Phase 2: bump floor to Python 3.10, version to 2.0.0

Technologicat · claude · Technologicat · commit 703edd69aeb5 · 2026-03-12T10:26:07.000+02:00
Drop Python 3.8/3.9 support. Remove all dead version guards
(18 sites): ast.Index wrappers (3.9), posonlyargs hasattr checks
(3.8), CodeType positional construction (3.8), types.UnionType
guard (3.10). Include posonlyargs directly in arguments()
constructors. Remove walrus-inside-subscript parens (now 3.10+).

Update TODO comments: parenthesis syntax for macro arguments is
now deprecated; kept for backward compatibility.

Update metadata: requires-python &gt;=3.10,&lt;3.15, mcpyrate dev dep,
classifiers (drop 3.8/3.9, add 3.13/3.14, Production/Stable).
CI matrix: 3.10–3.14 + pypy-3.11. Coverage on 3.12.
Update CLAUDE.md, README.md, CONTRIBUTING.md.

Co-Authored-By: Claude Opus 4.6 &lt;noreply@anthropic.com&gt;
diff --git a/.github/workflows/coverage.yml b/.github/workflows/coverage.yml
@@ -15,7 +15,7 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        python-version: ["3.10"]
+        python-version: ["3.12"]
 
     steps:
     - uses: actions/checkout@v6
diff --git a/.github/workflows/python-package.yml b/.github/workflows/python-package.yml
@@ -17,7 +17,7 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        python-version: ["3.8", "3.9", "3.10", "3.11", "3.12", pypy-3.8, pypy-3.9, pypy-3.10]
+        python-version: ["3.10", "3.11", "3.12", "3.13", "3.14", "pypy-3.11"]
 
     steps:
     - uses: actions/checkout@v6
diff --git a/CLAUDE.md b/CLAUDE.md
@@ -12,11 +12,11 @@ A Python library providing language extensions and utilities inspired by Lisp, H
 
 ## API stability
 
-Released as 1.0.0 in February 2026, signalling API stability. The public API (everything in `__all__`) should remain backward-compatible. If backward-incompatible changes become necessary (e.g. due to Python 3.13/3.14 compat), they warrant a 2.0.0 release. Prefer non-breaking solutions when possible.
+Released as 2.0.0 in March 2026 (floor bump + mcpyrate 4.0.0 dependency). The public API (everything in `__all__`) should remain backward-compatible. Prefer non-breaking solutions when possible.
 
 ## Build and development
 
-Uses PDM with `pdm-backend`. Python 3.8–3.12, also PyPy 3.8–3.10. Version 3.13/3.14 compatibility update pending (will be released as 1.1.0).
+Uses PDM with `pdm-backend`. Python 3.10–3.14, also PyPy 3.11.
 
 ```bash
 # Set up development environment
diff --git a/CONTRIBUTING.md b/CONTRIBUTING.md
@@ -118,7 +118,7 @@ The `lazify` and `continuations` macros are the most complex (and perhaps fearso
 
 `unpythonic.syntax.scopeanalyzer` is a unfortunate artifact that is needed to implement macros that interact with Python's scoping rules, notably `let`. Fortunately, [the language reference explicitly documents](https://docs.python.org/3/reference/executionmodel.html#naming-and-binding) what is needed for a lexical scope analysis for Python. So we have just implemented that (better, as an AST analysis, rather than scanning the surface syntax text).
 
-As of the first half of 2021, the main target platforms are **CPython 3.8** and **PyPy3 3.7** (since as of April 2021, PyPy3 does not have 3.8 yet). The code should run on 3.6 or any later Python. We have [a GitHub workflow](https://github.com/Technologicat/unpythonic/actions?query=workflow%3A%22Python+package%22) that runs the test suite on CPython 3.6 through 3.9, and on PyPy3.
