Backport ExceptionGroup

Resolves #789.

DOCS.md

@@ -90,6 +90,7 @@ The full list of optional dependencies is:
 - `watch`: enables use of the `--watch` flag.
 - `mypy`: enables use of the `--mypy` flag.
 - `backports`: installs libraries that backport newer Python features to older versions, which Coconut will automatically use instead of the standard library if the standard library is not available. Specifically:
+  - Installs [`exceptiongroup`](https://pypi.org/project/exceptiongroup/) to backport [`ExceptionGroup` and `BaseExceptionGroup`](https://docs.python.org/3/library/exceptions.html#ExceptionGroup).
   - Installs [`dataclasses`](https://pypi.org/project/dataclasses/) to backport [`dataclasses`](https://docs.python.org/3/library/dataclasses.html).
   - Installs [`typing`](https://pypi.org/project/typing/) to backport [`typing`](https://docs.python.org/3/library/typing.html) ([`typing_extensions`](https://pypi.org/project/typing-extensions/) is always installed for backporting individual `typing` objects).
   - Installs [`aenum`](https://pypi.org/project/aenum) to backport [`enum`](https://docs.python.org/3/library/enum.html).

Makefile

@@ -52,6 +52,10 @@ setup-pypy3:
 install: setup
 	python -m pip install -e .[tests]
 
+.PHONY: install-purepy
+install-purepy: setup
+	python -m pip install --no-deps --upgrade -e . "pyparsing<3"
+
 .PHONY: install-py2
 install-py2: setup-py2
 	python2 -m pip install -e .[tests]

coconut/compiler/header.py

@@ -934,7 +934,9 @@ def getheader(which, use_hash, target, no_tco, strict, no_wrap):
         newline=True,
     ).format(**format_dict)
 
-    if target_info >= (3, 9):
+    if target_info >= (3, 11):
+        header += _get_root_header("311")
+    elif target_info >= (3, 9):
         header += _get_root_header("39")
     if target_info >= (3, 7):
         header += _get_root_header("37")

coconut/compiler/util.py

@@ -214,7 +214,7 @@ def evaluate_tokens(tokens, **kwargs):
 
 class ComputationNode(object):
     """A single node in the computation graph."""
-    __slots__ = ("action", "original", "loc", "tokens") + (("been_called",) if DEVELOP else ())
+    __slots__ = ("action", "original", "loc", "tokens")
     pprinting = False
 
     def __new__(cls, action, original, loc, tokens, ignore_no_tokens=False, ignore_one_token=False, greedy=False, trim_arity=True):
@@ -236,8 +236,6 @@ def __new__(cls, action, original, loc, tokens, ignore_no_tokens=False, ignore_o
             self.original = original
             self.loc = loc
             self.tokens = tokens
-            if DEVELOP:
-                self.been_called = False
             if greedy:
                 return self.evaluate()
             else:
@@ -253,9 +251,9 @@ def name(self):
     def evaluate(self):
         """Get the result of evaluating the computation graph at this node.
         Very performance sensitive."""
-        if DEVELOP:  # avoid the overhead of the call if not develop
-            internal_assert(not self.been_called, "inefficient reevaluation of action " + self.name + " with tokens", self.tokens)
-            self.been_called = True
+        # note that this should never cache, since if a greedy Wrap that doesn't add to the packrat context
+        #  hits the cache, it'll get the same ComputationNode object, but since it's greedy that object needs
+        #  to actually be reevaluated
         evaluated_toks = evaluate_tokens(self.tokens)
         if logger.tracing:  # avoid the overhead of the call if not tracing
             logger.log_trace(self.name, self.original, self.loc, evaluated_toks, self.tokens)

coconut/constants.py

@@ -583,7 +583,9 @@ def get_path_env_var(env_var, default):
     '__file__',
     '__annotations__',
     '__debug__',
-    # # don't include builtins that aren't always made available by Coconut:
+    # we treat these as coconut_exceptions so the highlighter will always know about them:
+    # 'ExceptionGroup', 'BaseExceptionGroup',
+    # don't include builtins that aren't always made available by Coconut:
     # 'BlockingIOError', 'ChildProcessError', 'ConnectionError',
     # 'BrokenPipeError', 'ConnectionAbortedError', 'ConnectionRefusedError',
     # 'ConnectionResetError', 'FileExistsError', 'FileNotFoundError',
@@ -807,8 +809,11 @@ def get_path_env_var(env_var, default):
 
 coconut_exceptions = (
     "MatchError",
+    "ExceptionGroup",
+    "BaseExceptionGroup",
 )
 
+highlight_builtins = coconut_specific_builtins + interp_only_builtins
 all_builtins = frozenset(python_builtins + coconut_specific_builtins + coconut_exceptions)
 
 magic_methods = (
@@ -938,6 +943,7 @@ def get_path_env_var(env_var, default):
         ("dataclasses", "py==36"),
         ("typing", "py<35"),
         ("async_generator", "py35"),
+        ("exceptiongroup", "py37"),
     ),
     "dev": (
         ("pre-commit", "py3"),
@@ -994,6 +1000,7 @@ def get_path_env_var(env_var, default):
     ("xonsh", "py38"): (0, 14),
     ("pytest", "py36"): (7,),
     ("async_generator", "py35"): (1, 10),
+    ("exceptiongroup", "py37"): (1,),
 
