1ce7047bf5
This PR moves away from using `List.get` / `List.get?` / `List.get!` and `Array.get!`, in favour of using the `GetElem` mediated getters. In particular it deprecates `List.get?`, `List.get!` and `Array.get?`. Also adds `Array.back`, taking a proof, matching `List.getLast`.
66 lines
1.6 KiB
Text
66 lines
1.6 KiB
Text
import Lean
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open Lean
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open Lean.Meta
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inductive Vec (α : Type) : Nat → Type
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| nil : Vec α 0
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| cons {n} : α → Vec α n → Vec α (n+1)
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set_option trace.Meta.debug true
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def nat := mkConst `Nat
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def succ := mkConst `Nat.succ
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def tst1 : MetaM Unit :=
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withLocalDeclD `n nat fun n => do
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let n1 := mkApp succ n
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let vecN1 := mkApp2 (mkConst `Vec) nat n1
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withLocalDeclD `xs vecN1 fun xs => do
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generalizeTelescope #[n1, xs] fun ys => do
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let t ← mkLambdaFVars ys ys.back!
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trace[Meta.debug] t
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pure ()
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/-- info: [Meta.debug] fun x x => x -/
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#guard_msgs in
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#eval tst1
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set_option pp.all true
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def tst2 : MetaM Unit :=
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withLocalDeclD `n nat fun n => do
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let n1 := mkApp succ n
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let vecN1 := mkApp2 (mkConst `Vec) nat n1
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withLocalDeclD `xs vecN1 $ fun xs => do
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let e ← mkEqRefl xs
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generalizeTelescope #[n1, xs, e] fun ys => do
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let t ← mkLambdaFVars ys ys.back!
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trace[Meta.debug] t
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pure ()
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/-- info: [Meta.debug] fun (x : Nat) (x_1 : Vec Nat x) (x : @Eq.{1} (Vec Nat x) x_1 x_1) => x -/
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#guard_msgs in
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#eval tst2
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def failIfSuccess (x : MetaM Unit) : MetaM Unit := do
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let worked ← try x; pure true catch _ => pure false
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if worked then
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throwError "unexpected success"
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def tst3 : MetaM Unit :=
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withLocalDeclD `n nat $ fun n => do
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let n1 := mkApp succ n
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let vecN1 := mkApp2 (mkConst `Vec) nat n1
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withLocalDeclD `xs vecN1 $ fun xs => do
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let e ← mkEqRefl xs
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failIfSuccess do
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generalizeTelescope #[n1, e] fun ys => do
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let t ← mkLambdaFVars ys ys.back!
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trace[Meta.debug] t
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pure ()
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trace[Meta.debug] "failed as expected"
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/-- info: [Meta.debug] failed as expected -/
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#guard_msgs in
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#eval tst3
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