Main.lean

@@ -4,6 +4,7 @@ import Lean.Environment
 import Pantograph.Version
 import Pantograph.Library
 import Pantograph
+import Repl
 
 -- Main IO functions
 open Pantograph

Pantograph.lean

@@ -1,4 +1,3 @@
-import Lean.Data.HashMap
 import Pantograph.Compile
 import Pantograph.Condensed
 import Pantograph.Environment
@@ -6,224 +5,4 @@ import Pantograph.Goal
 import Pantograph.Library
 import Pantograph.Protocol
 import Pantograph.Serial
-
-namespace Pantograph
-
-structure Context where
-  imports: List String
-
-/-- Stores state of the REPL -/
-structure State where
-  options: Protocol.Options := {}
-  nextId: Nat := 0
-  goalStates: Lean.HashMap Nat GoalState := Lean.HashMap.empty
-
-/-- Main state monad for executing commands -/
-abbrev MainM := ReaderT Context (StateT State Lean.CoreM)
-
--- HACK: For some reason writing `CommandM α := MainM (Except ... α)` disables
--- certain monadic features in `MainM`
-abbrev CR α := Except Protocol.InteractionError α
-
-def runMetaInMainM { α } (metaM: Lean.MetaM α): MainM α :=
-  metaM.run'
-def runTermElabInMainM { α } (termElabM: Lean.Elab.TermElabM α) : MainM α :=
-  termElabM.run' (ctx := Condensed.elabContext) |>.run'
-
-def execute (command: Protocol.Command): MainM Lean.Json := do
-  let run { α β: Type } [Lean.FromJson α] [Lean.ToJson β] (comm: α → MainM (CR β)): MainM Lean.Json :=
-    match Lean.fromJson? command.payload with
-    | .ok args => do
-      match (← comm args) with
-      | .ok result =>  return Lean.toJson result
-      | .error ierror => return Lean.toJson ierror
-    | .error error => return Lean.toJson $ errorCommand s!"Unable to parse json: {error}"
-  match command.cmd with
-  | "reset"         => run reset
-  | "stat"          => run stat
-  | "expr.echo"     => run expr_echo
-  | "env.catalog"   => run env_catalog
-  | "env.inspect"   => run env_inspect
-  | "env.add"       => run env_add
-  | "options.set"   => run options_set
-  | "options.print" => run options_print
-  | "goal.start"    => run goal_start
-  | "goal.tactic"   => run goal_tactic
-  | "goal.continue" => run goal_continue
-  | "goal.delete"   => run goal_delete
-  | "goal.print"    => run goal_print
-  | "compile.unit"  => run compile_unit
-  | cmd =>
-    let error: Protocol.InteractionError :=
-      errorCommand s!"Unknown command {cmd}"
-    return Lean.toJson error
-  where
-  errorCommand := errorI "command"
-  errorIndex := errorI "index"
-  -- Command Functions
-  reset (_: Protocol.Reset): MainM (CR Protocol.StatResult) := do
-    let state ← get
-    let nGoals := state.goalStates.size
-    set { state with nextId := 0, goalStates := Lean.HashMap.empty }
-    return .ok { nGoals }
-  stat (_: Protocol.Stat): MainM (CR Protocol.StatResult) := do
-    let state ← get
-    let nGoals := state.goalStates.size
-    return .ok { nGoals }
-  env_catalog (args: Protocol.EnvCatalog): MainM (CR Protocol.EnvCatalogResult) := do
-    let result ← Environment.catalog args
-    return .ok result
-  env_inspect (args: Protocol.EnvInspect): MainM (CR Protocol.EnvInspectResult) := do
-    let state ← get
-    Environment.inspect args state.options
-  env_add (args: Protocol.EnvAdd): MainM (CR Protocol.EnvAddResult) := do
-    Environment.addDecl args
-  expr_echo (args: Protocol.ExprEcho): MainM (CR Protocol.ExprEchoResult) := do
-    let state ← get
-    exprEcho args.expr (expectedType? := args.type?) (levels := args.levels.getD #[]) (options := state.options)
-  options_set (args: Protocol.OptionsSet): MainM (CR Protocol.OptionsSetResult) := do
-    let state ← get
-    let options := state.options
-    set { state with
-      options := {
-        -- FIXME: This should be replaced with something more elegant
-        printJsonPretty := args.printJsonPretty?.getD options.printJsonPretty,
-        printExprPretty := args.printExprPretty?.getD options.printExprPretty,
-        printExprAST := args.printExprAST?.getD options.printExprAST,
-        printDependentMVars := args.printDependentMVars?.getD options.printDependentMVars,
-        noRepeat := args.noRepeat?.getD options.noRepeat,
-        printAuxDecls := args.printAuxDecls?.getD options.printAuxDecls,
-        printImplementationDetailHyps := args.printImplementationDetailHyps?.getD options.printImplementationDetailHyps
-        automaticMode := args.automaticMode?.getD options.automaticMode,
-      }
-    }
-    return .ok {  }
-  options_print (_: Protocol.OptionsPrint): MainM (CR Protocol.Options) := do
-    return .ok (← get).options
-  goal_start (args: Protocol.GoalStart): MainM (CR Protocol.GoalStartResult) := do
-    let state ← get
-    let env ← Lean.MonadEnv.getEnv
-    let expr?: Except _ GoalState ← runTermElabInMainM (match args.expr, args.copyFrom with
-      | .some expr, .none => goalStartExpr expr (args.levels.getD #[])
-      | .none, .some copyFrom =>
-        (match env.find? <| copyFrom.toName with
-        | .none => return .error <| errorIndex s!"Symbol not found: {copyFrom}"
-        | .some cInfo => return .ok (← GoalState.create cInfo.type))
-      | _, _ =>
-        return .error <| errorI "arguments" "Exactly one of {expr, copyFrom} must be supplied")
-    match expr? with
-    | .error error => return .error error
-    | .ok goalState =>
-      let stateId := state.nextId
-      set { state with