+As of v2.0.0, the main target platforms are **CPython 3.10** through **3.14**, and **PyPy3** (language version 3.11). We have [a GitHub workflow](https://github.com/Technologicat/unpythonic/actions?query=workflow%3A%22Python+package%22) that runs the test suite on these platforms.
 
 
 ## Style guide
diff --git a/README.md b/README.md
@@ -17,7 +17,7 @@ None required.
 
  - [`mcpyrate`](https://github.com/Technologicat/mcpyrate) optional, to enable the syntactic macro layer, an interactive macro REPL, and some example dialects.
 
-As of v0.15.3, `unpythonic` runs on CPython 3.8, 3.9 and 3.10, 3.11, 3.12, and PyPy3 (language versions 3.8, 3.9, 3.10); the [CI](https://en.wikipedia.org/wiki/Continuous_integration) process verifies the tests pass on those platforms. New Python versions are added and old ones are removed following the [Long-term support roadmap](https://github.com/Technologicat/unpythonic/issues/1).
+As of v2.0.0, `unpythonic` runs on CPython 3.10, 3.11, 3.12, 3.13, 3.14, and PyPy3 (language version 3.11); the [CI](https://en.wikipedia.org/wiki/Continuous_integration) process verifies the tests pass on those platforms. New Python versions are added and old ones are removed following the [Long-term support roadmap](https://github.com/Technologicat/unpythonic/issues/1).
 
 
 ### Documentation
diff --git a/pyproject.toml b/pyproject.toml
@@ -4,7 +4,7 @@ description = "Supercharge your Python with parts of Lisp and Haskell."
 authors = [
     { name = "Juha Jeronen", email = "juha.m.jeronen@gmail.com" },
 ]
-requires-python = ">=3.8,<3.13"
+requires-python = ">=3.10,<3.15"
 
 # the `read` function and long_description_content_type from setup.py are no longer needed,
 # modern build tools like pdm/hatch already know how to handle markdown if you point them at a .md file
@@ -19,25 +19,25 @@ license = { text = "BSD" }
 dynamic = ["version"]
 
 dependencies = [
-    "mcpyrate>=3.6.4",
+    "mcpyrate @ file:///home/jje/Documents/koodit/mcpyrate",
     "sympy>=1.13"
 ]
 keywords=["functional-programming", "language-extension", "syntactic-macros",
           "tail-call-optimization", "tco", "continuations", "currying", "lazy-evaluation",
           "dynamic-variable", "macros", "lisp", "scheme", "racket", "haskell"]
 classifiers = [
-    "Development Status :: 4 - Beta",
+    "Development Status :: 5 - Production/Stable",
     "Environment :: Console",
     "Intended Audience :: Developers",
     "License :: OSI Approved :: BSD License",
     "Operating System :: POSIX :: Linux",
     "Programming Language :: Python",
     "Programming Language :: Python :: 3",
-    "Programming Language :: Python :: 3.8",
-    "Programming Language :: Python :: 3.9",
     "Programming Language :: Python :: 3.10",
     "Programming Language :: Python :: 3.11",
     "Programming Language :: Python :: 3.12",
+    "Programming Language :: Python :: 3.13",
+    "Programming Language :: Python :: 3.14",
     "Programming Language :: Python :: Implementation :: CPython",
     "Programming Language :: Python :: Implementation :: PyPy",
     "Topic :: Software Development :: Libraries",
diff --git a/unpythonic/__init__.py b/unpythonic/__init__.py
@@ -7,7 +7,7 @@
 for a trip down the rabbit hole.
 """
 
-__version__ = '1.0.1'
+__version__ = '2.0.0'
 
 from .amb import *  # noqa: F401, F403
 from .arity import *  # noqa: F401, F403
diff --git a/unpythonic/misc.py b/unpythonic/misc.py
@@ -15,9 +15,8 @@
 from itertools import count
 import inspect
 from queue import Empty
-from sys import version_info
 from time import monotonic
-from types import CodeType, FunctionType, LambdaType
+from types import FunctionType, LambdaType
 
 from .regutil import register_decorator
 
@@ -98,27 +97,7 @@ def rename(f):
         f.__name__ = name
         idx = f.__qualname__.rfind('.')
         f.__qualname__ = f"{f.__qualname__[:idx]}.{name}" if idx != -1 else name
-        # __code__.co_name is read-only, but there's a types.CodeType constructor
-        # that we can use to re-create the code object with the new name.
