feat: Add REPL function for root expression

Pantograph.lean

@@ -39,6 +39,7 @@ def execute (command: Protocol.Command): MainM Lean.Json := do
   | "goal.start"     => run goal_start
   | "goal.tactic"    => run goal_tactic
   | "goal.delete"    => run goal_delete
+  | "goal.print"    => run goal_print
   | cmd =>
     let error: Protocol.InteractionError :=
       errorCommand s!"Unknown command {cmd}"
@@ -174,5 +175,14 @@ def execute (command: Protocol.Command): MainM Lean.Json := do
     let goalStates := args.stateIds.foldl (λ map id => map.remove id) state.goalStates
     set { state with goalStates }
     return .ok {}
+  goal_print (args: Protocol.GoalPrint): MainM (CR Protocol.GoalPrintResult) := do
+    let state ← get
+    match state.goalStates.get? args.stateId with
+    | .none => return .error $ errorIndex s!"Invalid state index {args.stateId}"
+    | .some goalState => do
+      let root? ← goalState.rootExpr?.mapM (λ expr => serialize_expression state.options expr)
+      return .ok {
+        root?,
+      }
 
 end Pantograph

Pantograph/Goal.lean

@@ -190,7 +190,7 @@ protected def GoalState.continue (target: GoalState) (graftee: GoalState): Excep
       newMVars := graftee.newMVars,
     }
 
-protected def GoalState.rootExpr (goalState: GoalState): Option Expr :=
+protected def GoalState.rootExpr? (goalState: GoalState): Option Expr :=
   let expr := goalState.mctx.eAssignment.find! goalState.root
   let (expr, _) := instantiateMVarsCore (mctx := goalState.mctx) (e := expr)
   if expr.hasMVar then

Pantograph/Protocol.lean

@@ -171,6 +171,15 @@ structure GoalDeleteResult where
   deriving Lean.ToJson
 
 structure GoalPrint where
+  stateId: Nat
+  deriving Lean.FromJson
+structure GoalPrintResult where
+  -- The root expression
+  root?: Option Expression
+  deriving Lean.ToJson
+
+-- Diagnostic Options, not available in REPL
+structure GoalDiag where
   printContext: Bool := true
   printValue: Bool := true
   printNewMVars: Bool := false

Pantograph/Serial.lean

@@ -269,7 +269,7 @@ protected def GoalState.serializeGoals (state: GoalState) (parent: Option GoalSt
     | .none => throwError s!"Metavariable does not exist in context {goal.name}"
 
 /-- Print the metavariables in a readable format -/
-protected def GoalState.print (goalState: GoalState) (options: Protocol.GoalPrint := {}): MetaM Unit := do
+protected def GoalState.print (goalState: GoalState) (options: Protocol.GoalDiag := {}): MetaM Unit := do
   let savedState := goalState.savedState
   savedState.term.meta.restore
   let goals := savedState.tactic.goals

README.md

@@ -76,8 +76,9 @@ See `Pantograph/Commands.lean` for a description of the parameters and return va
   have to be set via command line arguments.), for options, see `Pantograph/Commands.lean`
 - `options.print`: Display the current set of options
 - `goal.start {["name": <name>], ["expr": <expr>], ["copyFrom": <symbol>]}`: Start a new goal from a given expression or symbol
-- `goal.tactic {"goalId": <id>, "tactic": <tactic>}`: Execute a tactic string on a given goal
-- `goal.remove {"goalIds": [<id>]}"`: Remove a bunch of stored goals.
+- `goal.tactic {"stateId": <id>, "goalId": <id>, ["tactic": <tactic>], ["expr": <expr>]}`: Execute a tactic string on a given goal
+- `goal.remove {"stateIds": [<id>]}"`: Remove a bunch of stored goals.
+- `goal.print {"stateId": <id>}"`: Print a goal state
 - `stat`: Display resource usage
 
 ## Errors

Test/Proofs.lean

@@ -188,21 +188,21 @@ def proof_arith: TestM Unit := do
       addTest $ assertUnreachable $ other.toString
       return ()
   addTest $ LSpec.check "intros" (state1.goals.length = 1)
-  addTest $ LSpec.test "(1 root)" state1.rootExpr.isNone
+  addTest $ LSpec.test "(1 root)" state1.rootExpr?.isNone
   let state2 ← match ← state1.execute (goalId := 0) (tactic := "simp [Nat.add_assoc, Nat.add_comm, Nat.add_left_comm, Nat.mul_comm, Nat.mul_assoc, Nat.mul_left_comm] at *") with
     | .success state => pure state
     | other => do
       addTest $ assertUnreachable $ other.toString
       return ()
   addTest $ LSpec.check "simp ..." (state2.goals.length = 1)
-  addTest $ LSpec.check "(2 root)" state2.rootExpr.isNone
+  addTest $ LSpec.check "(2 root)" state2.rootExpr?.isNone
   let state3 ← match ← state2.execute (goalId := 0) (tactic := "assumption") with
     | .success state => pure state
     | other => do
       addTest $ assertUnreachable $ other.toString
       return ()
   addTest $ LSpec.test "assumption" state3.goals.isEmpty
-  addTest $ LSpec.check "(3 root)" state3.rootExpr.isSome
+  addTest $ LSpec.check "(3 root)" state3.rootExpr?.isSome
   return ()
 