-        goalStates := state.goalStates.insert stateId goalState,
-        nextId := state.nextId + 1
-      }
-      return .ok { stateId, root := goalState.root.name.toString }
-  goal_tactic (args: Protocol.GoalTactic): MainM (CR Protocol.GoalTacticResult) := do
-    let state ← get
-    let .some goalState := state.goalStates.find? args.stateId |
-      return .error $ errorIndex s!"Invalid state index {args.stateId}"
-    let .some goal := goalState.goals.get? args.goalId |
-      return .error $ errorIndex s!"Invalid goal index {args.goalId}"
-    let nextGoalState?: Except _ TacticResult ← runTermElabInMainM do
-      match args.tactic?, args.expr?, args.have?, args.calc?, args.conv?  with
-      | .some tactic, .none, .none, .none, .none => do
-        pure <| Except.ok <| ← goalState.tryTactic goal tactic
-      | .none, .some expr, .none, .none, .none => do
-        pure <| Except.ok <| ← goalState.tryAssign goal expr
-      | .none, .none, .some type, .none, .none => do
-        let binderName := args.binderName?.getD ""
-        pure <| Except.ok <| ← goalState.tryHave goal binderName type
-      | .none, .none, .none, .some pred, .none => do
-        pure <| Except.ok <| ← goalState.tryCalc goal pred
-      | .none, .none, .none, .none, .some true => do
-        pure <| Except.ok <| ← goalState.conv goal
-      | .none, .none, .none, .none, .some false => do
-        pure <| Except.ok <| ← goalState.convExit
-      | _, _, _, _, _ =>
-        let error := errorI "arguments" "Exactly one of {tactic, expr, have, calc, conv} must be supplied"
-        pure $ Except.error $ error
-    match nextGoalState? with
-    | .error error => return .error error
-    | .ok (.success nextGoalState) => do
-      let nextGoalState ← match state.options.automaticMode, args.conv? with
-        | true, .none => do
-          let .ok result := nextGoalState.resume goalState.goals | throwError "Resuming known goals"
-          pure result
-        | true, .some true => pure nextGoalState
-        | true, .some false => do
-          let .some (_, _, dormantGoals) := goalState.convMVar? | throwError "If conv exit succeeded this should not fail"
-          let .ok result := nextGoalState.resume dormantGoals | throwError "Resuming known goals"
-          pure result
-        | false, _ => pure nextGoalState
-      let nextStateId := state.nextId
-      set { state with
-        goalStates := state.goalStates.insert state.nextId nextGoalState,
-        nextId := state.nextId + 1,
-      }
-      let goals ← nextGoalState.serializeGoals (parent := .some goalState) (options := state.options) |>.run'
-      return .ok {
-        nextStateId? := .some nextStateId,
-        goals? := .some goals,
-      }
-    | .ok (.parseError message) =>
-      return .ok { parseError? := .some message }
-    | .ok (.invalidAction message) =>
-      return .error $ errorI "invalid" message
-    | .ok (.failure messages) =>
-      return .ok { tacticErrors? := .some messages }
-  goal_continue (args: Protocol.GoalContinue): MainM (CR Protocol.GoalContinueResult) := do
-    let state ← get
-    match state.goalStates.find? args.target with
-    | .none => return .error $ errorIndex s!"Invalid state index {args.target}"
-    | .some target => do
-      let nextState? ← match args.branch?, args.goals? with
-        | .some branchId, .none => do
-          match state.goalStates.find? branchId with
-          | .none => return .error $ errorIndex s!"Invalid state index {branchId}"
-          | .some branch => pure $ goalContinue target branch
-        | .none, .some goals =>
-          pure $ goalResume target goals
-        | _, _ => return .error <| errorI "arguments" "Exactly one of {branch, goals} must be supplied"
-      match nextState? with
-      | .error error => return .error <| errorI "structure" error
-      | .ok nextGoalState =>
-        let nextStateId := state.nextId
-        set { state with
-          goalStates := state.goalStates.insert nextStateId nextGoalState,
-          nextId := state.nextId + 1
-        }
-        let goals ← goalSerialize nextGoalState (options := state.options)
-        return .ok {
-          nextStateId,
-          goals,
-        }
-  goal_delete (args: Protocol.GoalDelete): MainM (CR Protocol.GoalDeleteResult) := do
-    let state ← get
-    let goalStates := args.stateIds.foldl (λ map id => map.erase 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.find? args.stateId with
-    | .none => return .error $ errorIndex s!"Invalid state index {args.stateId}"
-    | .some goalState => runMetaM <| do
-      return .ok (← goalPrint goalState state.options)
-  compile_unit (args: Protocol.CompileUnit): MainM (CR Protocol.CompileUnitResult) := do
-    let module := args.module.toName
-    try
-      let steps ← Compile.processSource module
-      let units? := if args.compilationUnits then
-          .some $ steps.map λ step => (step.src.startPos.byteIdx, step.src.stopPos.byteIdx)
-        else
-          .none
-      let invocations? ← if args.invocations then
-          pure $ .some (← Compile.collectTacticsFromCompilation steps)
-        else
-          pure .none
-      return .ok { units?, invocations? }
-    catch e =>
-      return .error $ errorI "compile" (← e.toMessageData.toString)
-
-end Pantograph
+import Pantograph.Version

Pantograph/Goal.lean

@@ -307,7 +307,7 @@ protected def GoalState.convExit (state: GoalState):
     return .failure #[← exception.toMessageData.toString]
 
 protected def GoalState.calcPrevRhsOf? (state: GoalState) (goal: MVarId): Option Expr := do
-  let (mvarId, rhs ) ← state.calcPrevRhs?
+  let (mvarId, rhs) ← state.calcPrevRhs?
   if mvarId == goal then
     .some rhs
   else
@@ -352,9 +352,8 @@ protected def GoalState.tryCalc (state: GoalState) (goal: MVarId) (pred: String)
       (userName := tag ++ `calc)
     let mvarBranch := proof.mvarId!
 
-    let calcPrevRhs? := Option.some (goal, rhs)
     let mut proofType ← Meta.inferType proof
-    let mut remainder := Option.none
+    let mut remainder? := Option.none
 
     -- The calc tactic either solves the main goal or leaves another relation.
     -- Replace the main goal, and save the new goal if necessary
@@ -367,10 +366,11 @@ protected def GoalState.tryCalc (state: GoalState) (goal: MVarId) (pred: String)
       let lastStepGoal ← Meta.mkFreshExprSyntheticOpaqueMVar lastStep tag
       (proof, proofType) ← Elab.Term.mkCalcTrans proof proofType lastStepGoal lastStep
       unless ← Meta.isDefEq proofType target do throwFailed
-      remainder := .some lastStepGoal.mvarId!
+      remainder? := .some lastStepGoal.mvarId!
     goal.assign proof
 
-    let goals := [ mvarBranch ] ++ remainder.toList
+    let goals := [ mvarBranch ] ++ remainder?.toList
+    let calcPrevRhs? := remainder?.map $ λ g => (g, rhs)
     return .success {
       root := state.root,
       savedState := {

Repl.lean

@@ -0,0 +1,223 @@
+import Lean.Data.HashMap
+import Pantograph
+
+namespace Pantograph
+
+structure Context where
+  imports: List String
+
+/-- Stores state of the REPL -/
+structure State where
+  options: Protocol.Options := {}
+  nextId: Nat := 0
+  goalStates: Lean.HashMap Nat GoalState := Lean.HashMap.empty
+
+/-- Main state monad for executing commands -/
+abbrev MainM := ReaderT Context (StateT State Lean.CoreM)
+
+-- HACK: For some reason writing `CommandM α := MainM (Except ... α)` disables
+-- certain monadic features in `MainM`
+abbrev CR α := Except Protocol.InteractionError α
+
+def runMetaInMainM { α } (metaM: Lean.MetaM α): MainM α :=
+  metaM.run'
+def runTermElabInMainM { α } (termElabM: Lean.Elab.TermElabM α) : MainM α :=
+  termElabM.run' (ctx := Condensed.elabContext) |>.run'
+
+def execute (command: Protocol.Command): MainM Lean.Json := do
+  let run { α β: Type } [Lean.FromJson α] [Lean.ToJson β] (comm: α → MainM (CR β)): MainM Lean.Json :=
+    match Lean.fromJson? command.payload with
+    | .ok args => do
+      match (← comm args) with
+      | .ok result =>  return Lean.toJson result
+      | .error ierror => return Lean.toJson ierror
+    | .error error => return Lean.toJson $ errorCommand s!"Unable to parse json: {error}"
+  match command.cmd with
+  | "reset"         => run reset
+  | "stat"          => run stat
+  | "expr.echo"     => run expr_echo
+  | "env.catalog"   => run env_catalog
+  | "env.inspect"   => run env_inspect
+  | "env.add"       => run env_add
+  | "options.set"   => run options_set
+  | "options.print" => run options_print
+  | "goal.start"    => run goal_start
+  | "goal.tactic"   => run goal_tactic
+  | "goal.continue" => run goal_continue
+  | "goal.delete"   => run goal_delete
+  | "goal.print"    => run goal_print
+  | "compile.unit"  => run compile_unit
+  | cmd =>
+    let error: Protocol.InteractionError :=
+      errorCommand s!"Unknown command {cmd}"
+    return Lean.toJson error
+  where
+  errorCommand := errorI "command"
+  errorIndex := errorI "index"
+  -- Command Functions
+  reset (_: Protocol.Reset): MainM (CR Protocol.StatResult) := do
+    let state ← get
+    let nGoals := state.goalStates.size
+    set { state with nextId := 0, goalStates := Lean.HashMap.empty }
+    return .ok { nGoals }
+  stat (_: Protocol.Stat): MainM (CR Protocol.StatResult) := do
+    let state ← get
+    let nGoals := state.goalStates.size
+    return .ok { nGoals }
+  env_catalog (args: Protocol.EnvCatalog): MainM (CR Protocol.EnvCatalogResult) := do
+    let result ← Environment.catalog args
+    return .ok result
+  env_inspect (args: Protocol.EnvInspect): MainM (CR Protocol.EnvInspectResult) := do
+    let state ← get
+    Environment.inspect args state.options
+  env_add (args: Protocol.EnvAdd): MainM (CR Protocol.EnvAddResult) := do
+    Environment.addDecl args
+  expr_echo (args: Protocol.ExprEcho): MainM (CR Protocol.ExprEchoResult) := do
+    let state ← get
+    exprEcho args.expr (expectedType? := args.type?) (levels := args.levels.getD #[]) (options := state.options)
+  options_set (args: Protocol.OptionsSet): MainM (CR Protocol.OptionsSetResult) := do
+    let state ← get
+    let options := state.options
+    set { state with
+      options := {
+        -- FIXME: This should be replaced with something more elegant
+        printJsonPretty := args.printJsonPretty?.getD options.printJsonPretty,
+        printExprPretty := args.printExprPretty?.getD options.printExprPretty,
+        printExprAST := args.printExprAST?.getD options.printExprAST,
+        printDependentMVars := args.printDependentMVars?.getD options.printDependentMVars,
+        noRepeat := args.noRepeat?.getD options.noRepeat,
+        printAuxDecls := args.printAuxDecls?.getD options.printAuxDecls,
+        printImplementationDetailHyps := args.printImplementationDetailHyps?.getD options.printImplementationDetailHyps
+        automaticMode := args.automaticMode?.getD options.automaticMode,
+      }
+    }
+    return .ok {  }
+  options_print (_: Protocol.OptionsPrint): MainM (CR Protocol.Options) := do
+    return .ok (← get).options
+  goal_start (args: Protocol.GoalStart): MainM (CR Protocol.GoalStartResult) := do
+    let state ← get
+    let env ← Lean.MonadEnv.getEnv
+    let expr?: Except _ GoalState ← runTermElabInMainM (match args.expr, args.copyFrom with
+      | .some expr, .none => goalStartExpr expr (args.levels.getD #[])
+      | .none, .some copyFrom =>
+        (match env.find? <| copyFrom.toName with
+        | .none => return .error <| errorIndex s!"Symbol not found: {copyFrom}"
+        | .some cInfo => return .ok (← GoalState.create cInfo.type))
+      | _, _ =>
+        return .error <| errorI "arguments" "Exactly one of {expr, copyFrom} must be supplied")
+    match expr? with
+    | .error error => return .error error
+    | .ok goalState =>
+      let stateId := state.nextId
+      set { state with
+        goalStates := state.goalStates.insert stateId goalState,
+        nextId := state.nextId + 1
+      }
+      return .ok { stateId, root := goalState.root.name.toString }
