
def g (as : List Nat) :=
match as with
| [] => 1
| [_] => 2
| _::_::_ => 3
example : g bs = 1 → g as ≠ 0 := by
grind [g.eq_def] =>
instantiate
cases #ec88
next => instantiate
next => finish
tactic =>
rw [h_2] at h_1
simp [g] at h_1
```
This PR implements *anchors* (also known as stable hash codes) for
referencing terms occurring in a `grind` goal. It also introduces the
commands `show_splits` and `show_state`. The former displays the anchors
for candidate case splits in the current `grind` goal.
This PR adds the `have` tactic for the `grind` interactive mode.
Example:
```lean
example {a b c d e : Nat}
: a > 0 → b > 0 → 2*c + e <= 2 → e = d + 1 → a*b + 2 > 2*c + d := by
grind =>
have : a*b > 0 := Nat.mul_pos h h_1
lia
```
This PR implements the basic tactics for the new `grind` interactive
mode. While many additional `grind` tactics will be added later, the
foundational framework is already operational. The following `grind`
tactics are currently implemented: `skip`, `done`, `finish`, `lia`, and
`ring`.
This PR also removes the notion of `grind` fallback procedure since it
is subsumed by the new framework. Examples:
```lean
example (x y : Nat) : x ≥ y + 1 → x > 0 := by
grind => skip; lia; done
open Lean Grind
example [CommRing α] (a b c : α)
: a + b + c = 3 →
a^2 + b^2 + c^2 = 5 →
a^3 + b^3 + c^3 = 7 →
a^4 + b^4 + c^4 = 9 := by
grind => ring
```
