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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.)
43 lines
1.9 KiB
Text
43 lines
1.9 KiB
Text
/-
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Copyright (c) 2016 Microsoft Corporation. All rights reserved.
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Released under Apache 2.0 license as described in the file LICENSE.
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Authors: Leonardo de Moura
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-/
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prelude
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import init.meta.relation_tactics init.meta.occurrences
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namespace tactic
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/-- Configuration options for the `rewrite` tactic. -/
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structure rewrite_cfg extends apply_cfg :=
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(md := reducible)
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(symm := ff)
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(occs := occurrences.all)
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/-- Rewrite the expression `e` using `h`.
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The unification is performed using the transparency mode in `cfg`.
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If `cfg.approx` is `tt`, then fallback to first-order unification, and approximate context during unification.
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`cfg.new_goals` specifies which unassigned metavariables become new goals, and their order.
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If `cfg.instances` is `tt`, then use type class resolution to instantiate unassigned meta-variables.
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The fields `cfg.auto_param` and `cfg.opt_param` are ignored by this tactic (See `tactic.rewrite`).
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It a triple `(new_e, prf, metas)` where `prf : e = new_e`, and `metas` is a list of all introduced meta variables,
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even the assigned ones.
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TODO(Leo): improve documentation and explain symm/occs -/
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meta constant rewrite_core (h : expr) (e : expr) (cfg : rewrite_cfg := {}) : tactic (expr × expr × list expr)
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meta def rewrite (h : expr) (e : expr) (cfg : rewrite_cfg := {}) : tactic (expr × expr × list expr) :=
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do (new_t, prf, metas) ← rewrite_core h e cfg,
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try_apply_opt_auto_param cfg.to_apply_cfg metas,
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return (new_t, prf, metas)
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meta def rewrite_target (h : expr) (cfg : rewrite_cfg := {}) : tactic unit :=
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do t ← target,
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(new_t, prf, _) ← rewrite h t cfg,
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replace_target new_t prf
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meta def rewrite_hyp (h : expr) (hyp : expr) (cfg : rewrite_cfg := {}) : tactic expr :=
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do hyp_type ← infer_type hyp,
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(new_hyp_type, prf, _) ← rewrite h hyp_type cfg,
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replace_hyp hyp new_hyp_type prf
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end tactic
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