Reason: vector in in init folder was introducing an overload (`::`) for
all Lean users. The workaround (use `local infix ::`) was
counterintuitive.
We currently have no special support for bitvectors in the code
generator. Thus, there is no need to have vector and bitvec in the init
folder right now. Moreover, the new parser and elaborator (issue #1674) should
provide better ways of managing overloaded symbols.
This gives a workaround for the situation where the `congr` tactic does too much congruence applications, such as reducing `|- a + b = b + a` to `|- a = b` and `|- b = a`, by supplying the desired equalities to stop at using `have`.
Now tactics supporting locations can also specify the goal among the locations by using the name `⊢` or `|-`. Also `rw at *` is implemented so that it will rewrite any hypotheses or the goal for which the whole sequence of rewrites succeeds. (This is different from `rw at h1 h2 ... hn |-`, which requires that all rewrites run to completion on each specified target.)
@digama0 I moved bitvec back to the main repo, and many nat lemmas.
I want these lemmas here for now. I will need some of them for future
decision procedures.
and all/any_goals. This occurs when solving the first subgoal generated by `tac1; tac2` closes the second goal as well, before the second `tac2` invocation is run. Reported by @jldodds on gitter.
This way people can search for "constant quot" and find it in the lean source. Plus the init_quotient command only occurs once, so this way people know what it means.
We need this feature for:
1) Defining nonlinear search patterns. Example: (?m <= ?m + 1)
2) Preprocessing recursive equations and support the pattern
refinement approach used in Agda. Example: in Agda, they accept
```
def append {A : Type} : Π (m n : nat), Vec A m -> Vec A n -> Vec A (m + n)
| m n nil ys := ys
| m n (cons m' x xs) ys := cons x (append m' n xs ys)
```
These equations have to be refined. For example, `m` has to be
replaced with `0` (in the first equation), and `succ m'` in the
second. To implement this kind of refinement, we need to convert
the pattern variables (local constants) into metavariables during
elaboration. Then, the unassigned metavariables become local constants
again. This preprocessing step will fix some of the issues on #1594.
To completely fix#1594, we will need yet another preprocessing step
which will implement "complete transition" used in the equation
compiler before we start elim_match.cpp