-        # (This is no worse than what the stdlib's Lib/modulefinder.py already does.)
-        co = f.__code__
-        # https://github.com/ipython/ipython/blob/master/IPython/core/interactiveshell.py
-        # https://www.python.org/dev/peps/pep-0570/
-        # https://docs.python.org/3/library/types.html#types.CodeType
-        # https://docs.python.org/3/library/inspect.html#types-and-members
-        if version_info >= (3, 8, 0):  # Python 3.8+: positional-only parameters
-            # In Python 3.8+, `CodeType` has the convenient `replace()` method to functionally update it.
-            # In Python 3.10, we must actually use it to avoid losing the line number info,
-            # or `inspect.stack()` will crash in the unit tests for `callsite_filename()`.
-            f.__code__ = f.__code__.replace(co_name=name)
-        else:
-            f.__code__ = CodeType(co.co_argcount, co.co_kwonlyargcount,
-                                  co.co_nlocals, co.co_stacksize, co.co_flags,
-                                  co.co_code, co.co_consts, co.co_names,
-                                  co.co_varnames, co.co_filename,
-                                  name,
-                                  co.co_firstlineno, co.co_lnotab, co.co_freevars,
-                                  co.co_cellvars)
+        f.__code__ = f.__code__.replace(co_name=name)
         return f
     return rename
 
diff --git a/unpythonic/syntax/__init__.py b/unpythonic/syntax/__init__.py
@@ -81,7 +81,8 @@
 
 # TODO: 0.16: AST pattern matching for `mcpyrate`? Would make destructuring easier. A writable representation (auto-viewify) is a pain to build, though...
 
-# TODO: Far future: Change decorator macro invocations to use [] instead of () to pass macro arguments. Requires Python 3.9, so the earliest time to do this is when 3.9 becomes the minimum Python version for `unpythonic`.
+# Parenthesis syntax for decorator macro arguments is deprecated; bracket syntax is preferred.
+# Parenthesis syntax is kept for backward compatibility.
 
 from .autocurry import *  # noqa: F401, F403
 from .autoref import *  # noqa: F401, F403
diff --git a/unpythonic/syntax/lambdatools.py b/unpythonic/syntax/lambdatools.py
@@ -451,10 +451,7 @@ def _envify(block_body):
     # second pass, inside-out
     def getargs(tree):  # tree: FunctionDef, AsyncFunctionDef, Lambda
         a = tree.args
-        if hasattr(a, "posonlyargs"):  # Python 3.8+: positional-only parameters
-            allargs = a.posonlyargs + a.args + a.kwonlyargs
-        else:
-            allargs = a.args + a.kwonlyargs
+        allargs = a.posonlyargs + a.args + a.kwonlyargs
         argnames = [x.arg for x in allargs]
         if a.vararg:
             argnames.append(a.vararg.arg)
diff --git a/unpythonic/syntax/letdo.py b/unpythonic/syntax/letdo.py
@@ -27,7 +27,6 @@
                  AsyncFunctionDef,
                  arguments, arg,
                  Load)
-import sys
 
 from mcpyrate.quotes import macros, q, u, n, a, t, h  # noqa: F401
 
@@ -590,10 +589,8 @@ def _dletseq_impl(bindings, body, kind):
 
     userargs = body.args  # original arguments to the def
     fname = body.name
-    noargs = arguments(args=[], kwonlyargs=[], vararg=None, kwarg=None,
+    noargs = arguments(args=[], posonlyargs=[], kwonlyargs=[], vararg=None, kwarg=None,
                        defaults=[], kw_defaults=[])
-    if sys.version_info >= (3, 8, 0):  # Python 3.8+: positional-only arguments
-        noargs.posonlyargs = []
     iname = gensym(f"{fname}_inner")
     body.args = noargs
     body.name = iname
@@ -927,11 +924,7 @@ def _do0(tree):
     elts = tree.elts
     # Use `local[]` and `do[]` as hygienically captured macros.
     #
-    # Python 3.8 and Python 3.9 require the parens around the walrus when used inside a subscript.
