135 lines
4.3 KiB
Text
135 lines
4.3 KiB
Text
/-
|
||
Copyright (c) 2021 Microsoft Corporation. All rights reserved.
|
||
Released under Apache 2.0 license as described in the file LICENSE.
|
||
Authors: Sebastian Ullrich, Daniel Selsam, Wojciech Nawrocki
|
||
-/
|
||
import Lean.Meta.Basic
|
||
import Std.Data.RBMap
|
||
|
||
/-!
|
||
This file defines utilities for `MetaM` computations to traverse subexpressions
|
||
of an expression in sync with the `Nat` "position" values that refers to them.
|
||
We use a simple encoding scheme: every `Expr` constructor has at most 3 direct
|
||
expression children. Considering an expressions type as well, we can injectively
|
||
map a path of `childIdxs` to a natural number by computing the value of the 4-ary
|
||
representation `1 :: childIdxs`, since n-ary representations without leading zeros
|
||
are unique. Note that `pos` is initialized to `1` (case `childIdxs == []`).
|
||
-/
|
||
|
||
namespace Lean.PrettyPrinter.Delaborator
|
||
|
||
abbrev Pos := Nat
|
||
|
||
abbrev OptionsPerPos := Std.RBMap Pos Options compare
|
||
|
||
structure SubExpr where
|
||
expr : Expr
|
||
pos : Pos
|
||
|
||
namespace SubExpr
|
||
|
||
abbrev maxChildren : Pos := 4
|
||
|
||
variable {α : Type} [Inhabited α]
|
||
variable {m : Type → Type} [Monad m]
|
||
|
||
section Descend
|
||
|
||
variable [MonadReaderOf SubExpr m] [MonadWithReaderOf SubExpr m]
|
||
variable [MonadLiftT MetaM m] [MonadControlT MetaM m]
|
||
variable [MonadLiftT IO m]
|
||
|
||
def mkRoot (e : Expr) : SubExpr := ⟨e, 1⟩
|
||
|
||
def getExpr : m Expr := do (← readThe SubExpr).expr
|
||
def getPos : m Pos := do (← readThe SubExpr).pos
|
||
|
||
def descend (child : Expr) (childIdx : Pos) (x : m α) : m α :=
|
||
withTheReader SubExpr (fun cfg => { cfg with expr := child, pos := cfg.pos * maxChildren + childIdx }) x
|
||
|
||
def withAppFn (x : m α) : m α := do descend (← getExpr).appFn! 0 x
|
||
def withAppArg (x : m α) : m α := do descend (← getExpr).appArg! 1 x
|
||
|
||
def withType (x : m α) : m α := do
|
||
descend (← Meta.inferType (← getExpr)) (maxChildren - 1) x -- phantom positions for types
|
||
|
||
partial def withAppFnArgs (xf : m α) (xa : α → m α) : m α := do
|
||
if (← getExpr).isApp then
|
||
let acc ← withAppFn (withAppFnArgs xf xa)
|
||
withAppArg (xa acc)
|
||
else xf
|
||
|
||
def withBindingDomain (x : m α) : m α := do descend (← getExpr).bindingDomain! 0 x
|
||
|
||
def withBindingBody (n : Name) (x : m α) : m α := do
|
||
let e ← getExpr
|
||
Meta.withLocalDecl n e.binderInfo e.bindingDomain! fun fvar =>
|
||
descend (e.bindingBody!.instantiate1 fvar) 1 x
|
||
|
||
def withProj (x : m α) : m α := do
|
||
let Expr.proj _ _ e _ ← getExpr | unreachable!
|
||
descend e 0 x
|
||
|
||
def withMDataExpr (x : m α) : m α := do
|
||
let Expr.mdata _ e _ ← getExpr | unreachable!
|
||
withTheReader SubExpr (fun ctx => { ctx with expr := e }) x
|
||
|
||
def withLetVarType (x : m α) : m α := do
|
||
let Expr.letE _ t _ _ _ ← getExpr | unreachable!
|
||
descend t 0 x
|
||
|
||
def withLetValue (x : m α) : m α := do
|
||
let Expr.letE _ _ v _ _ ← getExpr | unreachable!
|
||
descend v 1 x
|
||
|
||
def withLetBody (x : m α) : m α := do
|
||
let Expr.letE n t v b _ ← getExpr | unreachable!
|
||
Meta.withLetDecl n t v fun fvar =>
|
||
let b := b.instantiate1 fvar
|
||
descend b 2 x
|
||
|
||
def withNaryFn (x : m α) : m α := do
|
||
let e ← getExpr
|
||
let n := e.getAppNumArgs
|
||
let newPos := (← getPos) * (maxChildren ^ n)
|
||
withTheReader SubExpr (fun cfg => { cfg with expr := e.getAppFn, pos := newPos }) x
|
||
|
||
def withNaryArg (argIdx : Nat) (x : m α) : m α := do
|
||
let e ← getExpr
|
||
let args := e.getAppArgs
|
||
let newPos := (← getPos) * (maxChildren ^ (args.size - argIdx)) + 1
|
||
withTheReader SubExpr (fun cfg => { cfg with expr := args[argIdx], pos := newPos }) x
|
||
|
||
end Descend
|
||
|
||
structure HoleIterator where
|
||
curr : Nat := 2
|
||
top : Nat := maxChildren
|
||
deriving Inhabited
|
||
|
||
section Hole
|
||
|
||
variable {α : Type} [Inhabited α]
|
||
variable {m : Type → Type} [Monad m]
|
||
variable [MonadStateOf HoleIterator m] [MonadWithReaderOf HoleIterator m]
|
||
|
||
def HoleIterator.toPos (iter : HoleIterator) : Pos :=
|
||
iter.curr
|
||
|
||
def HoleIterator.next (iter : HoleIterator) : HoleIterator :=
|
||
if (iter.curr+1) == iter.top then
|
||
⟨2*iter.top, maxChildren*iter.top⟩
|
||
else ⟨iter.curr+1, iter.top⟩
|
||
|
||
/-- The positioning scheme guarantees that there will be an infinite number of positions
|
||
that are never used by subexpressions. We use these to attach additional `Elab.Info`. -/
|
||
def nextExtraPos : m Pos := do
|
||
let iter ← getThe HoleIterator
|
||
let pos := iter.toPos
|
||
modifyThe HoleIterator HoleIterator.next
|
||
pos
|
||
|
||
end Hole
|
||
end SubExpr
|
||
|
||
end Lean.PrettyPrinter.Delaborator
|