diff --git a/Tools/peg_generator/Makefile b/Tools/peg_generator/Makefile
index fb727c048b3..6ad9c91b985 100644
--- a/Tools/peg_generator/Makefile
+++ b/Tools/peg_generator/Makefile
@@ -22,7 +22,7 @@ data/xxl.py:
 
 build: peg_extension/parse.c
 
-peg_extension/parse.c: $(GRAMMAR) $(TOKENS) pegen/*.py peg_extension/peg_extension.c ../../Parser/pegen/pegen.c ../../Parser/pegen/parse_string.c ../../Parser/pegen/*.h pegen/grammar_parser.py
+peg_extension/parse.c: $(GRAMMAR) $(TOKENS) pegen/*.py peg_extension/peg_extension.c ../../Parser/pegen.c ../../Parser/string_parser.c ../../Parser/*.h pegen/grammar_parser.py
 	$(PYTHON) -m pegen -q c $(GRAMMAR) $(TOKENS) -o peg_extension/parse.c --compile-extension
 
 clean:
@@ -70,18 +70,10 @@ stats: peg_extension/parse.c data/xxl.py
 time: time_compile
 
 time_compile: venv data/xxl.py
-	$(VENVPYTHON) scripts/benchmark.py --parser=new --target=xxl compile
+	$(VENVPYTHON) scripts/benchmark.py --target=xxl compile
 
 time_parse: venv data/xxl.py
-	$(VENVPYTHON) scripts/benchmark.py --parser=new --target=xxl parse
-
-time_old: time_old_compile
-
-time_old_compile: venv data/xxl.py
-	$(VENVPYTHON) scripts/benchmark.py --parser=old --target=xxl compile
-
-time_old_parse: venv data/xxl.py
-	$(VENVPYTHON) scripts/benchmark.py --parser=old --target=xxl parse
+	$(VENVPYTHON) scripts/benchmark.py --target=xxl parse
 
 time_peg_dir: venv
 	$(VENVPYTHON) scripts/test_parse_directory.py \
diff --git a/Tools/peg_generator/pegen/keywordgen.py b/Tools/peg_generator/pegen/keywordgen.py
index 279c34b6dae..86849440966 100644
--- a/Tools/peg_generator/pegen/keywordgen.py
+++ b/Tools/peg_generator/pegen/keywordgen.py
@@ -41,9 +41,7 @@ def main():
         "grammar", type=str, help="The file with the grammar definition in PEG format"
     )
     parser.add_argument(
-        "tokens_file",
-        type=argparse.FileType("r"),
-        help="The file with the token definitions"
+        "tokens_file", type=argparse.FileType("r"), help="The file with the token definitions"
     )
     parser.add_argument(
         "keyword_file",
@@ -61,9 +59,7 @@ def main():
     gen.collect_todo()
 
     with args.keyword_file as thefile:
-        all_keywords = sorted(
-            list(gen.callmakervisitor.keyword_cache.keys()) + EXTRA_KEYWORDS
-        )
+        all_keywords = sorted(list(gen.callmakervisitor.keyword_cache.keys()) + EXTRA_KEYWORDS)
 
         keywords = ",\n    ".join(map(repr, all_keywords))
         thefile.write(TEMPLATE.format(keywords=keywords))
diff --git a/Tools/peg_generator/scripts/benchmark.py b/Tools/peg_generator/scripts/benchmark.py
index af356bed783..5fbedaa3b0e 100644
--- a/Tools/peg_generator/scripts/benchmark.py
+++ b/Tools/peg_generator/scripts/benchmark.py
@@ -6,13 +6,13 @@
 import os
 from time import time
 
-import _peg_parser
-
 try:
     import memory_profiler
 except ModuleNotFoundError:
-    print("Please run `make venv` to create a virtual environment and install"
-          " all the dependencies, before running this script.")
+    print(
+        "Please run `make venv` to create a virtual environment and install"
+        " all the dependencies, before running this script."
+    )
     sys.exit(1)
 
 sys.path.insert(0, os.getcwd())
@@ -21,13 +21,6 @@
 argparser = argparse.ArgumentParser(
     prog="benchmark", description="Reproduce the various pegen benchmarks"
 )
-argparser.add_argument(
-    "--parser",
-    action="store",
-    choices=["new", "old"],
-    default="pegen",
-    help="Which parser to benchmark (default is pegen)",
-)
 argparser.add_argument(
     "--target",
     action="store",
@@ -40,12 +33,7 @@
 command_compile = subcommands.add_parser(
     "compile", help="Benchmark parsing and compiling to bytecode"
 )
-command_parse = subcommands.add_parser(
-    "parse", help="Benchmark parsing and generating an ast.AST"
-)
-command_notree = subcommands.add_parser(
-    "notree", help="Benchmark parsing and dumping the tree"
-)
+command_parse = subcommands.add_parser("parse", help="Benchmark parsing and generating an ast.AST")
 
 
 def benchmark(func):
@@ -66,59 +54,37 @@ def wrapper(*args):
 
 
 @benchmark
-def time_compile(source, parser):
-    if parser == "old":
-        return _peg_parser.compile_string(
-            source,
-            oldparser=True,
-        )
-    else:
-        return _peg_parser.compile_string(source)
+def time_compile(source):
+    return compile(source, "<string>", "exec")
 
 
 @benchmark
-def time_parse(source, parser):
-    if parser == "old":
-        return _peg_parser.parse_string(source, oldparser=True)
-    else:
-        return _peg_parser.parse_string(source)
+def time_parse(source):
+    return ast.parse(source)
 
 
-@benchmark
-def time_notree(source, parser):
-    if parser == "old":
-        return _peg_parser.parse_string(source, oldparser=True, ast=False)
-    else:
-        return _peg_parser.parse_string(source, ast=False)
-
-
-def run_benchmark_xxl(subcommand, parser, source):
+def run_benchmark_xxl(subcommand, source):
     if subcommand == "compile":
-        time_compile(source, parser)
+        time_compile(source)
     elif subcommand == "parse":
-        time_parse(source, parser)
-    elif subcommand == "notree":
-        time_notree(source, parser)
+        time_parse(source)
 
 
-def run_benchmark_stdlib(subcommand, parser):
-    modes = {"compile": 2, "parse": 1, "notree": 0}
+def run_benchmark_stdlib(subcommand):
+    modes = {"compile": 2, "parse": 1}
     for _ in range(3):
         parse_directory(
             "../../Lib",
             verbose=False,
             excluded_files=["*/bad*", "*/lib2to3/tests/data/*",],
-            tree_arg=0,
             short=True,
             mode=modes[subcommand],
-            oldparser=(parser == "old"),
         )
 
 
 def main():
     args = argparser.parse_args()
     subcommand = args.subcommand
-    parser = args.parser
     target = args.target
 
     if subcommand is None:
@@ -127,9 +93,9 @@ def main():
     if target == "xxl":
         with open(os.path.join("data", "xxl.py"), "r") as f:
             source = f.read()
-            run_benchmark_xxl(subcommand, parser, source)
+            run_benchmark_xxl(subcommand, source)
     elif target == "stdlib":
-        run_benchmark_stdlib(subcommand, parser)
+        run_benchmark_stdlib(subcommand)
 
 
 if __name__ == "__main__":
diff --git a/Tools/peg_generator/scripts/find_max_nesting.py b/Tools/peg_generator/scripts/find_max_nesting.py
index f2fdd00bfb7..92045c93ff7 100755
--- a/Tools/peg_generator/scripts/find_max_nesting.py
+++ b/Tools/peg_generator/scripts/find_max_nesting.py
@@ -14,8 +14,7 @@
 Usage: python -m scripts.find_max_nesting
 """
 import sys
-
-from _peg_parser import parse_string
+import ast
 
 GRAMMAR_FILE = "data/python.gram"
 INITIAL_NESTING_DEPTH = 10
@@ -28,9 +27,8 @@
 
 def check_nested_expr(nesting_depth: int) -> bool:
     expr = f"{'(' * nesting_depth}0{')' * nesting_depth}"
-
     try:
-        parse_string(expr)
+        ast.parse(expr)
         print(f"Nesting depth of {nesting_depth} is successful")
         return True
     except Exception as err:
diff --git a/Tools/peg_generator/scripts/show_parse.py b/Tools/peg_generator/scripts/show_parse.py
deleted file mode 100755
index b4ee5a1b357..00000000000
--- a/Tools/peg_generator/scripts/show_parse.py
+++ /dev/null
@@ -1,121 +0,0 @@
-#!/usr/bin/env python3.8
-
-"""Show the parse tree for a given program, nicely formatted.
-
-Example:
-
-$ scripts/show_parse.py a+b
-Module(
-    body=[
-        Expr(
-            value=BinOp(
-                left=Name(id="a", ctx=Load()), op=Add(), right=Name(id="b", ctx=Load())
-            )
-        )
-    ],
-    type_ignores=[],
-)
-$
-
-Use -v to show line numbers and column offsets.
-
-The formatting is done using black.  You can also import this module
-and call one of its functions.
-"""
-
-import argparse
-import ast
-import difflib
-import os
-import sys
-import tempfile
-
-import _peg_parser
-
-from typing import List
-
-sys.path.insert(0, os.getcwd())
-from pegen.ast_dump import ast_dump
-
-parser = argparse.ArgumentParser()
-parser.add_argument(
-    "-d", "--diff", action="store_true", help="show diff between grammar and ast (requires -g)"
-)
-parser.add_argument(
-    "-p",
-    "--parser",
-    choices=["new", "old"],
-    default="new",
-    help="choose the parser to use"
-)
-parser.add_argument(
-    "-m",
-    "--multiline",
-    action="store_true",
-    help="concatenate program arguments using newline instead of space",
-)
-parser.add_argument("-v", "--verbose", action="store_true", help="show line/column numbers")
-parser.add_argument("program", nargs="+", help="program to parse (will be concatenated)")
-
-
-def format_tree(tree: ast.AST, verbose: bool = False) -> str:
-    with tempfile.NamedTemporaryFile("w+") as tf:
-        tf.write(ast_dump(tree, include_attributes=verbose))
-        tf.write("\n")
-        tf.flush()
-        cmd = f"black -q {tf.name}"
-        sts = os.system(cmd)
-        if sts:
-            raise RuntimeError(f"Command {cmd!r} failed with status 0x{sts:x}")
-        tf.seek(0)
-        return tf.read()
-
-
-def diff_trees(a: ast.AST, b: ast.AST, verbose: bool = False) -> List[str]:
-    sa = format_tree(a, verbose)
-    sb = format_tree(b, verbose)
-    la = sa.splitlines()
-    lb = sb.splitlines()
-    return list(difflib.unified_diff(la, lb, "a", "b", lineterm=""))
-
-
-def show_parse(source: str, verbose: bool = False) -> str:
-    tree = _peg_parser.parse_string(source, oldparser=True)
-    return format_tree(tree, verbose).rstrip("\n")
-
-
-def print_parse(source: str, verbose: bool = False) -> None:
-    print(show_parse(source, verbose))
-
-
-def main() -> None:
-    args = parser.parse_args()
-    new_parser = args.parser == "new"
-    if args.multiline:
-        sep = "\n"
-    else:
-        sep = " "
-    program = sep.join(args.program)
-    if new_parser:
-        tree = _peg_parser.parse_string(program)
-
-        if args.diff:
-            a = _peg_parser.parse_string(program, oldparser=True)
-            b = tree
-            diff = diff_trees(a, b, args.verbose)
-            if diff:
-                for line in diff:
-                    print(line)
-            else:
-                print("# Trees are the same")
-        else:
-            print("# Parsed using the new parser")
-            print(format_tree(tree, args.verbose))
-    else:
-        tree = _peg_parser.parse_string(program, oldparser=True)
-        print("# Parsed using the old parser")
-        print(format_tree(tree, args.verbose))
-
-
-if __name__ == "__main__":
-    main()
diff --git a/Tools/peg_generator/scripts/test_parse_directory.py b/Tools/peg_generator/scripts/test_parse_directory.py
index 63204ce9dc1..d8f4f0ecd3e 100755
--- a/Tools/peg_generator/scripts/test_parse_directory.py
+++ b/Tools/peg_generator/scripts/test_parse_directory.py
@@ -7,7 +7,6 @@
 import time
 import traceback
 import tokenize
-import _peg_parser
 from glob import glob
 from pathlib import PurePath
 
@@ -16,7 +15,6 @@
 sys.path.insert(0, os.getcwd())
 from pegen.ast_dump import ast_dump
 from pegen.testutil import print_memstats
-from scripts import show_parse
 
 SUCCESS = "\033[92m"
 FAIL = "\033[91m"
@@ -40,9 +38,6 @@
 argparser.add_argument(
     "-v", "--verbose", action="store_true", help="Display detailed errors for failures"
 )
-argparser.add_argument(
-    "-t", "--tree", action="count", help="Compare parse tree to official AST", default=0
-)
 
 
 def report_status(
@@ -79,66 +74,13 @@ def report_status(
             print(f"  {str(error.__class__.__name__)}: {error}")
 
 
-def compare_trees(
-    actual_tree: ast.AST, file: str, verbose: bool, include_attributes: bool = False,
-) -> int:
-    with open(file) as f:
-        expected_tree = _peg_parser.parse_string(f.read(), oldparser=True)
-
-    expected_text = ast_dump(expected_tree, include_attributes=include_attributes)
-    actual_text = ast_dump(actual_tree, include_attributes=include_attributes)
-    if actual_text == expected_text:
-        if verbose:
-            print("Tree for {file}:")
-            print(show_parse.format_tree(actual_tree, include_attributes))
-        return 0
-
-    print(f"Diffing ASTs for {file} ...")
-
-    expected = show_parse.format_tree(expected_tree, include_attributes)
-    actual = show_parse.format_tree(actual_tree, include_attributes)
-
-    if verbose:
-        print("Expected for {file}:")
-        print(expected)
-        print("Actual for {file}:")
-        print(actual)
-        print(f"Diff for {file}:")
-
-    diff = show_parse.diff_trees(expected_tree, actual_tree, include_attributes)
-    for line in diff:
-        print(line)
-
-    return 1
-
-
-def parse_file(source: str, file: str, mode: int, oldparser: bool) -> Tuple[Any, float]:
+def parse_file(source: str, file: str) -> Tuple[Any, float]:
     t0 = time.time()
-    if mode == COMPILE:
-        result = _peg_parser.compile_string(
-            source,
-            filename=file,
-            oldparser=oldparser,
-        )
-    else:
-        result = _peg_parser.parse_string(
-            source,
-            filename=file,
-            oldparser=oldparser,
-            ast=(mode == PARSE),
-        )
+    result = ast.parse(source, filename=file)
     t1 = time.time()
     return result, t1 - t0
 
 
-def is_parsing_failure(source: str) -> bool:
-    try:
-        _peg_parser.parse_string(source, mode="exec", oldparser=True)
-    except SyntaxError:
-        return False
-    return True
-
-
 def generate_time_stats(files, total_seconds) -> None:
     total_files = len(files)
     total_bytes = 0
@@ -160,27 +102,11 @@ def generate_time_stats(files, total_seconds) -> None:
         )
 
 
-def parse_directory(
-    directory: str,
-    verbose: bool,
-    excluded_files: List[str],
-    tree_arg: int,
-    short: bool,
-    mode: int,
-    oldparser: bool,
-) -> int:
-    if tree_arg:
-        assert mode == PARSE, "Mode should be 1 (parse), when comparing the generated trees"
-
-    if oldparser and tree_arg:
-        print("Cannot specify tree argument with the cpython parser.", file=sys.stderr)
-        return 1
-
+def parse_directory(directory: str, verbose: bool, excluded_files: List[str], short: bool) -> int:
     # For a given directory, traverse files and attempt to parse each one
     # - Output success/failure for each file
     errors = 0
     files = []
-    trees = {}  # Trees to compare (after everything else is done)
     total_seconds = 0
 
     for file in sorted(glob(f"{directory}/**/*.py", recursive=True)):
@@ -192,39 +118,20 @@ def parse_directory(
             source = f.read()
 
         try:
-            result, dt = parse_file(source, file, mode, oldparser)
+            result, dt = parse_file(source, file)
             total_seconds += dt
-            if tree_arg:
-                trees[file] = result
             report_status(succeeded=True, file=file, verbose=verbose, short=short)
         except SyntaxError as error:
-            if is_parsing_failure(source):
-                print(f"File {file} cannot be parsed by either parser.")
-            else:
-                report_status(
-                    succeeded=False, file=file, verbose=verbose, error=error, short=short
-                )
-                errors += 1
+            report_status(succeeded=False, file=file, verbose=verbose, error=error, short=short)
+            errors += 1
         files.append(file)
 
-    t1 = time.time()
-
     generate_time_stats(files, total_seconds)
     if short:
         print_memstats()
 
     if errors:
         print(f"Encountered {errors} failures.", file=sys.stderr)
-
-    # Compare trees (the dict is empty unless -t is given)
-    compare_trees_errors = 0
-    for file, tree in trees.items():
-        if not short:
-            print("Comparing ASTs for", file)
-        if compare_trees(tree, file, verbose, tree_arg >= 2) == 1:
-            compare_trees_errors += 1
-
-    if errors or compare_trees_errors:
         return 1
 
     return 0
@@ -235,20 +142,8 @@ def main() -> None:
     directory = args.directory
     verbose = args.verbose
     excluded_files = args.exclude
-    tree = args.tree
     short = args.short
-    mode = 1 if args.tree else 2
-    sys.exit(
-        parse_directory(
-            directory,
-            verbose,
-            excluded_files,
-            tree,
-            short,
-            mode,
-            oldparser=False,
-        )
-    )
+    sys.exit(parse_directory(directory, verbose, excluded_files, short))
 
 
 if __name__ == "__main__":