-    # TODO: Remove the parens when we bump minimum Python to 3.10.
-    # From https://docs.python.org/3/whatsnew/3.10.html:
-    #    Assignment expressions can now be used unparenthesized within set literals and set comprehensions, as well as in sequence indexes (but not slices).
-    newelts = [q[a[_our_local][(_do0_result := a[elts[0]])]],  # noqa: F821, local[] defines it inside the do[].
+    newelts = [q[a[_our_local][_do0_result := a[elts[0]]]],  # noqa: F821, local[] defines it inside the do[].
                *elts[1:],
                q[_do0_result]]  # noqa: F821
     return q[a[_our_do][t[newelts]]]  # do0[] is also just a do[]
diff --git a/unpythonic/syntax/letdoutil.py b/unpythonic/syntax/letdoutil.py
@@ -8,7 +8,6 @@
 
 from ast import (Call, Name, Subscript, Compare, In,
                  Tuple, List, Constant, BinOp, LShift, Lambda)
-import sys
 
 from mcpyrate import unparse
 from mcpyrate.astcompat import getconstant, Str, NamedExpr
@@ -22,14 +21,10 @@
 
 def _get_subscript_slice(tree):
     assert type(tree) is Subscript
-    if sys.version_info >= (3, 9, 0):  # Python 3.9+: the Index wrapper is gone.
-        return tree.slice
-    return tree.slice.value
+    return tree.slice
 def _set_subscript_slice(tree, newslice):  # newslice: AST
     assert type(tree) is Subscript
-    if sys.version_info >= (3, 9, 0):  # Python 3.9+: the Index wrapper is gone.
-        tree.slice = newslice
-    tree.slice.value = newslice
+    tree.slice = newslice
 def _canonize_macroargs_node(macroargs):
     # We do this like `mcpyrate.expander.destructure_candidate` does,
     # except that we also destructure a list.
@@ -197,7 +192,7 @@ def islet(tree, expanded=True):
         s = tree.value.id
         if any(s == x for x in deconames):
             return ("decorator", s)
-    if type(tree) is Call and type(tree.func) is Name:  # parenthesis syntax for macro arguments  TODO: Python 3.9+: remove once we bump minimum Python to 3.9
+    if type(tree) is Call and type(tree.func) is Name:  # Parenthesis syntax for macro arguments (deprecated; kept for backward compatibility)
         s = tree.func.id
         if any(s == x for x in deconames):
             return ("decorator", s)
@@ -214,7 +209,7 @@ def islet(tree, expanded=True):
         s = macro.value.id
         if any(s == x for x in exprnames):
             return ("lispy_expr", s)
-    elif type(macro) is Call and type(macro.func) is Name:  # parenthesis syntax for macro arguments  TODO: Python 3.9+: remove once we bump minimum Python to 3.9
+    elif type(macro) is Call and type(macro.func) is Name:  # Parenthesis syntax for macro arguments (deprecated; kept for backward compatibility)
         s = macro.func.id
         if any(s == x for x in exprnames):
             return ("lispy_expr", s)
@@ -497,7 +492,7 @@ def _getbindings(self):
                 # ^^^^^^^^^^
                 thetree = self._tree.value
 
-            if type(thetree) is Call:  # parenthesis syntax for macro arguments  TODO: Python 3.9+: remove once we bump minimum Python to 3.9
+            if type(thetree) is Call:  # Parenthesis syntax for macro arguments (deprecated; kept for backward compatibility)
                 return canonize_bindings(thetree.args)
             # Subscript
             theargs = _get_subscript_slice(thetree)
@@ -526,7 +521,7 @@ def _setbindings(self, newbindings):
                 # ^^^^^^^^^^
                 thetree = self._tree.value
 
-            if type(thetree) is Call:  # parenthesis syntax for macro arguments  TODO: Python 3.9+: remove once we bump minimum Python to 3.9
+            if type(thetree) is Call:  # Parenthesis syntax for macro arguments (deprecated; kept for backward compatibility)
                 thetree.args = newbindings
                 return
             _set_subscript_slice(thetree, Tuple(elts=newbindings))
diff --git a/unpythonic/syntax/letsyntax.py b/unpythonic/syntax/letsyntax.py
@@ -21,7 +21,6 @@
 from ast import Name, Call, Subscript, Tuple, Starred, Expr, With
 from copy import deepcopy
 from functools import partial
-import sys
 
 from mcpyrate import parametricmacro
 from mcpyrate.quotes import is_captured_value
@@ -328,7 +327,7 @@ def isbinding(tree):
             if type(ctxmanager) is Subscript and type(ctxmanager.value) is Name and ctxmanager.value.id == mode:
                 return mode, "template"
             # expr(...), block(...)
-            # parenthesis syntax for macro arguments  TODO: Python 3.9+: remove once we bump minimum Python to 3.9
+            # Parenthesis syntax for macro arguments (deprecated; kept for backward compatibility)
             if type(ctxmanager) is Call and type(ctxmanager.func) is Name and ctxmanager.func.id == mode:
                 return mode, "template"
         return False
@@ -369,10 +368,7 @@ def isbinding(tree):
 # -----------------------------------------------------------------------------
 
 def _get_subscript_args(tree):
-    if sys.version_info >= (3, 9, 0):  # Python 3.9+: the Index wrapper is gone.
-        theslice = tree.slice
-    else:
-        theslice = tree.slice.value
+    theslice = tree.slice
     if type(theslice) is Tuple:
         args = theslice.elts
     else:
@@ -389,7 +385,7 @@ def _analyze_lhs(tree):
     elif type(tree) is Subscript and type(tree.value) is Name:  # template f[x, ...]
         name = tree.value.id
         args = [a.id for a in _get_subscript_args(tree)]
-    # parenthesis syntax for macro arguments  TODO: Python 3.9+: remove once we bump minimum Python to 3.9
+    # Parenthesis syntax for macro arguments (deprecated; kept for backward compatibility)
     elif type(tree) is Call and type(tree.func) is Name:  # template f(x, ...)
         name = tree.func.id
         if any(type(a) is Starred for a in tree.args):  # *args (Python 3.5+)
@@ -445,7 +441,7 @@ def _substitute_templates(templates, tree):
         def isthisfunc(tree):
             if type(tree) is Subscript and type(tree.value) is Name and tree.value.id == name:
                 return True
-            # parenthesis syntax for macro arguments  TODO: Python 3.9+: remove once we bump minimum Python to 3.9
+            # Parenthesis syntax for macro arguments (deprecated; kept for backward compatibility)
             if type(tree) is Call and type(tree.func) is Name and tree.func.id == name:
                 return True
             return False
diff --git a/unpythonic/syntax/nameutil.py b/unpythonic/syntax/nameutil.py
@@ -9,7 +9,6 @@
            "is_unexpanded_expr_macro", "is_unexpanded_block_macro"]
 
 from ast import Name, Attribute, Subscript, Call, With
-import sys
 
 from mcpyrate.core import Done
 from mcpyrate.quotes import is_captured_macro, is_captured_value, lookup_macro
@@ -124,11 +123,7 @@ def is_unexpanded_expr_macro(macrofunction, expander, tree):
     # extract the expr
     macro = expander.isbound(name_node.id)
     if macro is macrofunction:
-        if sys.version_info >= (3, 9, 0):  # Python 3.9+: the Index wrapper is gone.
