005f6ae7cd
This PR fixes a bug in `Meta.zetaReduce` where `have` expressions were not being zeta reduced. It also adds a feature where applications of local functions are beta reduced, and another where zeta-delta reduction can be disabled. These are all controllable by flags: - `zetaDelta` (default: true) enables unfolding local definitions - `zetaHave` (default: true) enables zeta reducing `have` expressions - `beta` (default: true) enables beta reducing applications of local definitions Closes #10850
95 lines
1.8 KiB
Text
95 lines
1.8 KiB
Text
module
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public meta import Lean
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/-!
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# Testing `Lean.Meta.zetaReduce`
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It needs to be able to reduce both `let` and `have` expressions.
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Previously it was relying on the fact that `let` creates local definitions,
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then zeta-delta reducing.
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-/
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open Lean Elab Term Meta Tactic
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elab "zetaReduce " zd?:"zetaDelta"? zh?:"zetaHave"? beta?:"beta"? ":" t:term : tactic => withMainContext do
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let e ← elabTermAndSynthesize t none
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let e' ← zetaReduce e (zetaDelta := zd?.isSome) (zetaHave := zh?.isSome) (beta := beta?.isSome)
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logInfo m!"Before reduction:{indentExpr e}\nAfter reduction:{indentExpr e'}"
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/--
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info: Before reduction:
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(have m := 0 + 1;
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m - 1) =
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0
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After reduction:
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(have m := 0 + 1;
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m - 1) =
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0
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---
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info: Before reduction:
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(have m := 0 + 1;
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m - 1) =
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0
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After reduction:
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0 + 1 - 1 = 0
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---
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info: Before reduction:
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v
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After reduction:
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v
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---
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info: Before reduction:
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v
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After reduction:
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2
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---
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info: Before reduction:
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f v
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After reduction:
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f v
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---
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info: Before reduction:
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f v
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After reduction:
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(fun n =>
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have m := n;
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m + 1)
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2
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---
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info: Before reduction:
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f v
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After reduction:
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have m := 2;
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m + 1
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---
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info: Before reduction:
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f v
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After reduction:
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(fun n => n + 1) 2
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---
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info: Before reduction:
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f v
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After reduction:
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2 + 1
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---
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error: unsolved goals
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v : Nat := 2
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f : Nat → Nat :=
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fun n =>
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have m := n;
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let m' := m;
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m' + 1
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⊢ True
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-/
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#guard_msgs in
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example : True := by
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let v := 2
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let f n := have m := n; let m' := m; m' + 1
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zetaReduce : (have m := 0 + 1; m - 1) = 0
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zetaReduce zetaHave : (have m := 0 + 1; m - 1) = 0
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zetaReduce : v
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zetaReduce zetaDelta : v
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zetaReduce : f v
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zetaReduce zetaDelta : f v
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zetaReduce zetaDelta beta : f v
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zetaReduce zetaDelta zetaHave : f v
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zetaReduce zetaDelta zetaHave beta : f v
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