+  goal_tactic (args: Protocol.GoalTactic): MainM (CR Protocol.GoalTacticResult) := do
+    let state ← get
+    let .some goalState := state.goalStates.find? args.stateId |
+      return .error $ errorIndex s!"Invalid state index {args.stateId}"
+    let .some goal := goalState.goals.get? args.goalId |
+      return .error $ errorIndex s!"Invalid goal index {args.goalId}"
+    let nextGoalState?: Except _ TacticResult ← runTermElabInMainM do
+      match args.tactic?, args.expr?, args.have?, args.calc?, args.conv?  with
+      | .some tactic, .none, .none, .none, .none => do
+        pure <| Except.ok <| ← goalState.tryTactic goal tactic
+      | .none, .some expr, .none, .none, .none => do
+        pure <| Except.ok <| ← goalState.tryAssign goal expr
+      | .none, .none, .some type, .none, .none => do
+        let binderName := args.binderName?.getD ""
+        pure <| Except.ok <| ← goalState.tryHave goal binderName type
+      | .none, .none, .none, .some pred, .none => do
+        pure <| Except.ok <| ← goalState.tryCalc goal pred
+      | .none, .none, .none, .none, .some true => do
+        pure <| Except.ok <| ← goalState.conv goal
+      | .none, .none, .none, .none, .some false => do
+        pure <| Except.ok <| ← goalState.convExit
+      | _, _, _, _, _ =>
+        let error := errorI "arguments" "Exactly one of {tactic, expr, have, calc, conv} must be supplied"
+        pure $ Except.error $ error
+    match nextGoalState? with
+    | .error error => return .error error
+    | .ok (.success nextGoalState) => do
+      let nextGoalState ← match state.options.automaticMode, args.conv? with
+        | true, .none => do
+          let .ok result := nextGoalState.resume goalState.goals | throwError "Resuming known goals"
+          pure result
+        | true, .some true => pure nextGoalState
+        | true, .some false => do
+          let .some (_, _, dormantGoals) := goalState.convMVar? | throwError "If conv exit succeeded this should not fail"
+          let .ok result := nextGoalState.resume dormantGoals | throwError "Resuming known goals"
+          pure result
+        | false, _ => pure nextGoalState
+      let nextStateId := state.nextId
+      set { state with
+        goalStates := state.goalStates.insert state.nextId nextGoalState,
+        nextId := state.nextId + 1,
+      }
+      let goals ← nextGoalState.serializeGoals (parent := .some goalState) (options := state.options) |>.run'
+      return .ok {
+        nextStateId? := .some nextStateId,
+        goals? := .some goals,
+      }
+    | .ok (.parseError message) =>
+      return .ok { parseError? := .some message }
+    | .ok (.invalidAction message) =>
+      return .error $ errorI "invalid" message
+    | .ok (.failure messages) =>
+      return .ok { tacticErrors? := .some messages }
+  goal_continue (args: Protocol.GoalContinue): MainM (CR Protocol.GoalContinueResult) := do
+    let state ← get
+    match state.goalStates.find? args.target with
+    | .none => return .error $ errorIndex s!"Invalid state index {args.target}"
+    | .some target => do
+      let nextState? ← match args.branch?, args.goals? with
+        | .some branchId, .none => do
+          match state.goalStates.find? branchId with
+          | .none => return .error $ errorIndex s!"Invalid state index {branchId}"
+          | .some branch => pure $ goalContinue target branch
+        | .none, .some goals =>
+          pure $ goalResume target goals
+        | _, _ => return .error <| errorI "arguments" "Exactly one of {branch, goals} must be supplied"
+      match nextState? with
+      | .error error => return .error <| errorI "structure" error
+      | .ok nextGoalState =>
+        let nextStateId := state.nextId
+        set { state with
+          goalStates := state.goalStates.insert nextStateId nextGoalState,
+          nextId := state.nextId + 1
+        }
+        let goals ← goalSerialize nextGoalState (options := state.options)
+        return .ok {
+          nextStateId,
+          goals,
+        }
+  goal_delete (args: Protocol.GoalDelete): MainM (CR Protocol.GoalDeleteResult) := do
+    let state ← get
+    let goalStates := args.stateIds.foldl (λ map id => map.erase 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.find? args.stateId with
+    | .none => return .error $ errorIndex s!"Invalid state index {args.stateId}"
+    | .some goalState => runMetaM <| do
+      return .ok (← goalPrint goalState state.options)
+  compile_unit (args: Protocol.CompileUnit): MainM (CR Protocol.CompileUnitResult) := do
+    let module := args.module.toName
+    try
+      let steps ← Compile.processSource module
+      let units? := if args.compilationUnits then
+          .some $ steps.map λ step => (step.src.startPos.byteIdx, step.src.stopPos.byteIdx)
+        else
+          .none
+      let invocations? ← if args.invocations then
+          pure $ .some (← Compile.collectTacticsFromCompilation steps)
+        else
+          pure .none
+      return .ok { units?, invocations? }
+    catch e =>
+      return .error $ errorI "compile" (← e.toMessageData.toString)
+
+end Pantograph

Test/Integration.lean

@@ -2,6 +2,8 @@
  -/
 import LSpec
 import Pantograph
+import Repl
+
 namespace Pantograph.Test.Integration
 open Pantograph
 

flake.nix

@@ -37,14 +37,25 @@
       };
       project = leanPkgs.buildLeanPackage {
         name = "Pantograph";
-        roots = [ "Main" "Pantograph" ];
-        src = pkgs.lib.cleanSourceWith {
+        roots = [ "Pantograph" ];
+        src = pkgs.lib.cleanSource (pkgs.lib.cleanSourceWith {
           src = ./.;
           filter = path: type:
             !(pkgs.lib.hasInfix "/Test/" path) &&
             !(pkgs.lib.hasSuffix ".md" path) &&
-            !(pkgs.lib.hasSuffix "Makefile" path);
-        };
+            !(pkgs.lib.hasSuffix "Repl.lean" path);
+        });
+      };
+      repl = leanPkgs.buildLeanPackage {
+        name = "Repl";
+        roots = [ "Main" "Repl" ];
+        deps = [ project ];
+        src = pkgs.lib.cleanSource (pkgs.lib.cleanSourceWith {
+          src = ./.;
+          filter = path: type:
+            !(pkgs.lib.hasInfix "/Test/" path) &&
+            !(pkgs.lib.hasSuffix ".md" path);
+        });
       };
       test = leanPkgs.buildLeanPackage {
         name = "Test";
@@ -52,18 +63,19 @@
         # root begins (e.g. `import Test.Environment` and not `import
         # Environment`) and thats where `lakefile.lean` resides.
         roots = [ "Test.Main" ];
-        deps = [ lspecLib project ];
-        src = pkgs.lib.cleanSourceWith {
+        deps = [ lspecLib repl ];
+        src = pkgs.lib.cleanSource (pkgs.lib.cleanSourceWith {
           src = ./.;
           filter = path: type:
             !(pkgs.lib.hasInfix "Pantograph" path);
-        };
+        });
       };
     in rec {
       packages = {
         inherit (leanPkgs) lean lean-all;
-        inherit (project) sharedLib executable;
-        default = project.executable;
+        inherit (project) sharedLib;
+        inherit (repl) executable;
+        default = repl.executable;
       };
       legacyPackages = {
         inherit project leanPkgs;

lakefile.lean

@@ -4,11 +4,14 @@ open Lake DSL
 package pantograph
 
 lean_lib Pantograph {
+  roots := #[`Pantograph]
   defaultFacets := #[LeanLib.sharedFacet]
 }
 
+lean_lib Repl {
+}
 @[default_target]
-lean_exe pantograph {
+lean_exe repl {
   root := `Main
   -- Solves the native symbol not found problem
   supportInterpreter := true