-            body = tree.slice
-        else:
-            body = tree.slice.value
-        return body
+        return tree.slice
     return False
 
 
@@ -154,7 +149,7 @@ def is_unexpanded_block_macro(macrofunction, expander, tree):
     # discard args if any
     if type(maybemacro) is Subscript:
         maybemacro = maybemacro.value
-    # parenthesis syntax for macro arguments  TODO: Python 3.9+: remove once we bump minimum Python to 3.9
+    # Parenthesis syntax for macro arguments (deprecated; kept for backward compatibility)
     elif type(maybemacro) is Call:
         maybemacro = maybemacro.func
 
diff --git a/unpythonic/syntax/prefix.py b/unpythonic/syntax/prefix.py
@@ -7,7 +7,6 @@
 __all__ = ["prefix", "q", "u", "kw"]
 
 from ast import Call, Starred, Tuple, Load, Subscript
-import sys
 
 from mcpyrate.quotes import macros, q, u, a, t  # noqa: F811, F401
 
@@ -194,11 +193,7 @@ def transform(self, tree):
             #       Expr
             #         Subscript
             if type(tree) is Subscript:
-                if sys.version_info >= (3, 9, 0):  # Python 3.9+: the Index wrapper is gone.
-                    body = tree.slice
-                else:
-                    body = tree.slice.value
-
+                body = tree.slice
                 if type(body) is Tuple:
                     # Skip the transformation of the expr tuple itself, but transform its elements.
                     # This skips the transformation of the macro argument tuple, too, because
diff --git a/unpythonic/syntax/scopeanalyzer.py b/unpythonic/syntax/scopeanalyzer.py
@@ -424,9 +424,7 @@ def extract_args(tree):
     if type(tree) not in (Lambda, FunctionDef, AsyncFunctionDef):
         raise ValueError(f"Expected a function definition AST node, got {tree}")
     a = tree.args
-    allargs = a.args + a.kwonlyargs
-    if hasattr(a, "posonlyargs"):  # Python 3.8+: positional-only arguments
-        allargs += a.posonlyargs
+    allargs = a.posonlyargs + a.args + a.kwonlyargs
     argnames = [x.arg for x in allargs]
     if a.vararg:
         argnames.append(a.vararg.arg)
diff --git a/unpythonic/syntax/tailtools.py b/unpythonic/syntax/tailtools.py
@@ -17,7 +17,6 @@
                  With, AsyncWith, If, IfExp, Try, Assign, Return, Expr,
                  Await,
                  copy_location)
-import sys
 
 from mcpyrate.quotes import macros, q, u, n, a, h  # noqa: F401
 
@@ -1110,13 +1109,12 @@ def prepare_call(tree):
                               body=q[n["cc"]],
                               orelse=non)
         contarguments = arguments(args=[arg(arg=x) for x in targets],
+                                  posonlyargs=[],
                                   kwonlyargs=[arg(arg="cc"), arg(arg="_pcc")],
                                   vararg=(arg(arg=starget) if starget else None),
                                   kwarg=None,
                                   defaults=posargdefaults,
                                   kw_defaults=[q[h[identity]], maybe_capture])
-        if sys.version_info >= (3, 8, 0):  # Python 3.8+: positional-only arguments
-            contarguments.posonlyargs = []
         funcdef = FDef(name=contname,
                        args=contarguments,
                        body=contbody,
diff --git a/unpythonic/syntax/testingtools.py b/unpythonic/syntax/testingtools.py
diff --git a/unpythonic/syntax/tests/test_conts_multishot.py b/unpythonic/syntax/tests/test_conts_multishot.py
diff --git a/unpythonic/syntax/tests/test_letdo.py b/unpythonic/syntax/tests/test_letdo.py
diff --git a/unpythonic/syntax/tests/test_letdoutil.py b/unpythonic/syntax/tests/test_letdoutil.py
diff --git a/unpythonic/typecheck.py b/unpythonic/typecheck.py
