verified through testing that insertion works as expected as far as contents of string is concerned. However, have added print statements which I need to remove when I have a fully working implementation

tests/compare.mlb

@@ -0,0 +1,16 @@
+$(SML_LIB)/basis/basis.mlb
+
+ann
+  "allowVectorExps true"
+in
+  ../data-sets/svelte.sml
+  (*
+  ../data-sets/rust.sml
+  ../data-sets/seph.sml
+  ../data-sets/automerge.sml
+  *)
+end
+
+../src/tiny_rope.sml
+../src/line_gap.sml
+compare_to_rope.sml

tests/compare_to_rope.sml

@@ -1,16 +1,67 @@
 structure CompareToRope =
 struct
-  local
-    fun folder ((pos, delNum, insStr), buffer, fIns, fDel) =
-      let
-        val buffer =
-          if String.size insStr > 0 then 
-            fIns (pos, insStr, buffer) else buffer
-      in
-        buffer
-      end
+fun compareTxns arr =
+  Vector.foldli
+    (fn (idx, (pos, delNum, insStr), (rope, gapBuffer)) =>
+       let
+         val _ = print ("idx: " ^ Int.toString idx ^ "\n")
+         val oldRope = rope
+         val strSize = String.size insStr
+
+         val rope =
+           if strSize > 0 then TinyRope.insert (pos, insStr, rope) else rope
+
+         val gapBuffer =
+           if strSize > 0 then LineGap.insert (pos, insStr, gapBuffer)
+           else gapBuffer
+
+         val ropeString = TinyRope.toString rope
+         val gapBufferString = LineGap.toString gapBuffer
+       in
+         if ropeString = gapBufferString then
+           (rope, gapBuffer)
+         else
+           let
+             val _ = print
+               ("difference detected at txn number: " ^ (Int.toString idx)
+                ^ "\n")
+             val txn = String.concat
+               [ "offending txn: \n"
+               , "pos: "
+               , Int.toString pos
+               , ", delNum: "
+               , Int.toString delNum
+               , ", insStr: |"
+               , insStr
+               , "|\n"
+               ]
+             val _ = print txn
+
+             val _ = print "before offending string: \n"
+             val _ = print (TinyRope.toString oldRope)
+             val _ = print "\n"
+
+             val _ = print "rope string: \n"
+             val _ = print (ropeString ^ "\n")
+             val _ = print "gap string: \n"
+             val _ = print (gapBufferString ^ "\n")
+             val _ = raise Empty
+           in
+             (rope, gapBuffer)
+           end
+       end) (TinyRope.empty, LineGap.empty) arr
+
+  fun main () =
+  let
+    val _ = compareTxns SvelteComponent.txns
+    (*
+    val _ = compareTxns Rust.txns
+    val _ = compareTxns Seph.txns
+    val _ = compareTxns Automerge.txns
+    *)
   in
-    fun runTxns () =
-      Vector.foldl folder Txn.empty Txn.txns
+    ()
   end
+
+  val _ = main ()
 end