diff --git a/src/commonMain/kotlin/ai/hypergraph/kaliningraph/parsing/BarHillel.kt b/src/commonMain/kotlin/ai/hypergraph/kaliningraph/parsing/BarHillel.kt
index 972bbad4..b339549e 100644
--- a/src/commonMain/kotlin/ai/hypergraph/kaliningraph/parsing/BarHillel.kt
+++ b/src/commonMain/kotlin/ai/hypergraph/kaliningraph/parsing/BarHillel.kt
@@ -16,14 +16,9 @@ fun CFG.makeLevGrammar(source: List<Σᐩ>, distance: Int) =
 fun CFG.barHillelRepair(prompt: List<Σᐩ>, distance: Int) =
   makeLevGrammar(prompt, distance).enumSeq(List(prompt.size + distance) { "_" })
 
+// Specialized Bar-Hillel construction for Levenshtein FSA
 private infix fun CFG.intersectLevFSAP(fsa: FSA): CFG {
   var clock = TimeSource.Monotonic.markNow()
-  val initFinal =
-    (fsa.init * fsa.final).map { (q, r) -> "START" to listOf("[$q,START,$r]") }
-
-  val transits =
-    fsa.Q.map { (q, a, r) -> "[$q,$a,$r]" to listOf(a) }
-
   fun Triple<Σᐩ, Σᐩ, Σᐩ>.isCompatibleWith(nts: Triple<Σᐩ, Σᐩ, Σᐩ>): Boolean {
     fun Σᐩ.coords(): Pair<Int, Int> =
       (length / 2 - 1).let { substring(2, it + 2).toInt() to substring(it + 3).toInt() }
@@ -55,6 +50,12 @@ private infix fun CFG.intersectLevFSAP(fsa: FSA): CFG {
     return isCompatible()
   }
 
+  val initFinal =
+    (fsa.init * fsa.final).map { (q, r) -> "START" to listOf("[$q,START,$r]") }
+
+  val transits =
+    fsa.Q.map { (q, a, r) -> "[$q,$a,$r]" to listOf(a) }
+
   // For every production A → σ in P, for every (p, σ, q) ∈ Q × Σ × Q
   // such that δ(p, σ) = q we have the production [p, A, q] → σ in P′.
   val unitProds = unitProdRules(fsa)
@@ -124,8 +125,9 @@ fun CFG.dropVestigialProductions(
   return if (rw.size == size) this else rw.dropVestigialProductions(criteria)
 }
 
-infix fun FSA.intersect(cfg: CFG) = cfg.intersect(this)
+infix fun FSA.intersect(cfg: CFG) = cfg.freeze().intersect(this)
 
+// Generic Bar-Hillel construction for arbitrary FSA
 infix fun CFG.intersect(fsa: FSA): CFG {
   val clock = TimeSource.Monotonic.markNow()
   val initFinal =
diff --git a/src/commonMain/kotlin/ai/hypergraph/kaliningraph/parsing/CFG.kt b/src/commonMain/kotlin/ai/hypergraph/kaliningraph/parsing/CFG.kt
index 75aeb6a8..0290fd7f 100644
--- a/src/commonMain/kotlin/ai/hypergraph/kaliningraph/parsing/CFG.kt
+++ b/src/commonMain/kotlin/ai/hypergraph/kaliningraph/parsing/CFG.kt
@@ -96,7 +96,7 @@ val CFG.unitReachability by cache {
 
 val CFG.noNonterminalStubs: CFG by cache {
   println("Disabling nonterminal stubs!")
-  filter { it.RHS.none { it.isNonterminalStubIn(this) } }.toSet()
+  filter { it.RHS.none { it.isNonterminalStubIn(this) } }.toSet().freeze()
     .also { rewriteHistory.put(it, freeze().let { rewriteHistory[it]!! + listOf(it)}) }
     .also { it.blocked.addAll(blocked) }
 }
@@ -104,7 +104,7 @@ val CFG.noNonterminalStubs: CFG by cache {
 val CFG.noEpsilonOrNonterminalStubs: CFG by cache {
   println("Disabling nonterminal stubs!")
   filter { it.RHS.none { it.isNonterminalStubIn(this) } }
-    .filter { "ε" !in it.toString() }.toSet()
+    .filter { "ε" !in it.toString() }.toSet().freeze()
     .also { rewriteHistory.put(it, freeze().let { rewriteHistory[it]!! + listOf(it)}) }
     .also { it.blocked.addAll(blocked) }
 }
diff --git a/src/commonMain/kotlin/ai/hypergraph/kaliningraph/parsing/Levenshtein.kt b/src/commonMain/kotlin/ai/hypergraph/kaliningraph/parsing/Levenshtein.kt
index f40faf4b..ecba6e7f 100644
--- a/src/commonMain/kotlin/ai/hypergraph/kaliningraph/parsing/Levenshtein.kt
+++ b/src/commonMain/kotlin/ai/hypergraph/kaliningraph/parsing/Levenshtein.kt
@@ -1,7 +1,7 @@
 package ai.hypergraph.kaliningraph.parsing
 
+import ai.hypergraph.kaliningraph.*
 import ai.hypergraph.kaliningraph.automata.*
-import ai.hypergraph.kaliningraph.tokenizeByWhitespace
 import ai.hypergraph.kaliningraph.types.*
 import kotlin.math.*
 
@@ -155,7 +155,7 @@ fun <T> levenshtein(o1: List<T>, o2: List<T>): Int {
   return prev[o2.size]
 }
 
-fun levenshteinAlign(a: String, b: String) =
+fun levenshteinAlign(a: Σᐩ, b: Σᐩ): List<Pair<Σᐩ?, Σᐩ?>> =
   levenshteinAlign(a.tokenizeByWhitespace(), b.tokenizeByWhitespace())
 
 fun <T> levenshteinAlign(a: List<T>, b: List<T>): List<Pair<T?, T?>> {
@@ -204,4 +204,17 @@ fun <T> levenshteinAlign(a: List<T>, b: List<T>): List<Pair<T?, T?>> {
   val revPathA = aPathRev.reversed()
   val revPathB = bPathRev.reversed()
   return revPathA.zip(revPathB)
-}
\ No newline at end of file
+}
+
+fun <T> List<Pair<T?, T?>>.paintANSIColors(): Σᐩ =
+  joinToString(" ") { (a, b) ->
+    when {
+      // Green (insertion)
+      a == null -> "$ANSI_GREEN_BACKGROUND$b$ANSI_RESET"
+      // Red (deletion)
+      b == null -> "$ANSI_RED_BACKGROUND$a$ANSI_RESET"
+      // Orange (substitution)
+      a != b -> "$ANSI_ORANGE_BACKGROUND$b$ANSI_RESET"
+      else -> b.toString()
+    }
+  }
\ No newline at end of file
diff --git a/src/commonTest/kotlin/ai/hypergraph/kaliningraph/parsing/BarHillelTest.kt b/src/commonTest/kotlin/ai/hypergraph/kaliningraph/parsing/BarHillelTest.kt
index df0b82fe..7f67ac2d 100644
--- a/src/commonTest/kotlin/ai/hypergraph/kaliningraph/parsing/BarHillelTest.kt
+++ b/src/commonTest/kotlin/ai/hypergraph/kaliningraph/parsing/BarHillelTest.kt
@@ -102,7 +102,8 @@ class BarHillelTest {
     """.parseCFG().noEpsilonOrNonterminalStubs
 
     val origStr = "1 + 1"
-    val levFSA = makeLevFSA(origStr, 2, simpleCFG.terminals)
+    val levDist = 2
+    val levFSA = makeLevFSA(origStr, levDist, simpleCFG.terminals)
 
     val levCFG = levFSA.intersectLevFSA(simpleCFG)
 
@@ -122,8 +123,13 @@ class BarHillelTest {
     val testFail = "2 * 2"
     assertFalse(testFail in levCFG.language)
 
-    val template = List(5) { "_" }
-    val solutions = levCFG.enumSeq(template).toList().onEach { println(it) }
+    val template = List(origStr.tokenizeByWhitespace().size + levDist) { "_" }
+    val solutions = levCFG.enumSeq(template).toList().onEach {
+      val actDist = levenshtein(origStr, it)
+      val levAlgn = levenshteinAlign(origStr, it).paintANSIColors()
+      assertTrue(actDist <= levDist)
+      println(levAlgn)
+    }
     println("Found ${solutions.size} solutions within Levenshtein distance 2 of \"$origStr\"")
   }
 
@@ -188,14 +194,40 @@ class BarHillelTest {
       "${(lbhSet + efset) - (lbhSet intersect efset)}")
   }
 
+/*
+./gradlew jvmTest --tests "ai.hypergraph.kaliningraph.parsing.BarHillelTest.testIfThenBarHillel"
+*/
+  @Test
+  fun testIfThenBarHillel() {
+    val gram = Grammars.ifThen
+    val origStr = "if ( true or false then true else 1"
+    val tokens = origStr.tokenizeByWhitespace()
+    val levDist = 3
+    val levBall = makeLevFSA(origStr, levDist, gram.terminals)
+    val intGram = gram.intersectLevFSA(levBall)
+    val clock = TimeSource.Monotonic.markNow()
+    val template = List(tokens.size + levDist) { "_" }
+    intGram.enumSeq(template).distinct().onEach {
+      val levAlign = levenshteinAlign(origStr, it).paintANSIColors()
+      val actDist= levenshtein(origStr, it)
+      println(levAlign)
+
+      assertTrue(it in gram.language)
+      assertTrue(levBall.recognizes(it))
+      assertTrue(actDist <= levDist)
+    }.toList().also { println("Found ${it.size} solutions using Levenshtein/Bar-Hillel in ${clock.elapsedNow()}") }
+  }
+
 /*
 ./gradlew jvmTest --tests "ai.hypergraph.kaliningraph.parsing.BarHillelTest.testPythonBarHillel"
 */
   @Test
   fun testPythonBarHillel() {
     val gram = Grammars.seq2parsePythonCFG.noEpsilonOrNonterminalStubs
-    val toRepair = "NAME = ( NAME . NAME ( NAME NEWLINE".tokenizeByWhitespace()
-    val levBall = makeLevFSA(toRepair, 3, gram.terminals)
+    val origStr = "NAME = ( NAME . NAME ( NAME NEWLINE"
+    val toRepair = origStr.tokenizeByWhitespace()
+    val levDist = 3
+    val levBall = makeLevFSA(toRepair, levDist, gram.terminals)
 //  println(levBall.toDot())
 //  throw Exception("")
     val intGram = gram.intersectLevFSA(levBall)
@@ -209,17 +241,19 @@ class BarHillelTest {
 //    println(intGram.prettyPrint())
     val clock = TimeSource.Monotonic.markNow()
 
-    val template = List(toRepair.size + 2) { "_" }
+    val template = List(toRepair.size + levDist - 1) { "_" }
 
     val lbhSet = intGram.enumSeq(template).distinct().onEachIndexed { i, it ->
-      if (i < 10) {
-        println(it)
+      if (i < 100) {
+        val levAlign = levenshteinAlign(origStr, it).paintANSIColors()
+        println(levAlign)
         val pf = intGram.enumTree(it.tokenizeByWhitespace()).toList()
         println("Found " + pf.size + " parse trees")
         println(pf.first().prettyPrint())
         println("\n\n")
       }
 
+      assertTrue(levenshtein(origStr, it) <= levDist)
       assertTrue(it in gram.language)
       assertTrue(levBall.recognizes(it))
     }.toList()
@@ -238,10 +272,10 @@ class BarHillelTest {
   }
 
 /*
-./gradlew jvmTest --tests "ai.hypergraph.kaliningraph.parsing.BarHillelTest.realisticTest"
+./gradlew jvmTest --tests "ai.hypergraph.kaliningraph.parsing.BarHillelTest.semiRealisticTest"
 */
 //  @Test
-  fun realisticTest() {
+  fun semiRealisticTest() {
     val gram = Grammars.seq2parsePythonCFG.noEpsilonOrNonterminalStubs
     val toRepair = "NAME = NAME . NAME ( [ NUMBER , NUMBER , NUMBER ]".tokenizeByWhitespace()
     val levBall = makeLevFSA(toRepair, 1, gram.terminals)
diff --git a/src/commonTest/kotlin/ai/hypergraph/kaliningraph/parsing/Grammars.kt b/src/commonTest/kotlin/ai/hypergraph/kaliningraph/parsing/Grammars.kt
index d340d196..1df5673e 100644
--- a/src/commonTest/kotlin/ai/hypergraph/kaliningraph/parsing/Grammars.kt
+++ b/src/commonTest/kotlin/ai/hypergraph/kaliningraph/parsing/Grammars.kt
@@ -2,7 +2,7 @@ import ai.hypergraph.kaliningraph.parsing.*
 
 object Grammars {
   val sss = """START -> b | START | START START | START START START"""
-    .trimIndent().parseCFG().noNonterminalStubs
+    .parseCFG().noNonterminalStubs
 
   val ifThen = """
      START -> X
@@ -17,13 +17,13 @@ object Grammars {
      B -> true | false | B BO B | ( B ) | BF | N B
     BO -> and | or | xor | nand
      N -> !
-  """.trimIndent().parseCFG().noNonterminalStubs
+  """.parseCFG().noNonterminalStubs
 
   val toyArith = """
     S -> S + S | S * S | S - S | S / S | ( S ) | - S
     S -> 0 | 1 | 2 | 3 | 4
     S -> X | Y | Z
-  """.trimIndent().parseCFG().noNonterminalStubs
+  """.parseCFG().noNonterminalStubs
 
   val ocamlCFG = """
     S -> X
@@ -50,198 +50,215 @@ object Grammars {
     VO -> = | < | `||` | `&&`
     I -> 0 | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9
     B ->  true | false
-  """.trimIndent().parseCFG().noNonterminalStubs
-
-    val seq2parsePythonCFG: CFG = """
-  START -> Stmts_Or_Newlines
-  Stmts_Or_Newlines -> Stmt_Or_Newline | Stmt_Or_Newline Stmts_Or_Newlines
-  Stmt_Or_Newline -> Stmt | Newline
-
-  Newline -> NEWLINE
-
-  Async_Funcdef -> Async_Keyword Funcdef
-  Funcdef -> Def_Keyword Simple_Name Parameters Colon Suite | Def_Keyword Simple_Name Parameters Arrow Test Colon Suite
-
-  Parameters -> Open_Paren Close_Paren | Open_Paren Typedargslist Close_Paren
-  Typedargslist -> Many_Tfpdef | Many_Tfpdef Comma | Many_Tfpdef Comma Star_Double_Star_Typed | Many_Tfpdef Comma Double_Star_Tfpdef | Star_Double_Star_Typed | Double_Star_Tfpdef
-  Star_Double_Star_Typed -> Star_Tfpdef | Star_Tfpdef Comma | Star_Tfpdef Comma Double_Star_Tfpdef
-  Star_Tfpdef_Comma -> Comma Tfpdef_Default | Comma Tfpdef_Default Star_Tfpdef_Comma
-  Star_Tfpdef -> Star_Op | Star_Op Star_Tfpdef_Comma | Star_Op Tfpdef | Star_Op Tfpdef Star_Tfpdef_Comma
-  Double_Star_Tfpdef -> Double_Star_Op Tfpdef | Double_Star_Op Tfpdef Comma
-  Many_Tfpdef -> Tfpdef_Default | Tfpdef_Default Comma Many_Tfpdef
-  Tfpdef_Default -> Tfpdef | Tfpdef Assign_Op Test
-
-  Varargslist -> Many_Vfpdef | Many_Vfpdef Comma | Many_Vfpdef Comma Star_Double_Star | Many_Vfpdef Comma Double_Star_Vfpdef | Star_Double_Star | Double_Star_Vfpdef
-  Star_Double_Star -> Star_Vfpdef | Star_Vfpdef Comma | Star_Vfpdef Comma Double_Star_Vfpdef
-  Star_Vfpdef_Comma -> Comma Vfpdef_Default | Comma Vfpdef_Default Star_Vfpdef_Comma
-  Star_Vfpdef -> Star_Op | Star_Op Star_Vfpdef_Comma | Star_Op Vfpdef | Star_Op Vfpdef Star_Vfpdef_Comma
-  Double_Star_Vfpdef -> Double_Star_Op Vfpdef | Double_Star_Op Vfpdef Comma
-  Many_Vfpdef -> Vfpdef_Default | Vfpdef_Default Comma Many_Vfpdef
-  Vfpdef_Default -> Vfpdef | Vfpdef Assign_Op Test
-
-  Tfpdef -> Vfpdef | Vfpdef Colon Test
-  Vfpdef -> NAME
-  Assign_Op -> =
-  Star_Op -> *
-  Double_Star_Op -> **
-  Arrow -> arrow
-
-  Stmt -> Simple_Stmt | Compound_Stmt
-  Simple_Stmt -> Small_Stmts Newline | Small_Stmts Semicolon Newline
-  Small_Stmts -> Small_Stmt | Small_Stmt Semicolon Small_Stmts
-  Small_Stmt -> Expr_Stmt | Del_Stmt | Pass_Stmt | Flow_Stmt | Import_Stmt | Global_Stmt | Nonlocal_Stmt | Assert_Stmt
-  Expr_Stmt -> Testlist_Star_Expr Annotated_Assign | Testlist_Star_Expr Aug_Assign Yield_Expr | Testlist_Star_Expr Aug_Assign Testlist_Endcomma | Testlist_Star_Exprs_Assign
-  Annotated_Assign -> Colon Test | Colon Test Assign_Op Test
-  Test_Or_Star_Expr -> Test | Star_Expr
-  Test_Or_Star_Exprs -> Test_Or_Star_Expr | Test_Or_Star_Expr Comma Test_Or_Star_Exprs
-  Testlist_Star_Expr -> Test_Or_Star_Exprs | Test_Or_Star_Exprs Comma
-  Yield_Testlist_Star_Assign_Exprs -> Assign_Op Yield_Expr | Assign_Op Testlist_Star_Expr | Assign_Op Yield_Expr Yield_Testlist_Star_Assign_Exprs | Assign_Op Testlist_Star_Expr Yield_Testlist_Star_Assign_Exprs
-  Testlist_Star_Exprs_Assign -> Testlist_Star_Expr | Testlist_Star_Expr Yield_Testlist_Star_Assign_Exprs
-  Del_Stmt -> Del_Keyword Exprlist
-  Flow_Stmt -> Break_Stmt | Continue_Stmt | Return_Stmt | Raise_Stmt | Yield_Stmt
-  Return_Stmt -> Return_Keyword | Return_Keyword Testlist_Endcomma
-  Yield_Stmt -> Yield_Expr
-  Raise_Stmt -> Raise_Keyword | Raise_Keyword Test | Raise_Keyword Test From_Keyword Test
-  Import_Stmt -> Import_name | Import_From
-  Import_name -> Import_Keyword Dotted_As_Names
-  Dots_Plus -> Dot_Or_Dots | Dot_Or_Dots Dots_Plus
-  Start_Dotted_Name -> Dotted_Name | Dots_Plus Dotted_Name
-  Import_From_Froms -> From_Keyword Start_Dotted_Name | From_Keyword Dots_Plus
-  Import_From_Imports -> Import_Keyword Star_Op | Import_Keyword Open_Paren Import_As_Names_Endcomma Close_Paren | Import_Keyword Import_As_Names_Endcomma
-  Import_From -> Import_From_Froms Import_From_Imports
-  Import_As_Name -> Simple_Name | Simple_Name As_Keyword Simple_Name
-  Dotted_As_Name -> Dotted_Name | Dotted_Name As_Keyword Simple_Name
-  Import_As_Names -> Import_As_Name | Import_As_Name Comma Import_As_Names_Endcomma
-  Import_As_Names_Endcomma -> Import_As_Names | Import_As_Name Comma
-  Dotted_As_Names -> Dotted_As_Name | Dotted_As_Name Comma Dotted_As_Names
-  Dotted_Name -> Simple_Name | Simple_Name Dot Dotted_Name
-  Many_Names -> Simple_Name | Simple_Name Comma Many_Names
-  Global_Stmt -> Global_Keyword Many_Names
-  Nonlocal_Stmt -> Nonlocal_Keyword Many_Names
-  Assert_Stmt -> Assert_Keyword Test | Assert_Keyword Test Comma Test
-
-  Aug_Assign -> += | -= | *= | @= | /= | %= | &= | |= | ^= | <<= | >>= | **= | //=
-  Del_Keyword -> del
-  Pass_Stmt -> pass
-  Break_Stmt -> break
-  Continue_Stmt -> continue
-  Return_Keyword -> return
-  Yield_Keyword -> yield
-  Raise_Keyword -> raise
-  From_Keyword -> from
-  Import_Keyword -> import
-  Dot_Or_Dots -> . | ...
-  As_Keyword -> as
-  Global_Keyword -> global
-  Nonlocal_Keyword -> nonlocal
-  Assert_Keyword -> assert
-  Def_Keyword -> def
-  Class_Keyword -> class
-
-  Compound_Stmt -> If_Stmt | While_Stmt | For_Stmt | Try_Stmt | With_Stmt | Funcdef | Classdef | Async_Stmt
-  Async_Stmt -> Async_Keyword Funcdef | Async_Keyword With_Stmt | Async_Keyword For_Stmt
-  Elif_Stmt -> Elif_Keyword Test Colon Suite | Elif_Keyword Test Colon Suite Elif_Stmt
-  Else_Stmt -> Else_Keyword Colon Suite
-  If_Stmt -> If_Keyword Test Colon Suite | If_Keyword Test Colon Suite Else_Stmt | If_Keyword Test Colon Suite Elif_Stmt | If_Keyword Test Colon Suite Elif_Stmt Else_Stmt
-  While_Stmt -> While_Keyword Test Colon Suite | While_Keyword Test Colon Suite Else_Stmt
-  For_Stmt -> For_Keyword Exprlist In_Keyword Testlist_Endcomma Colon Suite | For_Keyword Exprlist In_Keyword Testlist_Endcomma Colon Suite Else_Stmt
-  Finally_Stmt -> Finally_Keyword Colon Suite
-  Except_Stmt -> Except_Clause Colon Suite | Except_Clause Colon Suite Except_Stmt
-  Try_Stmt -> Try_Keyword Colon Suite Finally_Stmt | Try_Keyword Colon Suite Except_Stmt | Try_Keyword Colon Suite Except_Stmt Else_Stmt | Try_Keyword Colon Suite Except_Stmt Finally_Stmt | Try_Keyword Colon Suite Except_Stmt Else_Stmt Finally_Stmt
-  With_Stmt -> With_Keyword With_Items Colon Suite
-  With_Items -> With_Item | With_Item Comma With_Items
-  With_Item -> Test | Test As_Keyword Expr
-  Except_Clause -> Except_Keyword | Except_Keyword Test | Except_Keyword Test As_Keyword Simple_Name
-  Suite -> Simple_Stmt | Newline Indent Stmts_Or_Newlines Dedent
-
-  Async_Keyword -> async
-  Await_Keyword -> await
-  If_Keyword -> if
-  Elif_Keyword -> elif
-  Else_Keyword -> else
-  While_Keyword -> while
-  For_Keyword -> for
-  In_Keyword -> in
-  Finally_Keyword -> finally
-  Except_Keyword -> except
-  Try_Keyword -> try
-  With_Keyword -> with
-  Lambda_Keyword -> lambda
-  Indent -> INDENT
-  Dedent -> DEDENT
-  Colon -> :
-  Semicolon -> ;
-  Comma -> ,
-  Dot -> .
-  Open_Paren -> (
-  Close_Paren -> )
-  Open_Sq_Bracket -> [
-  Close_Sq_Bracket -> ]
-  Open_Curl_Bracket -> {
-  Close_Curl_Bracket -> }
-
-  Test -> Or_Test | Or_Test If_Keyword Or_Test Else_Keyword Test | Lambdef
-  Test_Nocond -> Or_Test | Lambdef_Nocond
-  Lambdef -> Lambda_Keyword Colon Test | Lambda_Keyword Varargslist Colon Test
-  Lambdef_Nocond -> Lambda_Keyword Colon Test_Nocond | Lambda_Keyword Varargslist Colon Test_Nocond
-  Or_Test -> And_Test | Or_Test Or_Bool_Op And_Test
-  And_Test -> Not_Test | And_Test And_Bool_Op Not_Test
-  Not_Test -> Not_Bool_Op Not_Test | Comparison
-  Comparison -> Expr | Comparison Comp_Op Expr
-  Star_Expr -> Star_Op Expr
-  Expr -> Xor_Expr | Expr Or_Op Xor_Expr
-  Xor_Expr -> And_Expr | Xor_Expr Xor_Op And_Expr
-  And_Expr -> Shift_Expr | And_Expr And_Op Shift_Expr
-  Shift_Expr -> Arith_Expr | Shift_Expr Shift_Op Arith_Expr
-  Arith_Expr -> Term | Arith_Expr Arith_Op Term
-  Term -> Factor | Term MulDiv_Op Factor
-  Factor -> Unary_Op Factor | Power
-  Power -> Atom_Expr | Atom_Expr Double_Star_Op Factor
-  Many_Trailers -> Trailer | Trailer Many_Trailers
-  Atom_Expr -> Atom | Atom Many_Trailers | Await_Keyword Atom | Await_Keyword Atom Many_Trailers
-  Atom -> Open_Paren Close_Paren | Open_Sq_Bracket Close_Sq_Bracket | Open_Curl_Bracket Close_Curl_Bracket | Open_Paren Yield_Expr Close_Paren | Open_Paren Testlist_Comp Close_Paren | Open_Sq_Bracket Testlist_Comp Close_Sq_Bracket | Open_Curl_Bracket Dict_Or_Set_Maker Close_Curl_Bracket | Literals
-  Testlist_Comp -> Test_Or_Star_Expr Comp_For | Testlist_Star_Expr
-  Trailer -> Open_Paren Close_Paren | Open_Paren Arglist Close_Paren | Open_Sq_Bracket Subscriptlist Close_Sq_Bracket | Dot Simple_Name
-  Subscripts -> Subscript | Subscript Comma Subscripts
-  Subscriptlist -> Subscripts | Subscripts Comma
-  Subscript -> Test | Colon | Test Colon | Colon Test | Colon Sliceop | Test Colon Test | Colon Test Sliceop | Test Colon Sliceop | Test Colon Test Sliceop
-  Sliceop -> Colon | Colon Test
-  Generic_Expr -> Expr | Star_Expr
-  Generic_Exprs -> Generic_Expr | Generic_Expr Comma Generic_Exprs
-  Exprlist -> Generic_Exprs | Generic_Exprs Comma
-  Testlist -> Test | Test Comma Testlist_Endcomma
-  Testlist_Endcomma -> Testlist | Test Comma
-  KeyVal_Or_Unpack -> Test Colon Test | Double_Star_Op Expr
-  Many_KeyVals_Or_Unpacks -> KeyVal_Or_Unpack | KeyVal_Or_Unpack Comma Many_KeyVals_Or_Unpacks
-  KeyVal_Or_Unpack_Setter -> KeyVal_Or_Unpack Comp_For | Many_KeyVals_Or_Unpacks | Many_KeyVals_Or_Unpacks Comma
-  Test_Or_Star_Expr_Setter -> Test_Or_Star_Expr Comp_For | Testlist_Star_Expr
-  Dict_Or_Set_Maker -> KeyVal_Or_Unpack_Setter | Test_Or_Star_Expr_Setter
-
-  Or_Bool_Op -> or
-  And_Bool_Op -> and
-  Not_Bool_Op -> not
-  Comp_Op -> < | > | == | >= | <= | <> | != | in | not_in | is | is_not
-  Or_Op -> OR
-  Xor_Op -> ^
-  And_Op -> &
-  Shift_Op -> << | >>
-  Arith_Op -> + | -
-  MulDiv_Op -> * | @ | / | % | //
-  Unary_Op -> + | - | ~
-  Literals -> NAME | NUMBER | STRING | ... | None | True | False
-  Simple_Name -> NAME
-
-  Classdef -> Class_Keyword Simple_Name Colon Suite | Class_Keyword Simple_Name Open_Paren Close_Paren Colon Suite | Class_Keyword Simple_Name Open_Paren Arglist Close_Paren Colon Suite
-
-  Arglist -> Arguments | Arguments Comma
-  Arguments -> Argument | Argument Comma Arguments
-  Argument -> Test | Test Comp_For | Test Assign_Op Test | Double_Star_Op Test | Star_Op Test
-
-  Comp_Iter -> Comp_For | Comp_If
-  Comp_For -> For_Keyword Exprlist In_Keyword Or_Test | For_Keyword Exprlist In_Keyword Or_Test Comp_Iter | Async_Keyword For_Keyword Exprlist In_Keyword Or_Test | Async_Keyword For_Keyword Exprlist In_Keyword Or_Test Comp_Iter
-  Comp_If -> If_Keyword Test_Nocond | If_Keyword Test_Nocond Comp_Iter
-
-  Yield_Expr -> Yield_Keyword | Yield_Keyword Yield_Arg
-  Yield_Arg -> From_Keyword Test | Testlist_Endcomma 
+  """.parseCFG().noNonterminalStubs
+
+  val coarsenedPythonCFG = """
+    S -> w | S ( S ) | ( ) | S = S | S . S | S S | ( S ) | [ S ] | { S } | : | * S | [ ]
+    S -> S , S | S ; S | S : S
+    S -> S IOP S | S BOP S
+    IOP -> + | - | * | / | % | ** | << | >> | & | ^
+    BOP -> < | > | <= | >= | == | != | in | is | not in | is not
+    S -> S ;
+    S -> S | S : | - S
+    S -> None | True | False
+    S -> S ^ S | S in S
+    S -> [ S : ]
+    S -> S for S in S | S for S in S if S
+    S -> if S | if S else S | return S
+    S -> not S | S or S
+    S -> lambda w : S | lambda w , w : S | lambda w , w , w : S | lambda w , w , w , w : S
+  """.parseCFG().noNonterminalStubs
+
+  val seq2parsePythonCFG: CFG = """
+    START -> Stmts_Or_Newlines
+    Stmts_Or_Newlines -> Stmt_Or_Newline | Stmt_Or_Newline Stmts_Or_Newlines
+    Stmt_Or_Newline -> Stmt | Newline
+
+    Newline -> NEWLINE
+
+    Async_Funcdef -> Async_Keyword Funcdef
+    Funcdef -> Def_Keyword Simple_Name Parameters Colon Suite | Def_Keyword Simple_Name Parameters Arrow Test Colon Suite
+
+    Parameters -> Open_Paren Close_Paren | Open_Paren Typedargslist Close_Paren
+    Typedargslist -> Many_Tfpdef | Many_Tfpdef Comma | Many_Tfpdef Comma Star_Double_Star_Typed | Many_Tfpdef Comma Double_Star_Tfpdef | Star_Double_Star_Typed | Double_Star_Tfpdef
+    Star_Double_Star_Typed -> Star_Tfpdef | Star_Tfpdef Comma | Star_Tfpdef Comma Double_Star_Tfpdef
+    Star_Tfpdef_Comma -> Comma Tfpdef_Default | Comma Tfpdef_Default Star_Tfpdef_Comma
+    Star_Tfpdef -> Star_Op | Star_Op Star_Tfpdef_Comma | Star_Op Tfpdef | Star_Op Tfpdef Star_Tfpdef_Comma
+    Double_Star_Tfpdef -> Double_Star_Op Tfpdef | Double_Star_Op Tfpdef Comma
+    Many_Tfpdef -> Tfpdef_Default | Tfpdef_Default Comma Many_Tfpdef
+    Tfpdef_Default -> Tfpdef | Tfpdef Assign_Op Test
+
+    Varargslist -> Many_Vfpdef | Many_Vfpdef Comma | Many_Vfpdef Comma Star_Double_Star | Many_Vfpdef Comma Double_Star_Vfpdef | Star_Double_Star | Double_Star_Vfpdef
+    Star_Double_Star -> Star_Vfpdef | Star_Vfpdef Comma | Star_Vfpdef Comma Double_Star_Vfpdef
+    Star_Vfpdef_Comma -> Comma Vfpdef_Default | Comma Vfpdef_Default Star_Vfpdef_Comma
+    Star_Vfpdef -> Star_Op | Star_Op Star_Vfpdef_Comma | Star_Op Vfpdef | Star_Op Vfpdef Star_Vfpdef_Comma
+    Double_Star_Vfpdef -> Double_Star_Op Vfpdef | Double_Star_Op Vfpdef Comma
+    Many_Vfpdef -> Vfpdef_Default | Vfpdef_Default Comma Many_Vfpdef
+    Vfpdef_Default -> Vfpdef | Vfpdef Assign_Op Test
+
+    Tfpdef -> Vfpdef | Vfpdef Colon Test
+    Vfpdef -> NAME
+    Assign_Op -> =
+    Star_Op -> *
+    Double_Star_Op -> **
+    Arrow -> arrow
+
+    Stmt -> Simple_Stmt | Compound_Stmt
