This PR adds a new helper parser for implementing parsers that contain
hexadecimal numbers. We are going to use it to implement anchors in the
`grind` interactive mode.
This PR aims to fix the Timer API selector to make it finish as soon as
possible when unregistered. This change makes the `Selectable.one`
function drop the `selectables` array as soon as possible, so when
combined with finalizers that have some effects like the TCP socket
finalizer, it runs it as soon as possible.
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 introduces a `coinductive` keyword, that can be used to define
coinductive predicates via a syntax identical to the one for `inductive`
keyword. The machinery relies on the implementation of elaboration of
inductive types and extracts an endomap on the appropriate space of the
predicates from the definition that is then fed to the
`PartialFixpoint`. Upon elaborating definitions, all the constructors
are declared through automatically generated lemmas.
For example, infinite sequence of transitions in a relation, can be
given by the following:
```lean4
section
variable (α : Type)
coinductive infSeq (r : α → α → Prop) : α → Prop where
| step : r a b → infSeq r b → infSeq r a
/--
info: infSeq.coinduct (α : Type) (r : α → α → Prop) (pred : α → Prop) (hyp : ∀ (x : α), pred x → ∃ b, r x b ∧ pred b)
(x✝ : α) : pred x✝ → infSeq α r x✝
-/
#guard_msgs in
#check infSeq.coinduct
/--
info: infSeq.step (α : Type) (r : α → α → Prop) {a b : α} : r a b → infSeq α r b → infSeq α r a
-/
#guard_msgs in
#check infSeq.step
end
```
The machinery also supports `mutual` blocks, as well as mixing inductive
and coinductive predicate definitions:
```lean4
mutual
coinductive tick : Prop where
| mk : ¬tock → tick
inductive tock : Prop where
| mk : ¬tick → tock
end
/--
info: tick.mutual_induct (pred_1 pred_2 : Prop) (hyp_1 : pred_1 → pred_2 → False) (hyp_2 : (pred_1 → False) → pred_2) :
(pred_1 → tick) ∧ (tock → pred_2)
-/
#guard_msgs in
#check tick.mutual_induct
```
---------
Co-authored-by: Joachim Breitner <mail@joachim-breitner.de>
This PR changes how Lean proves the equational theorems for structural
recursion. The core idea is to let-bind the `f` argument to `brecOn` and
rewriting `.brecOn` with an unfolding theorem. This means no extra case
split for the `.rec` in `.brecOn` is needed, and `simp` doesn't change
the `f` argument which can break the definitional equality with the
defined function. With this, we can prove the unfolding theorem first,
and derive the equational theorems from that, like for all other ways of
defining recursive functions.
Backs out the changes from #10415, the old strategy works well with the
new goals.
Fixes#5667Fixes#10431Fixes#10195Fixes#2962
This PR adds the StreamMap type that enables multiplexing in
asynchronous streams.
This PR depends on: #10366, #10367 and #10370.
---------
Co-authored-by: Markus Himmel <markus@lean-fro.org>
This PR adds the `IO.FS.hardLink` function, which can be used to create
hard links.
This is implemented via libuv's `uv_fs_link` function.
Lake hopes to make use of this function to decrease the storage cost of
restoring artifacts.
This PR also fixes some C implementation issues found in nearby similar
functions.
This PR adds a multi-consumer, multi-producer channel to Std.Sync.
This PR depends on: #10366, #10367 and #10370.
---------
Co-authored-by: Markus Himmel <markus@lean-fro.org>
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
```
This PR records extra mod uses that previously caused wrong unnecessary
import reports from shake.
---------
Co-authored-by: Sebastian Ullrich <sebasti@nullri.ch>
This PR "monomorphizes" the structure `Std.PRange shape α`, replacing it
with nine distinct structures `Std.Rcc`, `Std.Rco`, `Std.Rci` etc., one
for each possible shape of a range's bounds. This change was necessary
because the shape polymorphism is detrimental to attempts of automation.
**BREAKING CHANGE:** While range/slice notation itself is unchanged,
this essentially breaks the entire remaining (polymorphic) range and
slice API except for the dot-notation(`toList`, `iter`, ...). It is not
possible to deprecate old declarations that were formulated in a
shape-polymorphic way that is not available anymore.
This PR explicitly tries to synthesize synthetic MVars in `mspec`. Doing
so resolves a bug triggered by use of the loop invariant lemma for
`Std.PRange`.
This PR exposes the definitions about `Int*`. The main reason is that
the `SInt` simprocs require many of them to be exposed. Furthermore,
`decide` now works with `Int*` operations. This fixes#10631.
This PR defines `ByteArray.validateUTF8`, uses it to show that
`ByteArray.IsValidUtf8` is decidable and redefines `String.fromUTF8` and
friends to use it.
The functions `String.validateUTF8` and `String.utf8DecodeChar?` are
deprecated in favor of the identically named functions in the
`ByteArray` namespace.
This PR removes superfluous `Monad` instances from the spec lemmas of
the `MonadExceptOf` lifting framework.
It also adds a bit of documentation and more tracing to `mvcgen`.
Fixes#10564.
This PR ensures that even if a type is marked as `irreducible` the
compiler can see through it in
order to discover functions hidden behind type aliases.
This PR adds the necessary infrastructure for recording elaboration
dependencies that may not be apparent from the resulting environment
such as notations and other metaprograms. An adapted version of `shake`
from Mathlib is added to `script/` but may be moved to another location
or repo in the future.