     # pinned reqs: (must be added to pinned_reqs below)
 

coconut/highlighter.py

@@ -25,8 +25,7 @@
 from pygments.util import shebang_matches
 
 from coconut.constants import (
-    coconut_specific_builtins,
-    interp_only_builtins,
+    highlight_builtins,
     new_operators,
     tabideal,
     default_encoding,
@@ -94,7 +93,7 @@ class CoconutLexer(Python3Lexer):
         (words(reserved_vars, prefix=r"(?<!\\):?", suffix=r"\b"), Keyword),
     ]
     tokens["builtins"] += [
-        (words(coconut_specific_builtins + interp_only_builtins, suffix=r"\b"), Name.Builtin),
+        (words(highlight_builtins, suffix=r"\b"), Name.Builtin),
         (words(coconut_exceptions, suffix=r"\b"), Name.Exception),
     ]
     tokens["numbers"] = [

coconut/root.py

@@ -26,7 +26,7 @@
 VERSION = "3.0.3"
 VERSION_NAME = None
 # False for release, int >= 1 for develop
-DEVELOP = 8
+DEVELOP = 9
 ALPHA = False  # for pre releases rather than post releases
 
 assert DEVELOP is False or DEVELOP >= 1, "DEVELOP must be False or an int >= 1"
@@ -45,6 +45,16 @@ def _indent(code, by=1, tabsize=4, strip=False, newline=False, initial_newline=F
     ) + ("\n" if newline else "")
 
 
+def _get_target_info(target):
+    """Return target information as a version tuple."""
+    if not target or target == "universal":
+        return ()
+    elif len(target) == 1:
+        return (int(target),)
+    else:
+        return (int(target[0]), int(target[1:]))
+
+
 # -----------------------------------------------------------------------------------------------------------------------
 # HEADER:
 # -----------------------------------------------------------------------------------------------------------------------
@@ -264,15 +274,24 @@ def _coconut_reduce_partial(self):
     _coconut_copy_reg.pickle(_coconut_functools.partial, _coconut_reduce_partial)
 '''
 
+_py3_before_py311_extras = '''try:
+    from exceptiongroup import ExceptionGroup, BaseExceptionGroup
+except ImportError:
+    class you_need_to_install_exceptiongroup(object):
+        __slots__ = ()
+    ExceptionGroup = BaseExceptionGroup = you_need_to_install_exceptiongroup()
+'''
+
 
 # whenever new versions are added here, header.py must be updated to use them
 ROOT_HEADER_VERSIONS = (
     "universal",
     "2",
-    "3",
     "27",
+    "3",
     "37",
     "39",
+    "311",
 )
 
 
@@ -284,6 +303,7 @@ def _get_root_header(version="universal"):
 ''' + _indent(_get_root_header("2")) + '''else:
 ''' + _indent(_get_root_header("3"))
 
+    version_info = _get_target_info(version)
     header = ""
 
     if version.startswith("3"):
@@ -293,7 +313,7 @@ def _get_root_header(version="universal"):
         # if a new assignment is added below, a new builtins import should be added alongside it
         header += _base_py2_header
 
-    if version in ("37", "39"):
+    if version_info >= (3, 7):
         header += r'''py_breakpoint = breakpoint
 '''
     elif version == "3":
@@ -311,7 +331,7 @@ def _get_root_header(version="universal"):
         header += r'''if _coconut_sys.version_info < (3, 7):
 ''' + _indent(_below_py37_extras) + r'''elif _coconut_sys.version_info < (3, 9):
 ''' + _indent(_py37_py38_extras)
-    elif version == "37":
+    elif (3, 7) <= version_info < (3, 9):
         header += r'''if _coconut_sys.version_info < (3, 9):
 ''' + _indent(_py37_py38_extras)
     elif version.startswith("2"):
@@ -320,7 +340,11 @@ def _get_root_header(version="universal"):
 dict.items = _coconut_OrderedDict.viewitems
 '''
     else:
-        assert version == "39", version
+        assert version_info >= (3, 9), version
+
+    if (3,) <= version_info < (3, 11):
+        header += r'''if _coconut_sys.version_info < (3, 11):
+''' + _indent(_py3_before_py311_extras)
 
     return header
 

coconut/tests/src/cocotest/agnostic/specific.coco

@@ -2,7 +2,7 @@ from io import StringIO
 if TYPE_CHECKING:
     from typing import Any
 
-from .util import mod  # NOQA
+from .util import mod, assert_raises  # NOQA
 
 
 def non_py26_test() -> bool:
@@ -181,6 +181,8 @@ def py37_spec_test() -> bool:
     class HasVarGen[*Ts]  # type: ignore
     assert HasVarGen `issubclass` object
     assert typing.Protocol.__module__ == "typing_extensions"
+    assert_raises((def -> raise ExceptionGroup("derp", [Exception("herp")])), ExceptionGroup)
+    assert_raises((def -> raise BaseExceptionGroup("derp", [BaseException("herp")])), BaseExceptionGroup)
     return True
 
 

coconut/util.py

@@ -39,6 +39,7 @@
     except ImportError:
         lru_cache = None
 
+from coconut.root import _get_target_info
 from coconut.constants import (
     fixpath,
     default_encoding,
@@ -265,6 +266,9 @@ def ensure_dir(dirpath):
 # -----------------------------------------------------------------------------------------------------------------------
 
 
+get_target_info = _get_target_info
+
+
 def ver_tuple_to_str(req_ver):
     """Converts a requirement version tuple into a version string."""
     return ".".join(str(x) for x in req_ver)
@@ -287,16 +291,6 @@ def get_next_version(req_ver, point_to_increment=-1):
     return req_ver[:point_to_increment] + (req_ver[point_to_increment] + 1,)
 
 
-def get_target_info(target):
-    """Return target information as a version tuple."""
-    if not target:
-        return ()
-    elif len(target) == 1:
-        return (int(target),)
-    else:
-        return (int(target[0]), int(target[1:]))
-
-
 def get_displayable_target(target):
     """Get a displayable version of the target."""
     try: