lean4-htt/src/Lean/Meta/CollectMVars.lean
2020-08-27 14:59:54 -07:00

62 lines
1.8 KiB
Text

/-
Copyright (c) 2020 Microsoft Corporation. All rights reserved.
Released under Apache 2.0 license as described in the file LICENSE.
Authors: Leonardo de Moura
-/
import Lean.Util.CollectMVars
import Lean.Meta.Basic
namespace Lean
namespace Meta
/--
Collect unassigned metavariables occuring in the given expression.
Remark: if `e` contains `?m` and there is a `t` assigned to `?m`, we
collect unassigned metavariables occurring in `t`.
Remark: if `e` contains `?m` and `?m` is delayed assigned to some term `t`,
we collect `?m` and unassigned metavariables occurring in `t`.
We collect `?m` because it has not been assigned yet. -/
partial def collectMVarsAux : Expr → StateRefT CollectMVars.State MetaM Unit
| e => do
e ← instantiateMVars e;
s ← get;
let resultSavedSize := s.result.size;
let s := e.collectMVars s;
set s;
s.result.forFromM
(fun mvarId => do
d? ← getDelayedAssignment? mvarId;
match d? with
| none => pure ()
| some d => collectMVarsAux d.val)
resultSavedSize
def collectMVars (e : Expr) : StateRefT CollectMVars.State MetaM Unit :=
collectMVarsAux e
variables {m : Type → Type} [MonadLiftT MetaM m]
def getMVarsImp (e : Expr) : MetaM (Array MVarId) := do
(_, s) ← (collectMVars e).run {};
pure s.result
/-- Return metavariables in occuring the given expression. See `collectMVars` -/
def getMVars (e : Expr) : m (Array MVarId) :=
liftM $ getMVarsImp e
def collectMVarsAtDecl (d : Declaration) : StateRefT CollectMVars.State MetaM Unit :=
d.forExprM collectMVars
def getMVarsAtDeclImp (d : Declaration) : MetaM (Array MVarId) := do
(_, s) ← (collectMVarsAtDecl d).run {};
pure s.result
def getMVarsAtDecl (d : Declaration) : m (Array MVarId) :=
liftM $ getMVarsAtDeclImp d
end Meta
end Lean