This PR implements support for negative constraints in `grind order`.
Examples:
```lean
open Lean Grind
example [LE α] [LT α] [Std.LawfulOrderLT α] [Std.IsLinearPreorder α]
(a b c d : α) : a ≤ b → ¬ (c ≤ b) → ¬ (d ≤ c) → d < a → False := by
grind -linarith (splits := 0)
example [LE α] [Std.IsLinearPreorder α]
(a b c d : α) : a ≤ b → ¬ (c ≤ b) → ¬ (d ≤ c) → ¬ (a ≤ d) → False := by
grind -linarith (splits := 0)
example [LE α] [LT α] [Std.LawfulOrderLT α] [Std.IsLinearPreorder α] [CommRing α] [OrderedRing α]
(a b c d : α) : a - b ≤ 5 → ¬ (c ≤ b) → ¬ (d ≤ c + 2) → d ≤ a - 8 → False := by
grind -linarith (splits := 0)
```
This PR implements support for positive constraints in `grind order`.
The new module can already solve problems such as:
```lean
example [LE α] [LT α] [Std.LawfulOrderLT α] [Std.IsPreorder α]
(a b c : α) : a ≤ b → b ≤ c → c < a → False := by
grind
example [LE α] [LT α] [Std.LawfulOrderLT α] [Std.IsPreorder α]
(a b c d : α) : a ≤ b → b ≤ c → c < d → d ≤ a → False := by
grind
example [LE α] [Std.IsPreorder α]
(a b c : α) : a ≤ b → b ≤ c → a ≤ c := by
grind
example [LE α] [Std.IsPreorder α]
(a b c d : α) : a ≤ b → b ≤ c → c ≤ d → a ≤ d := by
grind
```
It also generalizes support for offset constraints in `grind` to rings.
The new module implements theory propagation and reduces the number of
case splits required to solve problems:
```lean
example [LE α] [LT α] [Std.LawfulOrderLT α] [Std.IsPreorder α] [Ring α] [OrderedRing α]
(a b : α) : a ≤ 5 → b ≤ 8 → a > 6 ∨ b > 10 → False := by
grind -linarith (splits := 0)
example [LE α] [LT α] [Std.LawfulOrderLT α] [Std.IsPreorder α] [CommRing α] [OrderedRing α]
(a b c : α) : a + b*c + 2*c ≤ 5 → a + c > 5 - c - c*b → False := by
grind -linarith (splits := 0)
example (a b : Int) (h : a + b > 5) : (if a + b ≤ 0 then b else a) = a := by
grind -linarith -cutsat (splits := 0)
```
We still need to implement support for negated constraints.
This PR ensures that `SPred` proof mode tactics such as `mspec`,
`mintro`, etc. immediately replace the main goal when entering the proof
mode. This prevents `No goals to be solved` errors.
This PR adds support for case label like syntax in `mvcgen invariants`
in order to refer to inaccessible names. Example:
```lean
def copy (l : List Nat) : Id (Array Nat) := do
let mut acc := #[]
for x in l do
acc := acc.push x
return acc
theorem copy_labelled_invariants (l : List Nat) : ⦃⌜True⌝⦄ copy l ⦃⇓ r => ⌜r = l.toArray⌝⦄ := by
mvcgen [copy] invariants
| inv1 acc => ⇓ ⟨xs, letMuts⟩ => ⌜acc = l.toArray⌝
with admit
```
This PR improves `mvcgen invariants?` to suggest concrete invariants
based on how invariants are used in VCs.
These suggestions are intentionally simplistic and boil down to "this
holds at the start of the loop and this must hold at the end of the
loop":
```lean
def mySum (l : List Nat) : Nat := Id.run do
let mut acc := 0
for x in l do
acc := acc + x
return acc
/--
info: Try this:
invariants
· ⇓⟨xs, letMuts⟩ => ⌜xs.prefix = [] ∧ letMuts = 0 ∨ xs.suffix = [] ∧ letMuts = l.sum⌝
-/
#guard_msgs (info) in
theorem mySum_suggest_invariant (l : List Nat) : mySum l = l.sum := by
generalize h : mySum l = r
apply Id.of_wp_run_eq h
mvcgen invariants?
all_goals admit
```
It still is the user's job to weaken this invariant such that it
interpolates over all loop iterations, but it *is* a good starting point
for iterating. It is also useful because the user does not need to
remember the exact syntax.
This PR simplifies the `grind order` module, and internalizes the order
constraints. It removes the `Offset` type class because it introduced
too much complexity. We now cover the same use cases with a simpler
approach:
- Any type that implements at least `Std.IsPreorder`
- Arbitrary ordered rings.
- `Nat` by the `Nat.ToInt` adapter.
This PR changes the way that scientific numerals are parsed in order to
give better error messages for (invalid) syntax like `32.succ`.
Example:
```lean4
#check 32.succ
```
Before, the error message is:
```
unexpected identifier; expected command
```
This is because `32.` parses as a complete float, and `#check 32.`
parses as a complete command, so `succ` is being read as the start of a
new command.
With this change, the error message will move from the `succ` token to
the `32` token (which isn't totally ideal from my perspective) but gives
a less misleading error message and corresponding suggestion:
```
unexpected identifier after decimal point; consider parenthesizing the number
```