 -- Two ways to write the same theorem
@@ -255,7 +255,7 @@ def proof_or_comm: TestM Unit := do
       addTest $ assertUnreachable $ other.toString
       return ()
   addTest $ LSpec.check "  assumption" state4_1.goals.isEmpty
-  addTest $ LSpec.check "(4_1 root)" state4_1.rootExpr.isNone
+  addTest $ LSpec.check "(4_1 root)" state4_1.rootExpr?.isNone
   let state3_2 ← match ← state2.execute (goalId := 1) (tactic := "apply Or.inl") with
     | .success state => pure state
     | other => do
@@ -268,7 +268,7 @@ def proof_or_comm: TestM Unit := do
       addTest $ assertUnreachable $ other.toString
       return ()
   addTest $ LSpec.check "  assumption" state4_2.goals.isEmpty
-  addTest $ LSpec.check "(4_2 root)" state4_2.rootExpr.isNone
+  addTest $ LSpec.check "(4_2 root)" state4_2.rootExpr?.isNone
   -- Ensure the proof can continue from `state4_2`.
   let state2b ← match state2.continue state4_2 with
     | .error msg => do
@@ -288,7 +288,7 @@ def proof_or_comm: TestM Unit := do
       addTest $ assertUnreachable $ other.toString
       return ()
   addTest $ LSpec.check "  assumption" state4_1.goals.isEmpty
-  addTest $ LSpec.check "(4_1 root)" state4_1.rootExpr.isSome
+  addTest $ LSpec.check "(4_1 root)" state4_1.rootExpr?.isSome
 
   return ()
   where
@@ -319,14 +319,14 @@ def proof_m_couple: TestM Unit := do
       return ()
   addTest $ LSpec.check "apply Nat.le_trans" ((← state1.serializeGoals (options := ← read)).map (·.target.pp?) =
     #[.some "2 ≤ ?m", .some "?m ≤ 5", .some "Nat"])
-  addTest $ LSpec.test "(1 root)" state1.rootExpr.isNone
+  addTest $ LSpec.test "(1 root)" state1.rootExpr?.isNone
   -- Set m to 3
   let state2 ← match ← state1.execute (goalId := 2) (tactic := "exact 3") with
     | .success state => pure state
     | other => do
       addTest $ assertUnreachable $ other.toString
       return ()
-  addTest $ LSpec.test "(1b root)" state2.rootExpr.isNone
+  addTest $ LSpec.test "(1b root)" state2.rootExpr?.isNone
   let state1b ← match state1.continue state2 with
     | .error msg => do
       addTest $ assertUnreachable $ msg
@@ -334,7 +334,7 @@ def proof_m_couple: TestM Unit := do
     | .ok state => pure state
   addTest $ LSpec.check "exact 3" ((← state1b.serializeGoals (options := ← read)).map (·.target.pp?) =
     #[.some "2 ≤ 3", .some "3 ≤ 5"])
-  addTest $ LSpec.test "(2 root)" state1b.rootExpr.isNone
+  addTest $ LSpec.test "(2 root)" state1b.rootExpr?.isNone
   return ()
 
 def proof_proposition_generation: TestM Unit := do
@@ -355,7 +355,7 @@ def proof_proposition_generation: TestM Unit := do
       buildGoal [] "?fst" (caseName? := .some "snd"),
       buildGoal [] "Prop" (caseName? := .some "fst")
       ])
-  addTest $ LSpec.test "(1 root)" state1.rootExpr.isNone
+  addTest $ LSpec.test "(1 root)" state1.rootExpr?.isNone
 
   let state2 ← match ← state1.tryAssign (goalId := 0) (expr := "λ (x: Nat) => _") with
     | .success state => pure state
@@ -364,7 +364,7 @@ def proof_proposition_generation: TestM Unit := do
       return ()
   addTest $ LSpec.check ":= λ (x: Nat), _" ((← state2.serializeGoals (options := ← read)).map (·.target.pp?) =
     #[.some "Nat → Prop", .some "∀ (x : Nat), ?m.29 x"])
-  addTest $ LSpec.test "(2 root)" state2.rootExpr.isNone
+  addTest $ LSpec.test "(2 root)" state2.rootExpr?.isNone
 
   let state3 ← match ← state2.tryAssign (goalId := 1) (expr := "fun x => Eq.refl x") with
     | .success state => pure state
@@ -373,7 +373,7 @@ def proof_proposition_generation: TestM Unit := do
       return ()
   addTest $ LSpec.check ":= Eq.refl" ((← state3.serializeGoals (options := ← read)).map (·.target.pp?) =
     #[])
-  addTest $ LSpec.test "(3 root)" state3.rootExpr.isSome
+  addTest $ LSpec.test "(3 root)" state3.rootExpr?.isSome
   return ()
 
 def suite: IO LSpec.TestSeq := do