add ruff linter alongside flake8, migrate CI

Add ruff with E/W/F/SIM rules to pyproject.toml, replace flake8 in CI
workflow. Keep flake8 + flake8rc for Emacs. Per-site noqas for macro-injected
names and continuation short-circuit tests.

Fix: E714 not-is-test, E721 type comparisons, SIM201 negated equality,
SIM110 loop-to-all/any, unused sys import. Noqa SIM401 on custom .get()
implementations, E741 on Lisp-conventional `l` parameter.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: Technologicat

.github/workflows/ci.yml

@@ -21,18 +21,14 @@ jobs:
     - name: Set up Python
       uses: actions/setup-python@v6
       with:
-        # Use latest Python so flake8 can parse all syntax (e.g. except* requires 3.11+)
         python-version: "3.14"
-    - name: Install flake8
+    - name: Install ruff
       run: |
         python -m pip install --upgrade pip
-        pip install flake8
-    - name: Lint with flake8
+        pip install ruff
+    - name: Lint with ruff
       run: |
-        # stop the build if there are Python syntax errors or undefined names
-        flake8 . --config=flake8rc --count --select=E9,F63,F7,F82 --show-source --statistics
-        # exit-zero treats all errors as warnings. The GitHub editor is 127 chars wide
-        flake8 . --config=flake8rc --count --exit-zero --max-complexity=100 --max-line-length=127 --statistics
+        ruff check .
 
   test:
     needs: lint

CLAUDE.md

@@ -66,13 +66,11 @@ Each test module exports a `runtests()` function. Tests are grouped with `testse
 ## Linting
 
 ```bash
-# As in CI — hard errors (syntax errors, undefined names)
-flake8 . --config=flake8rc --select=E9,F63,F7,F82 --show-source
-
-# Soft warnings
-flake8 . --config=flake8rc --exit-zero --max-line-length=127
+ruff check <changed .py files>   # primary linter (config in pyproject.toml)
 ```
 
+Legacy `flake8rc` also present (used by Emacs flycheck, not by CI or CC).
+
 ## Code structure and conventions
 
 - **Regular code** in `unpythonic/`, **macros** in `unpythonic/syntax/`, **REPL networking** in `unpythonic/net/`, **dialects** in `unpythonic/dialects/`.

pyproject.toml

@@ -49,6 +49,7 @@ Repository = "https://github.com/Technologicat/unpythonic"
 
 [dependency-groups]
 dev = [
+    "ruff>=0.14.0",
     "flake8",
     "autopep8",
     "importmagic",
@@ -81,5 +82,45 @@ excludes = ["**/tests", "**/__pycache__"]
 
 # most python tools at this point, including mypy, have support for sourcing configuration from pyproject.toml
 # making the setup.cfg file unnecessary
+[tool.ruff]
+line-length = 130
+target-version = "py310"
+exclude = [
+    ".git",
+    "__pycache__",
+    "build",
+    "dist",
+    ".venv",
+    "unpythonic/syntax/tests/test_scopeanalyzer_3_11.py",  # except* syntax requires 3.11+
+]
+
+[tool.ruff.lint]
+select = ["E", "W", "F", "SIM"]
+ignore = [
+    # pycodestyle
+    "E203",   # whitespace before ':' — needed for slice alignment
+    "E265",   # block comment should start with '# ' — commented-out code, markers
+    "E301",   # expected 1 blank line — blank lines are semantic paragraph breaks
+    "E302",   # expected 2 blank lines before def — same
+    "E305",   # expected 2 blank lines after end — same
+    "E306",   # expected blank line before nested def — same
+    "E402",   # module level import not at top — conditional/deferred imports
+    "E501",   # line too long — advisory, not enforced
+    "E731",   # lambda assignment — closures are idiomatic in this codebase
+    # flake8-simplify
+    "SIM102",  # collapsible if — nested ifs often represent distinct semantic guards
+    "SIM105",  # contextlib.suppress — try/except/pass is more flexible and explicit
+    "SIM108",  # ternary instead of if/else — often less readable, no real gain
+    "SIM114",  # combine if branches — match-casing style; autofix would damage semantics
+    "SIM117",  # combine with statements — nesting shows parent/child; also mcpyrate AST differences
+    "SIM118",  # in-dict-keys — explicit .keys() marks the variable as a dictlike
+    "SIM300",  # yoda conditions — natural reading order preferred
+    "SIM910",  # dict.get with None default — explicit None documents programmer intent
+    "SIM103",  # return condition directly — multi-guard patterns; autofix breaks visual consistency
+]
+
+[tool.ruff.lint.per-file-ignores]
+"__init__.py" = ["F401", "F403"]  # re-exports via star-import
+
 [tool.mypy]
 show_error_codes = true

unpythonic/collections.py

@@ -571,10 +571,7 @@ def __eq__(self, other):
             return True
         if len(self) != len(other):
             return False
-        for v1, v2 in zip(self, other):
-            if v1 != v2:
-                return False
-        return True
+        return all(v1 == v2 for v1, v2 in zip(self, other))
 
 class roview(SequenceView, _StrReprEqMixin):
     """Read-only live view into a sequence.

unpythonic/dialects/listhell.py

@@ -15,7 +15,7 @@
 
 class Listhell(Dialect):
     def transform_ast(self, tree):  # tree is an ast.Module
-        with q as template:
+        with q as template:  # noqa: F823 -- `q` is a macro-injected name
             __lang__ = "Listhell"  # noqa: F841, just provide it to user code.
             from unpythonic.syntax import macros, prefix, q, u, kw, autocurry  # noqa: F401, F811
             # Auxiliary syntax elements for the macros

unpythonic/dynassign.py

@@ -245,7 +245,7 @@ def keys(self):
     def values(self):
         return self.asdict().values()
     def get(self, k, default=None):
-        return self[k] if k in self else default
+        return self[k] if k in self else default  # noqa: SIM401 -- this IS the .get() implementation
     def __eq__(self, other):  # dyn is a singleton, but its contents can be compared to another mapping.
         return other == self.asdict()
 

unpythonic/env.py

@@ -122,7 +122,7 @@ def keys(self):
     def values(self):
         return self._env.values()
     def get(self, k, default=None):
-        return self[k] if k in self else default
+        return self[k] if k in self else default  # noqa: SIM401 -- this IS the .get() implementation
     def __eq__(self, other):
         return other == self._env
 

unpythonic/funutil.py

@@ -360,7 +360,7 @@ def values(self):
         return self.kwrets.values()
     def get(self, k, default=None):
         """Dict-like `get` for the named part."""
-        return self[k] if k in self else default
+        return self[k] if k in self else default  # noqa: SIM401 -- this IS the .get() implementation
 
     # comparison
     def __eq__(self, other):

unpythonic/it.py

@@ -933,7 +933,4 @@ def allsame(iterable):
         x0 = next(it)
     except StopIteration:
         return True  # like all(()) is True
-    for x in it:
-        if x != x0:
-            return False
-    return True
+    return all(x == x0 for x in it)

unpythonic/llist.py

@@ -255,10 +255,7 @@ def __eq__(self, other):
             try:  # duck test linked lists
                 ia, ib = (LinkedListIterator(x) for x in (self, other))
                 fill = object()  # gensym("fill"), but object() is much faster, and we don't need a label, or pickle support.
-                for a, b in zip_longest(ia, ib, fillvalue=fill):
-                    if a != b:
-                        return False
-                return True
+                return all(a == b for a, b in zip_longest(ia, ib, fillvalue=fill))
             except TypeError:
                 return self.car == other.car and self.cdr == other.cdr
         return False
@@ -374,7 +371,7 @@ def lappend_two(l1, l2):
         return foldr(cons, l2, l1)
     return foldr(lappend_two, nil, ls)
 
-def member(x, l):
+def member(x, l):  # noqa: E741 -- standard Lisp name for a linked list
     """Walk linked list l and check if item x is in it.
 
     Returns: