diff --git a/Pantograph.lean b/Pantograph.lean
index c637303..4272001 100644
--- a/Pantograph.lean
+++ b/Pantograph.lean
@@ -1,9 +1,10 @@
+import Lean.Data.HashMap
+import Pantograph.Compile
+import Pantograph.Environment
 import Pantograph.Goal
+import Pantograph.Library
 import Pantograph.Protocol
 import Pantograph.Serial
-import Pantograph.Environment
-import Pantograph.Library
-import Lean.Data.HashMap
 
 namespace Pantograph
 
@@ -44,6 +45,7 @@ def execute (command: Protocol.Command): MainM Lean.Json := do
   | "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}"
@@ -190,5 +192,20 @@ def execute (command: Protocol.Command): MainM Lean.Json := do
     | .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
diff --git a/Pantograph/Compile.lean b/Pantograph/Compile.lean
new file mode 100644
index 0000000..15081d9
--- /dev/null
+++ b/Pantograph/Compile.lean
@@ -0,0 +1,25 @@
+/- Adapted from lean-training-data by semorrison -/
+import Pantograph.Protocol
+import Pantograph.Compile.Frontend
+import Pantograph.Compile.Elab
+
+
+open Lean
+
+namespace Pantograph.Compile
+
+def collectTacticsFromCompilation (steps : List CompilationStep) : IO (List Protocol.InvokedTactic) := do
+  let infoTrees := steps.bind (·.trees)
+  let tacticInfoTrees := infoTrees.bind λ tree => tree.filter λ
+    | info@(.ofTacticInfo _) => info.isOriginal
+    | _ => false
+  let tactics := tacticInfoTrees.bind collectTactics
+  tactics.mapM λ invocation => do
+    let goalBefore := (Format.joinSep (← invocation.goalState) "\n").pretty
+    let goalAfter := (Format.joinSep (← invocation.goalStateAfter) "\n").pretty
+    let tactic ← invocation.ctx.runMetaM {} do
+      let t ← Lean.PrettyPrinter.ppTactic ⟨invocation.info.stx⟩
+      return t.pretty
+    return { goalBefore, goalAfter, tactic }
+
+end Pantograph.Compile
diff --git a/Pantograph/Compile/Elab.lean b/Pantograph/Compile/Elab.lean
new file mode 100644
index 0000000..79833f3
--- /dev/null
+++ b/Pantograph/Compile/Elab.lean
@@ -0,0 +1,146 @@
+
+import Lean.Elab.Import
+import Lean.Elab.Command
+import Lean.Elab.InfoTree
+
+import Pantograph.Compile.Frontend
+
+open Lean
+
+namespace Lean.Elab.Info
+/-- The `Syntax` for a `Lean.Elab.Info`, if there is one. -/
+protected def stx? : Info → Option Syntax
+  | .ofTacticInfo         info => info.stx
+  | .ofTermInfo           info => info.stx
+  | .ofCommandInfo        info => info.stx
+  | .ofMacroExpansionInfo info => info.stx
+  | .ofOptionInfo         info => info.stx
+  | .ofFieldInfo          info => info.stx
+  | .ofCompletionInfo     info => info.stx
+  | .ofUserWidgetInfo     info => info.stx
+  | .ofCustomInfo         info => info.stx
+  | .ofFVarAliasInfo      _    => none
+  | .ofFieldRedeclInfo    info => info.stx
+  | .ofOmissionInfo       info => info.stx
+/-- Is the `Syntax` for this `Lean.Elab.Info` original, or synthetic? -/
+protected def isOriginal (i : Info) : Bool :=
+  match i.stx? with
+  | none => true   -- Somewhat unclear what to do with `FVarAliasInfo`, so be conservative.
+  | some stx => match stx.getHeadInfo with
+    | .original .. => true
+    | _ => false
+end Lean.Elab.Info
+
+namespace Lean.Elab.TacticInfo
+
+/-- Find the name for the outermost `Syntax` in this `TacticInfo`. -/
+def name? (t : TacticInfo) : Option Name :=
+  match t.stx with
+  | Syntax.node _ n _ => some n
+  | _ => none
+/-- Decide whether a tactic is "substantive",
+or is merely a tactic combinator (e.g. `by`, `;`, multiline tactics, parenthesized tactics). -/
+def isSubstantive (t : TacticInfo) : Bool :=
+  match t.name? with
+  | none => false
+  | some `null => false
+  | some ``cdot => false
+  | some ``cdotTk => false
+  | some ``Lean.Parser.Term.byTactic => false
+  | some ``Lean.Parser.Tactic.tacticSeq => false
+  | some ``Lean.Parser.Tactic.tacticSeq1Indented => false
+  | some ``Lean.Parser.Tactic.«tactic_<;>_» => false
+  | some ``Lean.Parser.Tactic.paren => false
+  | _ => true
+
+end Lean.Elab.TacticInfo
+
+namespace Lean.Elab.InfoTree
+
+/--
+Keep `.node` nodes and `.hole` nodes satisfying predicates.
+
+Returns a `List InfoTree`, although in most situations this will be a singleton.
+-/
+partial def filter (p : Info → Bool) (m : MVarId → Bool := fun _ => false) :
+    InfoTree → List InfoTree
+  | .context ctx tree => tree.filter p m |>.map (.context ctx)
+  | .node info children =>
+    if p info then
+      [.node info (children.toList.map (filter p m)).join.toPArray']
+    else
+      (children.toList.map (filter p m)).join
+  | .hole mvar => if m mvar then [.hole mvar] else []
+
+end Lean.Elab.InfoTree
+
+
+namespace Pantograph.Compile
+
+-- Info tree filtering functions
+
+structure TacticInvocation where
+  info : Elab.TacticInfo
+  ctx : Elab.ContextInfo
+  children : PersistentArray Elab.InfoTree
+namespace TacticInvocation
+
+/-- Return the range of the tactic, as a pair of file positions. -/
+protected def range (t : TacticInvocation) : Position × Position := t.ctx.fileMap.stxRange t.info.stx
+
+/-- Pretty print a tactic. -/
+protected def pp (t : TacticInvocation) : IO Format :=
+  t.ctx.runMetaM {} try
+    Lean.PrettyPrinter.ppTactic ⟨t.info.stx⟩
+  catch _ =>
+    pure "<failed to pretty print>"
+
+/-- Run a tactic on the goals stored in a `TacticInvocation`. -/
+protected def runMetaMGoalsBefore (t : TacticInvocation) (x : List MVarId → MetaM α) : IO α := do
+  t.ctx.runMetaM {} <| Meta.withMCtx t.info.mctxBefore <| x t.info.goalsBefore
+
+/-- Run a tactic on the after goals stored in a `TacticInvocation`. -/
+protected def runMetaMGoalsAfter (t : TacticInvocation) (x : List MVarId → MetaM α) : IO α := do
+  t.ctx.runMetaM {} <| Meta.withMCtx t.info.mctxAfter <| x t.info.goalsAfter
+
+/-- Run a tactic on the main goal stored in a `TacticInvocation`. -/
+protected def runMetaM (t : TacticInvocation) (x : MVarId → MetaM α) : IO α := do
+  match t.info.goalsBefore.head? with
+  | none => throw <| IO.userError s!"No goals at {← t.pp}"
+  | some g => t.runMetaMGoalsBefore fun _ => do g.withContext <| x g
+
+protected def goalState (t : TacticInvocation) : IO (List Format) := do
+  t.runMetaMGoalsBefore (fun gs => gs.mapM fun g => do Meta.ppGoal g)
+
+protected def goalStateAfter (t : TacticInvocation) : IO (List Format) := do
+  t.runMetaMGoalsAfter (fun gs => gs.mapM fun g => do Meta.ppGoal g)
+
+protected def ppExpr (t : TacticInvocation) (e : Expr) : IO Format :=
+  t.runMetaM (fun _ => do Meta.ppExpr (← instantiateMVars e))
+
+end TacticInvocation
+
+/-- Analogue of `Lean.Elab.InfoTree.findInfo?`, but that returns a list of all results. -/
+partial def findAllInfo (t : Elab.InfoTree) (ctx : Option Elab.ContextInfo) (pred : Elab.Info → Bool) :
+    List (Elab.Info × Option Elab.ContextInfo × PersistentArray Elab.InfoTree) :=
+  match t with
+  | .context inner t => findAllInfo t (inner.mergeIntoOuter? ctx) pred
+  | .node i children  =>
+      (if pred i then [(i, ctx, children)] else []) ++ children.toList.bind (fun t => findAllInfo t ctx pred)
+  | _ => []
+
+/-- Return all `TacticInfo` nodes in an `InfoTree` corresponding to tactics,
+each equipped with its relevant `ContextInfo`, and any children info trees. -/
+def collectTacticNodes (t : Elab.InfoTree) : List TacticInvocation :=
+  let infos := findAllInfo t none fun i => match i with
+    | .ofTacticInfo _ => true
+    | _ => false
+  infos.filterMap fun p => match p with
+    | (.ofTacticInfo i, some ctx, children) => .some ⟨i, ctx, children⟩
+    | _ => none
+
+def collectTactics (t : Elab.InfoTree) : List TacticInvocation :=
+  collectTacticNodes t |>.filter fun i => i.info.isSubstantive
+
+
+end Pantograph.Compile
diff --git a/Pantograph/Compile/Frontend.lean b/Pantograph/Compile/Frontend.lean
new file mode 100644
index 0000000..5cb3e63
--- /dev/null
+++ b/Pantograph/Compile/Frontend.lean
@@ -0,0 +1,86 @@
+import Lean.Parser
+import Lean.Elab.Frontend
+
+open Lean
+
+namespace Lean.FileMap
+
+/-- Extract the range of a `Syntax` expressed as lines and columns. -/
+-- Extracted from the private declaration `Lean.Elab.formatStxRange`,
+-- in `Lean.Elab.InfoTree.Main`.
+protected def stxRange (fileMap : FileMap) (stx : Syntax) : Position × Position :=
+  let pos    := stx.getPos?.getD 0
+  let endPos := stx.getTailPos?.getD pos
+  (fileMap.toPosition pos, fileMap.toPosition endPos)
+
+end Lean.FileMap
+namespace Lean.PersistentArray
+
+/--
+Drop the first `n` elements of a `PersistentArray`, returning the results as a `List`.
+-/
+-- We can't remove the `[Inhabited α]` hypotheses here until
+-- `PersistentArray`'s `GetElem` instance also does.
+protected def drop [Inhabited α] (t : PersistentArray α) (n : Nat) : List α :=
+  List.range (t.size - n) |>.map fun i => t.get! (n + i)
+
+end Lean.PersistentArray
+
+
+namespace Pantograph.Compile
+
+structure CompilationStep where
+  fileName : String
+  fileMap : FileMap
+  src : Substring
+  stx : Syntax
+  before : Environment
+  after : Environment
+  msgs : List Message
+  trees : List Elab.InfoTree
+
+
+/--
+Process one command, returning a `CompilationStep` and
+`done : Bool`, indicating whether this was the last command.
+-/
+def processOneCommand: Elab.Frontend.FrontendM (CompilationStep × Bool) := do
+  let s := (← get).commandState
+  let before := s.env
+  let done ← Elab.Frontend.processCommand
+  let stx := (← get).commands.back
+  let src := (← read).inputCtx.input.toSubstring.extract (← get).cmdPos (← get).parserState.pos
+  let s' := (← get).commandState
+  let after := s'.env
+  let msgs := s'.messages.msgs.drop s.messages.msgs.size
+  let trees := s'.infoState.trees.drop s.infoState.trees.size
+  let ⟨_, fileName, fileMap⟩  := (← read).inputCtx
+  return ({ fileName, fileMap, src, stx, before, after, msgs, trees }, done)
+
+partial def processFile : Elab.Frontend.FrontendM (List CompilationStep) := do
+  let (cmd, done) ← processOneCommand
+  if done then
+    return [cmd]
+  else
+    return cmd :: (← processFile)
+
+
+def findSourcePath (module : Name) : IO System.FilePath := do
+  return System.FilePath.mk ((← findOLean module).toString.replace ".lake/build/lib/" "") |>.withExtension "lean"
+
+def processSource (module : Name) (opts : Options := {}) : IO (List CompilationStep) := unsafe do
+  let file ← IO.FS.readFile (← findSourcePath module)
+  let inputCtx := Parser.mkInputContext file module.toString
+
+  let (header, parserState, messages) ← Parser.parseHeader inputCtx
+  let (env, messages) ← Elab.processHeader header opts messages inputCtx
+  let commandState := Elab.Command.mkState env messages opts
+  processFile.run { inputCtx }
+    |>.run' {
+    commandState := { commandState with infoState.enabled := true },
+    parserState,
+    cmdPos := parserState.pos
+  }
+
+
+end Pantograph.Compile
diff --git a/Pantograph/Protocol.lean b/Pantograph/Protocol.lean
index 17618fc..8f4f947 100644
--- a/Pantograph/Protocol.lean
+++ b/Pantograph/Protocol.lean
@@ -275,6 +275,25 @@ structure GoalDiag where
   printAll: Bool := false
   instantiate: Bool := true
 
+
+/-- Executes the Lean compiler on a single file -/
+structure CompileUnit where
+  module: String
+  -- If set to true, query the string boundaries of compilation units
+  compilationUnits: Bool := false
+  -- If set to true, collect tactic invocations
+  invocations: Bool := false
+  deriving Lean.FromJson
+structure InvokedTactic where
+  goalBefore: String
+  goalAfter: String
+  tactic: String
+  deriving Lean.ToJson
+structure CompileUnitResult where
+  units?: Option $ List (Nat × Nat)
+  invocations?: Option $ List InvokedTactic
+  deriving Lean.ToJson
+
 abbrev CR α := Except InteractionError α
 
 end Pantograph.Protocol
diff --git a/Pantograph/Version.lean b/Pantograph/Version.lean
index 4ab34c4..207b597 100644
--- a/Pantograph/Version.lean
+++ b/Pantograph/Version.lean
@@ -1,6 +1,6 @@
 namespace Pantograph
 
 @[export pantograph_version]
-def version := "0.2.15"
+def version := "0.2.16"
 
 end Pantograph