Pantograph/Pantograph/Tactic.lean

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import Lean
import Pantograph.Symbols
import Pantograph.Serial
/-
The proof state manipulation system
A proof state is launched by providing
1. Environment: `Environment`
2. Expression: `Expr`
The expression becomes the first meta variable in the saved tactic state
`Elab.Tactic.SavedState`.
From this point on, any proof which extends
`Elab.Term.Context` and
-/
def Lean.MessageLog.getErrorMessages (log : MessageLog) : MessageLog :=
{
msgs := log.msgs.filter fun m => match m.severity with | MessageSeverity.error => true | _ => false
}
namespace Pantograph
open Lean
structure ProofState where
goals : List MVarId
savedState : Elab.Tactic.SavedState
parent : Option Nat := none
parentGoalId : Nat := 0
structure ProofTree where
-- All parameters needed to run a `TermElabM` monad
name: Name
-- Set of proof states
states : Array ProofState := #[]
abbrev M := Elab.TermElabM
def ProofTree.create (name: Name) (expr: Expr): M ProofTree := do
let expr ← instantiateMVars expr
let goal := (← Meta.mkFreshExprMVar expr (kind := MetavarKind.synthetic))
let savedStateMonad: Elab.Tactic.TacticM Elab.Tactic.SavedState := MonadBacktrack.saveState
let savedState ← savedStateMonad { elaborator := .anonymous } |>.run' { goals := [goal.mvarId!]}
return {
name := name,
states := #[{
savedState := savedState,
goals := [goal.mvarId!]
}]
}
-- Print the tree structures in readable form
def ProofTree.structure_array (tree: ProofTree): Array String :=
tree.states.map λ state => match state.parent with
| .none => ""
| .some parent => s!"{parent}.{state.parentGoalId}"
def execute_tactic (state: Elab.Tactic.SavedState) (goal: MVarId) (tactic: String) :
M (Except (Array String) (Elab.Tactic.SavedState × List MVarId)):= do
let tacticM (stx: Syntax): Elab.Tactic.TacticM (Except (Array String) (Elab.Tactic.SavedState × List MVarId)) := do
state.restore
Elab.Tactic.setGoals [goal]
try
Elab.Tactic.evalTactic stx
if (← getThe Core.State).messages.hasErrors then
let messages := (← getThe Core.State).messages.getErrorMessages |>.toList.toArray
let errors ← (messages.map Message.data).mapM fun md => md.toString
return .error errors
else
return .ok (← MonadBacktrack.saveState, ← Elab.Tactic.getUnsolvedGoals)
catch exception =>
return .error #[← exception.toMessageData.toString]
match Parser.runParserCategory
(env := ← MonadEnv.getEnv)
(catName := `tactic)
(input := tactic)
(fileName := "<stdin>") with
| Except.error err => return .error #[err]
| Except.ok stx => tacticM stx { elaborator := .anonymous } |>.run' state.tactic
/-- Response for executing a tactic -/
inductive TacticResult where
-- Invalid id
| invalid (message: String): TacticResult
-- Goes to next state
| success (nextId?: Option Nat) (goals: Array Commands.Goal)
-- Fails with messages
| failure (messages: Array String)
/-- Execute tactic on given state -/
def ProofTree.execute (stateId: Nat) (goalId: Nat) (tactic: String):
Commands.OptionsT StateRefT ProofTree M TacticResult := do
let options ← read
let tree ← get
match tree.states.get? stateId with
| .none => return .invalid s!"Invalid state id {stateId}"
| .some state =>
match state.goals.get? goalId with
| .none => return .invalid s!"Invalid goal id {goalId}"
| .some goal =>
match (← execute_tactic (state := state.savedState) (goal := goal) (tactic := tactic)) with
| .error errors =>
return .failure errors
| .ok (nextState, nextGoals) =>
let nextId := tree.states.size
if nextGoals.isEmpty then
return .success .none #[]
else
let proofState: ProofState := {
savedState := nextState,
goals := nextGoals,
parent := stateId,
parentGoalId := goalId
}
modify fun s => { s with states := s.states.push proofState }
let parentDecl? := (← MonadMCtx.getMCtx).findDecl? goal
let goals ← nextGoals.mapM fun mvarId => do
match (← MonadMCtx.getMCtx).findDecl? mvarId with
| .some mvarDecl => serialize_goal options mvarDecl (parentDecl? := parentDecl?)
| .none => throwError mvarId
return .success (.some nextId) goals.toArray
end Pantograph