This PR ensures `grind` can use constructors and axioms for heuristic
instantiation based on E-matching. It also allows patterns without
pattern variables for theorems such as `theorem evenz : Even 0`.
This PR introduces the parametric attribute `[grind]` for annotating
theorems and definitions. It also replaces `[grind_eq]` with `[grind
=]`. For definitions, `[grind]` is equivalent to `[grind =]`.
The new attribute supports the following variants:
- **`[grind =]`**: Uses the left-hand side of the theorem's conclusion
as the pattern for E-matching.
- **`[grind =_]`**: Uses the right-hand side of the theorem's conclusion
as the pattern for E-matching.
- **`[grind _=_]`**: Creates two patterns. One for the left-hand side
and one for the right-hand side.
- **`[grind →]`**: Searches for (multi-)patterns in the theorem's
antecedents, stopping once a usable multi-pattern is found.
- **`[grind ←]`**: Searches for (multi-)patterns in the theorem's
conclusion, stopping once a usable multi-pattern is found.
- **`[grind]`**: Searches for (multi-)patterns in both the theorem's
conclusion and antecedents. It starts with the conclusion and stops once
a usable multi-pattern is found.
The `grind_pattern` command remains available for cases where these
attributes do not yield the desired result.
This PR introduces the `[grind_eq]` attribute, designed to annotate
equational theorems and functions for heuristic instantiations in the
`grind` tactic.
When applied to an equational theorem, the `[grind_eq]` attribute
instructs the `grind` tactic to automatically use the annotated theorem
to instantiate patterns during proof search. If applied to a function,
it marks all equational theorems associated with that function.
```lean
@[grind_eq]
theorem foo_idempotent : foo (foo x) = foo x := ...
@[grind_eq] def f (a : Nat) :=
match a with
| 0 => 10
| x+1 => g (f x)
```
In the example above, the `grind` tactic will add instances of the
theorem `foo_idempotent` to the local context whenever it encounters the
pattern `foo (foo x)`. Similarly, functions annotated with `[grind_eq]`
will propagate this annotation to their associated equational theorems.
This PR adds pattern validation to the `grind_pattern` command. The new
`checkCoverage` function will also be used to implement the attributes
`@[grind_eq]`, `@[grind_fwd]`, and `@[grind_bwd]`.
This PR implements the command `grind_pattern`. The new command allows
users to associate patterns with theorems. These patterns are used for
performing heuristic instantiation with e-matching. In the future, we
will add the attributes `@[grind_eq]`, `@[grind_fwd]`, and
`@[grind_bwd]` to compute the patterns automatically for theorems.