+    Simple_Stmt -> Small_Stmts Newline | Small_Stmts Semicolon Newline
+    Small_Stmts -> Small_Stmt | Small_Stmt Semicolon Small_Stmts
+    Small_Stmt -> Expr_Stmt | Del_Stmt | Pass_Stmt | Flow_Stmt | Import_Stmt | Global_Stmt | Nonlocal_Stmt | Assert_Stmt
+    Expr_Stmt -> Testlist_Star_Expr Annotated_Assign | Testlist_Star_Expr Aug_Assign Yield_Expr | Testlist_Star_Expr Aug_Assign Testlist_Endcomma | Testlist_Star_Exprs_Assign
+    Annotated_Assign -> Colon Test | Colon Test Assign_Op Test
+    Test_Or_Star_Expr -> Test | Star_Expr
+    Test_Or_Star_Exprs -> Test_Or_Star_Expr | Test_Or_Star_Expr Comma Test_Or_Star_Exprs
+    Testlist_Star_Expr -> Test_Or_Star_Exprs | Test_Or_Star_Exprs Comma
+    Yield_Testlist_Star_Assign_Exprs -> Assign_Op Yield_Expr | Assign_Op Testlist_Star_Expr | Assign_Op Yield_Expr Yield_Testlist_Star_Assign_Exprs | Assign_Op Testlist_Star_Expr Yield_Testlist_Star_Assign_Exprs
+    Testlist_Star_Exprs_Assign -> Testlist_Star_Expr | Testlist_Star_Expr Yield_Testlist_Star_Assign_Exprs
+    Del_Stmt -> Del_Keyword Exprlist
+    Flow_Stmt -> Break_Stmt | Continue_Stmt | Return_Stmt | Raise_Stmt | Yield_Stmt
+    Return_Stmt -> Return_Keyword | Return_Keyword Testlist_Endcomma
+    Yield_Stmt -> Yield_Expr
+    Raise_Stmt -> Raise_Keyword | Raise_Keyword Test | Raise_Keyword Test From_Keyword Test
+    Import_Stmt -> Import_name | Import_From
+    Import_name -> Import_Keyword Dotted_As_Names
+    Dots_Plus -> Dot_Or_Dots | Dot_Or_Dots Dots_Plus
+    Start_Dotted_Name -> Dotted_Name | Dots_Plus Dotted_Name
+    Import_From_Froms -> From_Keyword Start_Dotted_Name | From_Keyword Dots_Plus
+    Import_From_Imports -> Import_Keyword Star_Op | Import_Keyword Open_Paren Import_As_Names_Endcomma Close_Paren | Import_Keyword Import_As_Names_Endcomma
+    Import_From -> Import_From_Froms Import_From_Imports
+    Import_As_Name -> Simple_Name | Simple_Name As_Keyword Simple_Name
+    Dotted_As_Name -> Dotted_Name | Dotted_Name As_Keyword Simple_Name
+    Import_As_Names -> Import_As_Name | Import_As_Name Comma Import_As_Names_Endcomma
+    Import_As_Names_Endcomma -> Import_As_Names | Import_As_Name Comma
+    Dotted_As_Names -> Dotted_As_Name | Dotted_As_Name Comma Dotted_As_Names
+    Dotted_Name -> Simple_Name | Simple_Name Dot Dotted_Name
+    Many_Names -> Simple_Name | Simple_Name Comma Many_Names
+    Global_Stmt -> Global_Keyword Many_Names
+    Nonlocal_Stmt -> Nonlocal_Keyword Many_Names
+    Assert_Stmt -> Assert_Keyword Test | Assert_Keyword Test Comma Test
+
+    Aug_Assign -> += | -= | *= | @= | /= | %= | &= | |= | ^= | <<= | >>= | **= | //=
+    Del_Keyword -> del
+    Pass_Stmt -> pass
+    Break_Stmt -> break
+    Continue_Stmt -> continue
+    Return_Keyword -> return
+    Yield_Keyword -> yield
+    Raise_Keyword -> raise
+    From_Keyword -> from
+    Import_Keyword -> import
+    Dot_Or_Dots -> . | ...
+    As_Keyword -> as
+    Global_Keyword -> global
+    Nonlocal_Keyword -> nonlocal
+    Assert_Keyword -> assert
+    Def_Keyword -> def
+    Class_Keyword -> class
+
+    Compound_Stmt -> If_Stmt | While_Stmt | For_Stmt | Try_Stmt | With_Stmt | Funcdef | Classdef | Async_Stmt
+    Async_Stmt -> Async_Keyword Funcdef | Async_Keyword With_Stmt | Async_Keyword For_Stmt
+    Elif_Stmt -> Elif_Keyword Test Colon Suite | Elif_Keyword Test Colon Suite Elif_Stmt
+    Else_Stmt -> Else_Keyword Colon Suite
+    If_Stmt -> If_Keyword Test Colon Suite | If_Keyword Test Colon Suite Else_Stmt | If_Keyword Test Colon Suite Elif_Stmt | If_Keyword Test Colon Suite Elif_Stmt Else_Stmt
+    While_Stmt -> While_Keyword Test Colon Suite | While_Keyword Test Colon Suite Else_Stmt
+    For_Stmt -> For_Keyword Exprlist In_Keyword Testlist_Endcomma Colon Suite | For_Keyword Exprlist In_Keyword Testlist_Endcomma Colon Suite Else_Stmt
+    Finally_Stmt -> Finally_Keyword Colon Suite
+    Except_Stmt -> Except_Clause Colon Suite | Except_Clause Colon Suite Except_Stmt
+    Try_Stmt -> Try_Keyword Colon Suite Finally_Stmt | Try_Keyword Colon Suite Except_Stmt | Try_Keyword Colon Suite Except_Stmt Else_Stmt | Try_Keyword Colon Suite Except_Stmt Finally_Stmt | Try_Keyword Colon Suite Except_Stmt Else_Stmt Finally_Stmt
+    With_Stmt -> With_Keyword With_Items Colon Suite
+    With_Items -> With_Item | With_Item Comma With_Items
+    With_Item -> Test | Test As_Keyword Expr
+    Except_Clause -> Except_Keyword | Except_Keyword Test | Except_Keyword Test As_Keyword Simple_Name
+    Suite -> Simple_Stmt | Newline Indent Stmts_Or_Newlines Dedent
+
+    Async_Keyword -> async
+    Await_Keyword -> await
+    If_Keyword -> if
+    Elif_Keyword -> elif
+    Else_Keyword -> else
+    While_Keyword -> while
+    For_Keyword -> for
+    In_Keyword -> in
+    Finally_Keyword -> finally
+    Except_Keyword -> except
+    Try_Keyword -> try
+    With_Keyword -> with
+    Lambda_Keyword -> lambda
+    Indent -> INDENT
+    Dedent -> DEDENT
+    Colon -> :
+    Semicolon -> ;
+    Comma -> ,
+    Dot -> .
+    Open_Paren -> (
+    Close_Paren -> )
+    Open_Sq_Bracket -> [
+    Close_Sq_Bracket -> ]
+    Open_Curl_Bracket -> {
+    Close_Curl_Bracket -> }
+
+    Test -> Or_Test | Or_Test If_Keyword Or_Test Else_Keyword Test | Lambdef
+    Test_Nocond -> Or_Test | Lambdef_Nocond
+    Lambdef -> Lambda_Keyword Colon Test | Lambda_Keyword Varargslist Colon Test
+    Lambdef_Nocond -> Lambda_Keyword Colon Test_Nocond | Lambda_Keyword Varargslist Colon Test_Nocond
+    Or_Test -> And_Test | Or_Test Or_Bool_Op And_Test
+    And_Test -> Not_Test | And_Test And_Bool_Op Not_Test
+    Not_Test -> Not_Bool_Op Not_Test | Comparison
+    Comparison -> Expr | Comparison Comp_Op Expr
+    Star_Expr -> Star_Op Expr
+    Expr -> Xor_Expr | Expr Or_Op Xor_Expr
+    Xor_Expr -> And_Expr | Xor_Expr Xor_Op And_Expr
+    And_Expr -> Shift_Expr | And_Expr And_Op Shift_Expr
+    Shift_Expr -> Arith_Expr | Shift_Expr Shift_Op Arith_Expr
+    Arith_Expr -> Term | Arith_Expr Arith_Op Term
+    Term -> Factor | Term MulDiv_Op Factor
+    Factor -> Unary_Op Factor | Power
+    Power -> Atom_Expr | Atom_Expr Double_Star_Op Factor
+    Many_Trailers -> Trailer | Trailer Many_Trailers
+    Atom_Expr -> Atom | Atom Many_Trailers | Await_Keyword Atom | Await_Keyword Atom Many_Trailers
+    Atom -> Open_Paren Close_Paren | Open_Sq_Bracket Close_Sq_Bracket | Open_Curl_Bracket Close_Curl_Bracket | Open_Paren Yield_Expr Close_Paren | Open_Paren Testlist_Comp Close_Paren | Open_Sq_Bracket Testlist_Comp Close_Sq_Bracket | Open_Curl_Bracket Dict_Or_Set_Maker Close_Curl_Bracket | Literals
+    Testlist_Comp -> Test_Or_Star_Expr Comp_For | Testlist_Star_Expr
+    Trailer -> Open_Paren Close_Paren | Open_Paren Arglist Close_Paren | Open_Sq_Bracket Subscriptlist Close_Sq_Bracket | Dot Simple_Name
+    Subscripts -> Subscript | Subscript Comma Subscripts
+    Subscriptlist -> Subscripts | Subscripts Comma
+    Subscript -> Test | Colon | Test Colon | Colon Test | Colon Sliceop | Test Colon Test | Colon Test Sliceop | Test Colon Sliceop | Test Colon Test Sliceop
+    Sliceop -> Colon | Colon Test
+    Generic_Expr -> Expr | Star_Expr
+    Generic_Exprs -> Generic_Expr | Generic_Expr Comma Generic_Exprs
+    Exprlist -> Generic_Exprs | Generic_Exprs Comma
+    Testlist -> Test | Test Comma Testlist_Endcomma
+    Testlist_Endcomma -> Testlist | Test Comma
+    KeyVal_Or_Unpack -> Test Colon Test | Double_Star_Op Expr
+    Many_KeyVals_Or_Unpacks -> KeyVal_Or_Unpack | KeyVal_Or_Unpack Comma Many_KeyVals_Or_Unpacks
+    KeyVal_Or_Unpack_Setter -> KeyVal_Or_Unpack Comp_For | Many_KeyVals_Or_Unpacks | Many_KeyVals_Or_Unpacks Comma
+    Test_Or_Star_Expr_Setter -> Test_Or_Star_Expr Comp_For | Testlist_Star_Expr
+    Dict_Or_Set_Maker -> KeyVal_Or_Unpack_Setter | Test_Or_Star_Expr_Setter
+
+    Or_Bool_Op -> or
+    And_Bool_Op -> and
+    Not_Bool_Op -> not
+    Comp_Op -> < | > | == | >= | <= | <> | != | in | not_in | is | is_not
+    Or_Op -> OR
+    Xor_Op -> ^
+    And_Op -> &
+    Shift_Op -> << | >>
+    Arith_Op -> + | -
+    MulDiv_Op -> * | @ | / | % | //
+    Unary_Op -> + | - | ~
+    Literals -> NAME | NUMBER | STRING | ... | None | True | False
+    Simple_Name -> NAME
+
+    Classdef -> Class_Keyword Simple_Name Colon Suite | Class_Keyword Simple_Name Open_Paren Close_Paren Colon Suite | Class_Keyword Simple_Name Open_Paren Arglist Close_Paren Colon Suite
+
+    Arglist -> Arguments | Arguments Comma
+    Arguments -> Argument | Argument Comma Arguments
+    Argument -> Test | Test Comp_For | Test Assign_Op Test | Double_Star_Op Test | Star_Op Test
+
+    Comp_Iter -> Comp_For | Comp_If
+    Comp_For -> For_Keyword Exprlist In_Keyword Or_Test | For_Keyword Exprlist In_Keyword Or_Test Comp_Iter | Async_Keyword For_Keyword Exprlist In_Keyword Or_Test | Async_Keyword For_Keyword Exprlist In_Keyword Or_Test Comp_Iter
+    Comp_If -> If_Keyword Test_Nocond | If_Keyword Test_Nocond Comp_Iter
+
+    Yield_Expr -> Yield_Keyword | Yield_Keyword Yield_Arg
+    Yield_Arg -> From_Keyword Test | Testlist_Endcomma 
   """.parseCFG().noNonterminalStubs
 }
\ No newline at end of file