diff --git a/.github/CODEOWNERS b/.github/CODEOWNERS index 4bea55a495f776..45d06317c265be 100644 --- a/.github/CODEOWNERS +++ b/.github/CODEOWNERS @@ -188,6 +188,7 @@ Python/ast_opt.c @isidentical @eclips4 Parser/asdl.py @isidentical @JelleZijlstra @eclips4 Parser/asdl_c.py @isidentical @JelleZijlstra @eclips4 Lib/ast.py @isidentical @JelleZijlstra @eclips4 +Lib/_ast_unparse.py @isidentical @JelleZijlstra @eclips4 Lib/test/test_ast/ @eclips4 # Mock diff --git a/Lib/_ast_unparse.py b/Lib/_ast_unparse.py new file mode 100644 index 00000000000000..c03f9bd4c1d40b --- /dev/null +++ b/Lib/_ast_unparse.py @@ -0,0 +1,1150 @@ +# This module contains ``ast.unparse()``, defined here +# to improve the import time for the ``ast`` module. +import sys +from _ast import * +from ast import NodeVisitor +from contextlib import contextmanager, nullcontext +from enum import IntEnum, auto, _simple_enum + +__all__ = ('unparse',) + +# Large float and imaginary literals get turned into infinities in the AST. +# We unparse those infinities to INFSTR. +_INFSTR = "1e" + repr(sys.float_info.max_10_exp + 1) + +@_simple_enum(IntEnum) +class _Precedence: + """Precedence table that originated from python grammar.""" + + NAMED_EXPR = auto() # := + TUPLE = auto() # , + YIELD = auto() # 'yield', 'yield from' + TEST = auto() # 'if'-'else', 'lambda' + OR = auto() # 'or' + AND = auto() # 'and' + NOT = auto() # 'not' + CMP = auto() # '<', '>', '==', '>=', '<=', '!=', + # 'in', 'not in', 'is', 'is not' + EXPR = auto() + BOR = EXPR # '|' + BXOR = auto() # '^' + BAND = auto() # '&' + SHIFT = auto() # '<<', '>>' + ARITH = auto() # '+', '-' + TERM = auto() # '*', '@', '/', '%', '//' + FACTOR = auto() # unary '+', '-', '~' + POWER = auto() # '**' + AWAIT = auto() # 'await' + ATOM = auto() + + def next(self): + try: + return self.__class__(self + 1) + except ValueError: + return self + + +_SINGLE_QUOTES = ("'", '"') +_MULTI_QUOTES = ('"""', "'''") +_ALL_QUOTES = (*_SINGLE_QUOTES, *_MULTI_QUOTES) + +class _Unparser(NodeVisitor): + """Methods in this class recursively traverse an AST and + output source code for the abstract syntax; original formatting + is disregarded.""" + + def __init__(self): + self._source = [] + self._precedences = {} + self._type_ignores = {} + self._indent = 0 + self._in_try_star = False + self._in_interactive = False + + def interleave(self, inter, f, seq): + """Call f on each item in seq, calling inter() in between.""" + seq = iter(seq) + try: + f(next(seq)) + except StopIteration: + pass + else: + for x in seq: + inter() + f(x) + + def items_view(self, traverser, items): + """Traverse and separate the given *items* with a comma and append it to + the buffer. If *items* is a single item sequence, a trailing comma + will be added.""" + if len(items) == 1: + traverser(items[0]) + self.write(",") + else: + self.interleave(lambda: self.write(", "), traverser, items) + + def maybe_newline(self): + """Adds a newline if it isn't the start of generated source""" + if self._source: + self.write("\n") + + def maybe_semicolon(self): + """Adds a "; " delimiter if it isn't the start of generated source""" + if self._source: + self.write("; ") + + def fill(self, text="", *, allow_semicolon=True): + """Indent a piece of text and append it, according to the current + indentation level, or only delineate with semicolon if applicable""" + if self._in_interactive and not self._indent and allow_semicolon: + self.maybe_semicolon() + self.write(text) + else: + self.maybe_newline() + self.write(" " * self._indent + text) + + def write(self, *text): + """Add new source parts""" + self._source.extend(text) + + @contextmanager + def buffered(self, buffer = None): + if buffer is None: + buffer = [] + + original_source = self._source + self._source = buffer + yield buffer + self._source = original_source + + @contextmanager + def block(self, *, extra = None): + """A context manager for preparing the source for blocks. It adds + the character':', increases the indentation on enter and decreases + the indentation on exit. If *extra* is given, it will be directly + appended after the colon character. + """ + self.write(":") + if extra: + self.write(extra) + self._indent += 1 + yield + self._indent -= 1 + + @contextmanager + def delimit(self, start, end): + """A context manager for preparing the source for expressions. It adds + *start* to the buffer and enters, after exit it adds *end*.""" + + self.write(start) + yield + self.write(end) + + def delimit_if(self, start, end, condition): + if condition: + return self.delimit(start, end) + else: + return nullcontext() + + def require_parens(self, precedence, node): + """Shortcut to adding precedence related parens""" + return self.delimit_if("(", ")", self.get_precedence(node) > precedence) + + def get_precedence(self, node): + return self._precedences.get(node, _Precedence.TEST) + + def set_precedence(self, precedence, *nodes): + for node in nodes: + self._precedences[node] = precedence + + def get_raw_docstring(self, node): + """If a docstring node is found in the body of the *node* parameter, + return that docstring node, None otherwise. + + Logic mirrored from ``_PyAST_GetDocString``.""" + if not isinstance( + node, (AsyncFunctionDef, FunctionDef, ClassDef, Module) + ) or len(node.body) < 1: + return None + node = node.body[0] + if not isinstance(node, Expr): + return None + node = node.value + if isinstance(node, Constant) and isinstance(node.value, str): + return node + + def get_type_comment(self, node): + comment = self._type_ignores.get(node.lineno) or node.type_comment + if comment is not None: + return f" # type: {comment}" + + def traverse(self, node): + if isinstance(node, list): + for item in node: + self.traverse(item) + else: + super().visit(node) + + # Note: as visit() resets the output text, do NOT rely on + # NodeVisitor.generic_visit to handle any nodes (as it calls back in to + # the subclass visit() method, which resets self._source to an empty list) + def visit(self, node): + """Outputs a source code string that, if converted back to an ast + (using ast.parse) will generate an AST equivalent to *node*""" + self._source = [] + self.traverse(node) + return "".join(self._source) + + def _write_docstring_and_traverse_body(self, node): + if (docstring := self.get_raw_docstring(node)): + self._write_docstring(docstring) + self.traverse(node.body[1:]) + else: + self.traverse(node.body) + + def visit_Module(self, node): + self._type_ignores = { + ignore.lineno: f"ignore{ignore.tag}" + for ignore in node.type_ignores + } + try: + self._write_docstring_and_traverse_body(node) + finally: + self._type_ignores.clear() + + def visit_Interactive(self, node): + self._in_interactive = True + try: + self._write_docstring_and_traverse_body(node) + finally: + self._in_interactive = False + + def visit_FunctionType(self, node): + with self.delimit("(", ")"): + self.interleave( + lambda: self.write(", "), self.traverse, node.argtypes + ) + + self.write(" -> ") + self.traverse(node.returns) + + def visit_Expr(self, node): + self.fill() + self.set_precedence(_Precedence.YIELD, node.value) + self.traverse(node.value) + + def visit_NamedExpr(self, node): + with self.require_parens(_Precedence.NAMED_EXPR, node): + self.set_precedence(_Precedence.ATOM, node.target, node.value) + self.traverse(node.target) + self.write(" := ") + self.traverse(node.value) + + def visit_Import(self, node): + self.fill("import ") + self.interleave(lambda: self.write(", "), self.traverse, node.names) + + def visit_ImportFrom(self, node): + self.fill("from ") + self.write("." * (node.level or 0)) + if node.module: + self.write(node.module) + self.write(" import ") + self.interleave(lambda: self.write(", "), self.traverse, node.names) + + def visit_Assign(self, node): + self.fill() + for target in node.targets: + self.set_precedence(_Precedence.TUPLE, target) + self.traverse(target) + self.write(" = ") + self.traverse(node.value) + if type_comment := self.get_type_comment(node): + self.write(type_comment) + + def visit_AugAssign(self, node): + self.fill() + self.traverse(node.target) + self.write(" " + self.binop[node.op.__class__.__name__] + "= ") + self.traverse(node.value) + + def visit_AnnAssign(self, node): + self.fill() + with self.delimit_if("(", ")", not node.simple and isinstance(node.target, Name)): + self.traverse(node.target) + self.write(": ") + self.traverse(node.annotation) + if node.value: + self.write(" = ") + self.traverse(node.value) + + def visit_Return(self, node): + self.fill("return") + if node.value: + self.write(" ") + self.traverse(node.value) + + def visit_Pass(self, node): + self.fill("pass") + + def visit_Break(self, node): + self.fill("break") + + def visit_Continue(self, node): + self.fill("continue") + + def visit_Delete(self, node): + self.fill("del ") + self.interleave(lambda: self.write(", "), self.traverse, node.targets) + + def visit_Assert(self, node): + self.fill("assert ") + self.traverse(node.test) + if node.msg: + self.write(", ") + self.traverse(node.msg) + + def visit_Global(self, node): + self.fill("global ") + self.interleave(lambda: self.write(", "), self.write, node.names) + + def visit_Nonlocal(self, node): + self.fill("nonlocal ") + self.interleave(lambda: self.write(", "), self.write, node.names) + + def visit_Await(self, node): + with self.require_parens(_Precedence.AWAIT, node): + self.write("await") + if node.value: + self.write(" ") + self.set_precedence(_Precedence.ATOM, node.value) + self.traverse(node.value) + + def visit_Yield(self, node): + with self.require_parens(_Precedence.YIELD, node): + self.write("yield") + if node.value: + self.write(" ") + self.set_precedence(_Precedence.ATOM, node.value) + self.traverse(node.value) + + def visit_YieldFrom(self, node): + with self.require_parens(_Precedence.YIELD, node): + self.write("yield from ") + if not node.value: + raise ValueError("Node can't be used without a value attribute.") + self.set_precedence(_Precedence.ATOM, node.value) + self.traverse(node.value) + + def visit_Raise(self, node): + self.fill("raise") + if not node.exc: + if node.cause: + raise ValueError(f"Node can't use cause without an exception.") + return + self.write(" ") + self.traverse(node.exc) + if node.cause: + self.write(" from ") + self.traverse(node.cause) + + def do_visit_try(self, node): + self.fill("try", allow_semicolon=False) + with self.block(): + self.traverse(node.body) + for ex in node.handlers: + self.traverse(ex) + if node.orelse: + self.fill("else", allow_semicolon=False) + with self.block(): + self.traverse(node.orelse) + if node.finalbody: + self.fill("finally", allow_semicolon=False) + with self.block(): + self.traverse(node.finalbody) + + def visit_Try(self, node): + prev_in_try_star = self._in_try_star + try: + self._in_try_star = False + self.do_visit_try(node) + finally: + self._in_try_star = prev_in_try_star + + def visit_TryStar(self, node): + prev_in_try_star = self._in_try_star + try: + self._in_try_star = True + self.do_visit_try(node) + finally: + self._in_try_star = prev_in_try_star + + def visit_ExceptHandler(self, node): + self.fill("except*" if self._in_try_star else "except", allow_semicolon=False) + if node.type: + self.write(" ") + self.traverse(node.type) + if node.name: + self.write(" as ") + self.write(node.name) + with self.block(): + self.traverse(node.body) + + def visit_ClassDef(self, node): + self.maybe_newline() + for deco in node.decorator_list: + self.fill("@", allow_semicolon=False) + self.traverse(deco) + self.fill("class " + node.name, allow_semicolon=False) + if hasattr(node, "type_params"): + self._type_params_helper(node.type_params) + with self.delimit_if("(", ")", condition = node.bases or node.keywords): + comma = False + for e in node.bases: + if comma: + self.write(", ") + else: + comma = True + self.traverse(e) + for e in node.keywords: + if comma: + self.write(", ") + else: + comma = True + self.traverse(e) + + with self.block(): + self._write_docstring_and_traverse_body(node) + + def visit_FunctionDef(self, node): + self._function_helper(node, "def") + + def visit_AsyncFunctionDef(self, node): + self._function_helper(node, "async def") + + def _function_helper(self, node, fill_suffix): + self.maybe_newline() + for deco in node.decorator_list: + self.fill("@", allow_semicolon=False) + self.traverse(deco) + def_str = fill_suffix + " " + node.name + self.fill(def_str, allow_semicolon=False) + if hasattr(node, "type_params"): + self._type_params_helper(node.type_params) + with self.delimit("(", ")"): + self.traverse(node.args) + if node.returns: + self.write(" -> ") + self.traverse(node.returns) + with self.block(extra=self.get_type_comment(node)): + self._write_docstring_and_traverse_body(node) + + def _type_params_helper(self, type_params): + if type_params is not None and len(type_params) > 0: + with self.delimit("[", "]"): + self.interleave(lambda: self.write(", "), self.traverse, type_params) + + def visit_TypeVar(self, node): + self.write(node.name) + if node.bound: + self.write(": ") + self.traverse(node.bound) + if node.default_value: + self.write(" = ") + self.traverse(node.default_value) + + def visit_TypeVarTuple(self, node): + self.write("*" + node.name) + if node.default_value: + self.write(" = ") + self.traverse(node.default_value) + + def visit_ParamSpec(self, node): + self.write("**" + node.name) + if node.default_value: + self.write(" = ") + self.traverse(node.default_value) + + def visit_TypeAlias(self, node): + self.fill("type ") + self.traverse(node.name) + self._type_params_helper(node.type_params) + self.write(" = ") + self.traverse(node.value) + + def visit_For(self, node): + self._for_helper("for ", node) + + def visit_AsyncFor(self, node): + self._for_helper("async for ", node) + + def _for_helper(self, fill, node): + self.fill(fill, allow_semicolon=False) + self.set_precedence(_Precedence.TUPLE, node.target) + self.traverse(node.target) + self.write(" in ") + self.traverse(node.iter) + with self.block(extra=self.get_type_comment(node)): + self.traverse(node.body) + if node.orelse: + self.fill("else", allow_semicolon=False) + with self.block(): + self.traverse(node.orelse) + + def visit_If(self, node): + self.fill("if ", allow_semicolon=False) + self.traverse(node.test) + with self.block(): + self.traverse(node.body) + # collapse nested ifs into equivalent elifs. + while node.orelse and len(node.orelse) == 1 and isinstance(node.orelse[0], If): + node = node.orelse[0] + self.fill("elif ", allow_semicolon=False) + self.traverse(node.test) + with self.block(): + self.traverse(node.body) + # final else + if node.orelse: + self.fill("else", allow_semicolon=False) + with self.block(): + self.traverse(node.orelse) + + def visit_While(self, node): + self.fill("while ", allow_semicolon=False) + self.traverse(node.test) + with self.block(): + self.traverse(node.body) + if node.orelse: + self.fill("else", allow_semicolon=False) + with self.block(): + self.traverse(node.orelse) + + def visit_With(self, node): + self.fill("with ", allow_semicolon=False) + self.interleave(lambda: self.write(", "), self.traverse, node.items) + with self.block(extra=self.get_type_comment(node)): + self.traverse(node.body) + + def visit_AsyncWith(self, node): + self.fill("async with ", allow_semicolon=False) + self.interleave(lambda: self.write(", "), self.traverse, node.items) + with self.block(extra=self.get_type_comment(node)): + self.traverse(node.body) + + def _str_literal_helper( + self, string, *, quote_types=_ALL_QUOTES, escape_special_whitespace=False + ): + """Helper for writing string literals, minimizing escapes. + Returns the tuple (string literal to write, possible quote types). + """ + def escape_char(c): + # \n and \t are non-printable, but we only escape them if + # escape_special_whitespace is True + if not escape_special_whitespace and c in "\n\t": + return c + # Always escape backslashes and other non-printable characters + if c == "\\" or not c.isprintable(): + return c.encode("unicode_escape").decode("ascii") + return c + + escaped_string = "".join(map(escape_char, string)) + possible_quotes = quote_types + if "\n" in escaped_string: + possible_quotes = [q for q in possible_quotes if q in _MULTI_QUOTES] + possible_quotes = [q for q in possible_quotes if q not in escaped_string] + if not possible_quotes: + # If there aren't any possible_quotes, fallback to using repr + # on the original string. Try to use a quote from quote_types, + # e.g., so that we use triple quotes for docstrings. + string = repr(string) + quote = next((q for q in quote_types if string[0] in q), string[0]) + return string[1:-1], [quote] + if escaped_string: + # Sort so that we prefer '''"''' over """\"""" + possible_quotes.sort(key=lambda q: q[0] == escaped_string[-1]) + # If we're using triple quotes and we'd need to escape a final + # quote, escape it + if possible_quotes[0][0] == escaped_string[-1]: + assert len(possible_quotes[0]) == 3 + escaped_string = escaped_string[:-1] + "\\" + escaped_string[-1] + return escaped_string, possible_quotes + + def _write_str_avoiding_backslashes(self, string, *, quote_types=_ALL_QUOTES): + """Write string literal value with a best effort attempt to avoid backslashes.""" + string, quote_types = self._str_literal_helper(string, quote_types=quote_types) + quote_type = quote_types[0] + self.write(f"{quote_type}{string}{quote_type}") + + def visit_JoinedStr(self, node): + self.write("f") + + fstring_parts = [] + for value in node.values: + with self.buffered() as buffer: + self._write_fstring_inner(value) + fstring_parts.append( + ("".join(buffer), isinstance(value, Constant)) + ) + + new_fstring_parts = [] + quote_types = list(_ALL_QUOTES) + fallback_to_repr = False + for value, is_constant in fstring_parts: + if is_constant: + value, new_quote_types = self._str_literal_helper( + value, + quote_types=quote_types, + escape_special_whitespace=True, + ) + if set(new_quote_types).isdisjoint(quote_types): + fallback_to_repr = True + break + quote_types = new_quote_types + else: + if "\n" in value: + quote_types = [q for q in quote_types if q in _MULTI_QUOTES] + assert quote_types + + new_quote_types = [q for q in quote_types if q not in value] + if new_quote_types: + quote_types = new_quote_types + new_fstring_parts.append(value) + + if fallback_to_repr: + # If we weren't able to find a quote type that works for all parts + # of the JoinedStr, fallback to using repr and triple single quotes. + quote_types = ["'''"] + new_fstring_parts.clear() + for value, is_constant in fstring_parts: + if is_constant: + value = repr('"' + value) # force repr to use single quotes + expected_prefix = "'\"" + assert value.startswith(expected_prefix), repr(value) + value = value[len(expected_prefix):-1] + new_fstring_parts.append(value) + + value = "".join(new_fstring_parts) + quote_type = quote_types[0] + self.write(f"{quote_type}{value}{quote_type}") + + def _write_fstring_inner(self, node, is_format_spec=False): + if isinstance(node, JoinedStr): + # for both the f-string itself, and format_spec + for value in node.values: + self._write_fstring_inner(value, is_format_spec=is_format_spec) + elif isinstance(node, Constant) and isinstance(node.value, str): + value = node.value.replace("{", "{{").replace("}", "}}") + + if is_format_spec: + value = value.replace("\\", "\\\\") + value = value.replace("'", "\\'") + value = value.replace('"', '\\"') + value = value.replace("\n", "\\n") + self.write(value) + elif isinstance(node, FormattedValue): + self.visit_FormattedValue(node) + else: + raise ValueError(f"Unexpected node inside JoinedStr, {node!r}") + + def visit_FormattedValue(self, node): + def unparse_inner(inner): + unparser = type(self)() + unparser.set_precedence(_Precedence.TEST.next(), inner) + return unparser.visit(inner) + + with self.delimit("{", "}"): + expr = unparse_inner(node.value) + if expr.startswith("{"): + # Separate pair of opening brackets as "{ {" + self.write(" ") + self.write(expr) + if node.conversion != -1: + self.write(f"!{chr(node.conversion)}") + if node.format_spec: + self.write(":") + self._write_fstring_inner(node.format_spec, is_format_spec=True) + + def visit_Name(self, node): + self.write(node.id) + + def _write_docstring(self, node): + self.fill(allow_semicolon=False) + if node.kind == "u": + self.write("u") + self._write_str_avoiding_backslashes(node.value, quote_types=_MULTI_QUOTES) + + def _write_constant(self, value): + if isinstance(value, (float, complex)): + # Substitute overflowing decimal literal for AST infinities, + # and inf - inf for NaNs. + self.write( + repr(value) + .replace("inf", _INFSTR) + .replace("nan", f"({_INFSTR}-{_INFSTR})") + ) + else: + self.write(repr(value)) + + def visit_Constant(self, node): + value = node.value + if isinstance(value, tuple): + with self.delimit("(", ")"): + self.items_view(self._write_constant, value) + elif value is ...: + self.write("...") + else: + if node.kind == "u": + self.write("u") + self._write_constant(node.value) + + def visit_List(self, node): + with self.delimit("[", "]"): + self.interleave(lambda: self.write(", "), self.traverse, node.elts) + + def visit_ListComp(self, node): + with self.delimit("[", "]"): + self.traverse(node.elt) + for gen in node.generators: + self.traverse(gen) + + def visit_GeneratorExp(self, node): + with self.delimit("(", ")"): + self.traverse(node.elt) + for gen in node.generators: + self.traverse(gen) + + def visit_SetComp(self, node): + with self.delimit("{", "}"): + self.traverse(node.elt) + for gen in node.generators: + self.traverse(gen) + + def visit_DictComp(self, node): + with self.delimit("{", "}"): + self.traverse(node.key) + self.write(": ") + self.traverse(node.value) + for gen in node.generators: + self.traverse(gen) + + def visit_comprehension(self, node): + if node.is_async: + self.write(" async for ") + else: + self.write(" for ") + self.set_precedence(_Precedence.TUPLE, node.target) + self.traverse(node.target) + self.write(" in ") + self.set_precedence(_Precedence.TEST.next(), node.iter, *node.ifs) + self.traverse(node.iter) + for if_clause in node.ifs: + self.write(" if ") + self.traverse(if_clause) + + def visit_IfExp(self, node): + with self.require_parens(_Precedence.TEST, node): + self.set_precedence(_Precedence.TEST.next(), node.body, node.test) + self.traverse(node.body) + self.write(" if ") + self.traverse(node.test) + self.write(" else ") + self.set_precedence(_Precedence.TEST, node.orelse) + self.traverse(node.orelse) + + def visit_Set(self, node): + if node.elts: + with self.delimit("{", "}"): + self.interleave(lambda: self.write(", "), self.traverse, node.elts) + else: + # `{}` would be interpreted as a dictionary literal, and + # `set` might be shadowed. Thus: + self.write('{*()}') + + def visit_Dict(self, node): + def write_key_value_pair(k, v): + self.traverse(k) + self.write(": ") + self.traverse(v) + + def write_item(item): + k, v = item + if k is None: + # for dictionary unpacking operator in dicts {**{'y': 2}} + # see PEP 448 for details + self.write("**") + self.set_precedence(_Precedence.EXPR, v) + self.traverse(v) + else: + write_key_value_pair(k, v) + + with self.delimit("{", "}"): + self.interleave( + lambda: self.write(", "), write_item, zip(node.keys, node.values) + ) + + def visit_Tuple(self, node): + with self.delimit_if( + "(", + ")", + len(node.elts) == 0 or self.get_precedence(node) > _Precedence.TUPLE + ): + self.items_view(self.traverse, node.elts) + + unop = {"Invert": "~", "Not": "not", "UAdd": "+", "USub": "-"} + unop_precedence = { + "not": _Precedence.NOT, + "~": _Precedence.FACTOR, + "+": _Precedence.FACTOR, + "-": _Precedence.FACTOR, + } + + def visit_UnaryOp(self, node): + operator = self.unop[node.op.__class__.__name__] + operator_precedence = self.unop_precedence[operator] + with self.require_parens(operator_precedence, node): + self.write(operator) + # factor prefixes (+, -, ~) shouldn't be separated + # from the value they belong, (e.g: +1 instead of + 1) + if operator_precedence is not _Precedence.FACTOR: + self.write(" ") + self.set_precedence(operator_precedence, node.operand) + self.traverse(node.operand) + + binop = { + "Add": "+", + "Sub": "-", + "Mult": "*", + "MatMult": "@", + "Div": "/", + "Mod": "%", + "LShift": "<<", + "RShift": ">>", + "BitOr": "|", + "BitXor": "^", + "BitAnd": "&", + "FloorDiv": "//", + "Pow": "**", + } + + binop_precedence = { + "+": _Precedence.ARITH, + "-": _Precedence.ARITH, + "*": _Precedence.TERM, + "@": _Precedence.TERM, + "/": _Precedence.TERM, + "%": _Precedence.TERM, + "<<": _Precedence.SHIFT, + ">>": _Precedence.SHIFT, + "|": _Precedence.BOR, + "^": _Precedence.BXOR, + "&": _Precedence.BAND, + "//": _Precedence.TERM, + "**": _Precedence.POWER, + } + + binop_rassoc = frozenset(("**",)) + def visit_BinOp(self, node): + operator = self.binop[node.op.__class__.__name__] + operator_precedence = self.binop_precedence[operator] + with self.require_parens(operator_precedence, node): + if operator in self.binop_rassoc: + left_precedence = operator_precedence.next() + right_precedence = operator_precedence + else: + left_precedence = operator_precedence + right_precedence = operator_precedence.next() + + self.set_precedence(left_precedence, node.left) + self.traverse(node.left) + self.write(f" {operator} ") + self.set_precedence(right_precedence, node.right) + self.traverse(node.right) + + cmpops = { + "Eq": "==", + "NotEq": "!=", + "Lt": "<", + "LtE": "<=", + "Gt": ">", + "GtE": ">=", + "Is": "is", + "IsNot": "is not", + "In": "in", + "NotIn": "not in", + } + + def visit_Compare(self, node): + with self.require_parens(_Precedence.CMP, node): + self.set_precedence(_Precedence.CMP.next(), node.left, *node.comparators) + self.traverse(node.left) + for o, e in zip(node.ops, node.comparators): + self.write(" " + self.cmpops[o.__class__.__name__] + " ") + self.traverse(e) + + boolops = {"And": "and", "Or": "or"} + boolop_precedence = {"and": _Precedence.AND, "or": _Precedence.OR} + + def visit_BoolOp(self, node): + operator = self.boolops[node.op.__class__.__name__] + operator_precedence = self.boolop_precedence[operator] + + def increasing_level_traverse(node): + nonlocal operator_precedence + operator_precedence = operator_precedence.next() + self.set_precedence(operator_precedence, node) + self.traverse(node) + + with self.require_parens(operator_precedence, node): + s = f" {operator} " + self.interleave(lambda: self.write(s), increasing_level_traverse, node.values) + + def visit_Attribute(self, node): + self.set_precedence(_Precedence.ATOM, node.value) + self.traverse(node.value) + # Special case: 3.__abs__() is a syntax error, so if node.value + # is an integer literal then we need to either parenthesize + # it or add an extra space to get 3 .__abs__(). + if isinstance(node.value, Constant) and isinstance(node.value.value, int): + self.write(" ") + self.write(".") + self.write(node.attr) + + def visit_Call(self, node): + self.set_precedence(_Precedence.ATOM, node.func) + self.traverse(node.func) + with self.delimit("(", ")"): + comma = False + for e in node.args: + if comma: + self.write(", ") + else: + comma = True + self.traverse(e) + for e in node.keywords: + if comma: + self.write(", ") + else: + comma = True + self.traverse(e) + + def visit_Subscript(self, node): + def is_non_empty_tuple(slice_value): + return ( + isinstance(slice_value, Tuple) + and slice_value.elts + ) + + self.set_precedence(_Precedence.ATOM, node.value) + self.traverse(node.value) + with self.delimit("[", "]"): + if is_non_empty_tuple(node.slice): + # parentheses can be omitted if the tuple isn't empty + self.items_view(self.traverse, node.slice.elts) + else: + self.traverse(node.slice) + + def visit_Starred(self, node): + self.write("*") + self.set_precedence(_Precedence.EXPR, node.value) + self.traverse(node.value) + + def visit_Ellipsis(self, node): + self.write("...") + + def visit_Slice(self, node): + if node.lower: + self.traverse(node.lower) + self.write(":") + if node.upper: + self.traverse(node.upper) + if node.step: + self.write(":") + self.traverse(node.step) + + def visit_Match(self, node): + self.fill("match ", allow_semicolon=False) + self.traverse(node.subject) + with self.block(): + for case in node.cases: + self.traverse(case) + + def visit_arg(self, node): + self.write(node.arg) + if node.annotation: + self.write(": ") + self.traverse(node.annotation) + + def visit_arguments(self, node): + first = True + # normal arguments + all_args = node.posonlyargs + node.args + defaults = [None] * (len(all_args) - len(node.defaults)) + node.defaults + for index, elements in enumerate(zip(all_args, defaults), 1): + a, d = elements + if first: + first = False + else: + self.write(", ") + self.traverse(a) + if d: + self.write("=") + self.traverse(d) + if index == len(node.posonlyargs): + self.write(", /") + + # varargs, or bare '*' if no varargs but keyword-only arguments present + if node.vararg or node.kwonlyargs: + if first: + first = False + else: + self.write(", ") + self.write("*") + if node.vararg: + self.write(node.vararg.arg) + if node.vararg.annotation: + self.write(": ") + self.traverse(node.vararg.annotation) + + # keyword-only arguments + if node.kwonlyargs: + for a, d in zip(node.kwonlyargs, node.kw_defaults): + self.write(", ") + self.traverse(a) + if d: + self.write("=") + self.traverse(d) + + # kwargs + if node.kwarg: + if first: + first = False + else: + self.write(", ") + self.write("**" + node.kwarg.arg) + if node.kwarg.annotation: + self.write(": ") + self.traverse(node.kwarg.annotation) + + def visit_keyword(self, node): + if node.arg is None: + self.write("**") + else: + self.write(node.arg) + self.write("=") + self.traverse(node.value) + + def visit_Lambda(self, node): + with self.require_parens(_Precedence.TEST, node): + self.write("lambda") + with self.buffered() as buffer: + self.traverse(node.args) + if buffer: + self.write(" ", *buffer) + self.write(": ") + self.set_precedence(_Precedence.TEST, node.body) + self.traverse(node.body) + + def visit_alias(self, node): + self.write(node.name) + if node.asname: + self.write(" as " + node.asname) + + def visit_withitem(self, node): + self.traverse(node.context_expr) + if node.optional_vars: + self.write(" as ") + self.traverse(node.optional_vars) + + def visit_match_case(self, node): + self.fill("case ", allow_semicolon=False) + self.traverse(node.pattern) + if node.guard: + self.write(" if ") + self.traverse(node.guard) + with self.block(): + self.traverse(node.body) + + def visit_MatchValue(self, node): + self.traverse(node.value) + + def visit_MatchSingleton(self, node): + self._write_constant(node.value) + + def visit_MatchSequence(self, node): + with self.delimit("[", "]"): + self.interleave( + lambda: self.write(", "), self.traverse, node.patterns + ) + + def visit_MatchStar(self, node): + name = node.name + if name is None: + name = "_" + self.write(f"*{name}") + + def visit_MatchMapping(self, node): + def write_key_pattern_pair(pair): + k, p = pair + self.traverse(k) + self.write(": ") + self.traverse(p) + + with self.delimit("{", "}"): + keys = node.keys + self.interleave( + lambda: self.write(", "), + write_key_pattern_pair, + zip(keys, node.patterns, strict=True), + ) + rest = node.rest + if rest is not None: + if keys: + self.write(", ") + self.write(f"**{rest}") + + def visit_MatchClass(self, node): + self.set_precedence(_Precedence.ATOM, node.cls) + self.traverse(node.cls) + with self.delimit("(", ")"): + patterns = node.patterns + self.interleave( + lambda: self.write(", "), self.traverse, patterns + ) + attrs = node.kwd_attrs + if attrs: + def write_attr_pattern(pair): + attr, pattern = pair + self.write(f"{attr}=") + self.traverse(pattern) + + if patterns: + self.write(", ") + self.interleave( + lambda: self.write(", "), + write_attr_pattern, + zip(attrs, node.kwd_patterns, strict=True), + ) + + def visit_MatchAs(self, node): + name = node.name + pattern = node.pattern + if name is None: + self.write("_") + elif pattern is None: + self.write(node.name) + else: + with self.require_parens(_Precedence.TEST, node): + self.set_precedence(_Precedence.BOR, node.pattern) + self.traverse(node.pattern) + self.write(f" as {node.name}") + + def visit_MatchOr(self, node): + with self.require_parens(_Precedence.BOR, node): + self.set_precedence(_Precedence.BOR.next(), *node.patterns) + self.interleave(lambda: self.write(" | "), self.traverse, node.patterns) + + +def unparse(ast_obj): + unparser = _Unparser() + return unparser.visit(ast_obj) +unparse.__module__ = 'ast' # backwards compatibility diff --git a/Lib/ast.py b/Lib/ast.py index cb1f8dfe128ead..8be4f68455150a 100644 --- a/Lib/ast.py +++ b/Lib/ast.py @@ -26,8 +26,6 @@ """ import sys from _ast import * -from contextlib import contextmanager, nullcontext -from enum import IntEnum, auto, _simple_enum def parse(source, filename='', mode='exec', *, @@ -623,1147 +621,6 @@ class Param(expr_context): """Deprecated AST node class. Unused in Python 3.""" -# Large float and imaginary literals get turned into infinities in the AST. -# We unparse those infinities to INFSTR. -_INFSTR = "1e" + repr(sys.float_info.max_10_exp + 1) - -@_simple_enum(IntEnum) -class _Precedence: - """Precedence table that originated from python grammar.""" - - NAMED_EXPR = auto() # := - TUPLE = auto() # , - YIELD = auto() # 'yield', 'yield from' - TEST = auto() # 'if'-'else', 'lambda' - OR = auto() # 'or' - AND = auto() # 'and' - NOT = auto() # 'not' - CMP = auto() # '<', '>', '==', '>=', '<=', '!=', - # 'in', 'not in', 'is', 'is not' - EXPR = auto() - BOR = EXPR # '|' - BXOR = auto() # '^' - BAND = auto() # '&' - SHIFT = auto() # '<<', '>>' - ARITH = auto() # '+', '-' - TERM = auto() # '*', '@', '/', '%', '//' - FACTOR = auto() # unary '+', '-', '~' - POWER = auto() # '**' - AWAIT = auto() # 'await' - ATOM = auto() - - def next(self): - try: - return self.__class__(self + 1) - except ValueError: - return self - - -_SINGLE_QUOTES = ("'", '"') -_MULTI_QUOTES = ('"""', "'''") -_ALL_QUOTES = (*_SINGLE_QUOTES, *_MULTI_QUOTES) - -class _Unparser(NodeVisitor): - """Methods in this class recursively traverse an AST and - output source code for the abstract syntax; original formatting - is disregarded.""" - - def __init__(self): - self._source = [] - self._precedences = {} - self._type_ignores = {} - self._indent = 0 - self._in_try_star = False - self._in_interactive = False - - def interleave(self, inter, f, seq): - """Call f on each item in seq, calling inter() in between.""" - seq = iter(seq) - try: - f(next(seq)) - except StopIteration: - pass - else: - for x in seq: - inter() - f(x) - - def items_view(self, traverser, items): - """Traverse and separate the given *items* with a comma and append it to - the buffer. If *items* is a single item sequence, a trailing comma - will be added.""" - if len(items) == 1: - traverser(items[0]) - self.write(",") - else: - self.interleave(lambda: self.write(", "), traverser, items) - - def maybe_newline(self): - """Adds a newline if it isn't the start of generated source""" - if self._source: - self.write("\n") - - def maybe_semicolon(self): - """Adds a "; " delimiter if it isn't the start of generated source""" - if self._source: - self.write("; ") - - def fill(self, text="", *, allow_semicolon=True): - """Indent a piece of text and append it, according to the current - indentation level, or only delineate with semicolon if applicable""" - if self._in_interactive and not self._indent and allow_semicolon: - self.maybe_semicolon() - self.write(text) - else: - self.maybe_newline() - self.write(" " * self._indent + text) - - def write(self, *text): - """Add new source parts""" - self._source.extend(text) - - @contextmanager - def buffered(self, buffer = None): - if buffer is None: - buffer = [] - - original_source = self._source - self._source = buffer - yield buffer - self._source = original_source - - @contextmanager - def block(self, *, extra = None): - """A context manager for preparing the source for blocks. It adds - the character':', increases the indentation on enter and decreases - the indentation on exit. If *extra* is given, it will be directly - appended after the colon character. - """ - self.write(":") - if extra: - self.write(extra) - self._indent += 1 - yield - self._indent -= 1 - - @contextmanager - def delimit(self, start, end): - """A context manager for preparing the source for expressions. It adds - *start* to the buffer and enters, after exit it adds *end*.""" - - self.write(start) - yield - self.write(end) - - def delimit_if(self, start, end, condition): - if condition: - return self.delimit(start, end) - else: - return nullcontext() - - def require_parens(self, precedence, node): - """Shortcut to adding precedence related parens""" - return self.delimit_if("(", ")", self.get_precedence(node) > precedence) - - def get_precedence(self, node): - return self._precedences.get(node, _Precedence.TEST) - - def set_precedence(self, precedence, *nodes): - for node in nodes: - self._precedences[node] = precedence - - def get_raw_docstring(self, node): - """If a docstring node is found in the body of the *node* parameter, - return that docstring node, None otherwise. - - Logic mirrored from ``_PyAST_GetDocString``.""" - if not isinstance( - node, (AsyncFunctionDef, FunctionDef, ClassDef, Module) - ) or len(node.body) < 1: - return None - node = node.body[0] - if not isinstance(node, Expr): - return None - node = node.value - if isinstance(node, Constant) and isinstance(node.value, str): - return node - - def get_type_comment(self, node): - comment = self._type_ignores.get(node.lineno) or node.type_comment - if comment is not None: - return f" # type: {comment}" - - def traverse(self, node): - if isinstance(node, list): - for item in node: - self.traverse(item) - else: - super().visit(node) - - # Note: as visit() resets the output text, do NOT rely on - # NodeVisitor.generic_visit to handle any nodes (as it calls back in to - # the subclass visit() method, which resets self._source to an empty list) - def visit(self, node): - """Outputs a source code string that, if converted back to an ast - (using ast.parse) will generate an AST equivalent to *node*""" - self._source = [] - self.traverse(node) - return "".join(self._source) - - def _write_docstring_and_traverse_body(self, node): - if (docstring := self.get_raw_docstring(node)): - self._write_docstring(docstring) - self.traverse(node.body[1:]) - else: - self.traverse(node.body) - - def visit_Module(self, node): - self._type_ignores = { - ignore.lineno: f"ignore{ignore.tag}" - for ignore in node.type_ignores - } - try: - self._write_docstring_and_traverse_body(node) - finally: - self._type_ignores.clear() - - def visit_Interactive(self, node): - self._in_interactive = True - try: - self._write_docstring_and_traverse_body(node) - finally: - self._in_interactive = False - - def visit_FunctionType(self, node): - with self.delimit("(", ")"): - self.interleave( - lambda: self.write(", "), self.traverse, node.argtypes - ) - - self.write(" -> ") - self.traverse(node.returns) - - def visit_Expr(self, node): - self.fill() - self.set_precedence(_Precedence.YIELD, node.value) - self.traverse(node.value) - - def visit_NamedExpr(self, node): - with self.require_parens(_Precedence.NAMED_EXPR, node): - self.set_precedence(_Precedence.ATOM, node.target, node.value) - self.traverse(node.target) - self.write(" := ") - self.traverse(node.value) - - def visit_Import(self, node): - self.fill("import ") - self.interleave(lambda: self.write(", "), self.traverse, node.names) - - def visit_ImportFrom(self, node): - self.fill("from ") - self.write("." * (node.level or 0)) - if node.module: - self.write(node.module) - self.write(" import ") - self.interleave(lambda: self.write(", "), self.traverse, node.names) - - def visit_Assign(self, node): - self.fill() - for target in node.targets: - self.set_precedence(_Precedence.TUPLE, target) - self.traverse(target) - self.write(" = ") - self.traverse(node.value) - if type_comment := self.get_type_comment(node): - self.write(type_comment) - - def visit_AugAssign(self, node): - self.fill() - self.traverse(node.target) - self.write(" " + self.binop[node.op.__class__.__name__] + "= ") - self.traverse(node.value) - - def visit_AnnAssign(self, node): - self.fill() - with self.delimit_if("(", ")", not node.simple and isinstance(node.target, Name)): - self.traverse(node.target) - self.write(": ") - self.traverse(node.annotation) - if node.value: - self.write(" = ") - self.traverse(node.value) - - def visit_Return(self, node): - self.fill("return") - if node.value: - self.write(" ") - self.traverse(node.value) - - def visit_Pass(self, node): - self.fill("pass") - - def visit_Break(self, node): - self.fill("break") - - def visit_Continue(self, node): - self.fill("continue") - - def visit_Delete(self, node): - self.fill("del ") - self.interleave(lambda: self.write(", "), self.traverse, node.targets) - - def visit_Assert(self, node): - self.fill("assert ") - self.traverse(node.test) - if node.msg: - self.write(", ") - self.traverse(node.msg) - - def visit_Global(self, node): - self.fill("global ") - self.interleave(lambda: self.write(", "), self.write, node.names) - - def visit_Nonlocal(self, node): - self.fill("nonlocal ") - self.interleave(lambda: self.write(", "), self.write, node.names) - - def visit_Await(self, node): - with self.require_parens(_Precedence.AWAIT, node): - self.write("await") - if node.value: - self.write(" ") - self.set_precedence(_Precedence.ATOM, node.value) - self.traverse(node.value) - - def visit_Yield(self, node): - with self.require_parens(_Precedence.YIELD, node): - self.write("yield") - if node.value: - self.write(" ") - self.set_precedence(_Precedence.ATOM, node.value) - self.traverse(node.value) - - def visit_YieldFrom(self, node): - with self.require_parens(_Precedence.YIELD, node): - self.write("yield from ") - if not node.value: - raise ValueError("Node can't be used without a value attribute.") - self.set_precedence(_Precedence.ATOM, node.value) - self.traverse(node.value) - - def visit_Raise(self, node): - self.fill("raise") - if not node.exc: - if node.cause: - raise ValueError(f"Node can't use cause without an exception.") - return - self.write(" ") - self.traverse(node.exc) - if node.cause: - self.write(" from ") - self.traverse(node.cause) - - def do_visit_try(self, node): - self.fill("try", allow_semicolon=False) - with self.block(): - self.traverse(node.body) - for ex in node.handlers: - self.traverse(ex) - if node.orelse: - self.fill("else", allow_semicolon=False) - with self.block(): - self.traverse(node.orelse) - if node.finalbody: - self.fill("finally", allow_semicolon=False) - with self.block(): - self.traverse(node.finalbody) - - def visit_Try(self, node): - prev_in_try_star = self._in_try_star - try: - self._in_try_star = False - self.do_visit_try(node) - finally: - self._in_try_star = prev_in_try_star - - def visit_TryStar(self, node): - prev_in_try_star = self._in_try_star - try: - self._in_try_star = True - self.do_visit_try(node) - finally: - self._in_try_star = prev_in_try_star - - def visit_ExceptHandler(self, node): - self.fill("except*" if self._in_try_star else "except", allow_semicolon=False) - if node.type: - self.write(" ") - self.traverse(node.type) - if node.name: - self.write(" as ") - self.write(node.name) - with self.block(): - self.traverse(node.body) - - def visit_ClassDef(self, node): - self.maybe_newline() - for deco in node.decorator_list: - self.fill("@", allow_semicolon=False) - self.traverse(deco) - self.fill("class " + node.name, allow_semicolon=False) - if hasattr(node, "type_params"): - self._type_params_helper(node.type_params) - with self.delimit_if("(", ")", condition = node.bases or node.keywords): - comma = False - for e in node.bases: - if comma: - self.write(", ") - else: - comma = True - self.traverse(e) - for e in node.keywords: - if comma: - self.write(", ") - else: - comma = True - self.traverse(e) - - with self.block(): - self._write_docstring_and_traverse_body(node) - - def visit_FunctionDef(self, node): - self._function_helper(node, "def") - - def visit_AsyncFunctionDef(self, node): - self._function_helper(node, "async def") - - def _function_helper(self, node, fill_suffix): - self.maybe_newline() - for deco in node.decorator_list: - self.fill("@", allow_semicolon=False) - self.traverse(deco) - def_str = fill_suffix + " " + node.name - self.fill(def_str, allow_semicolon=False) - if hasattr(node, "type_params"): - self._type_params_helper(node.type_params) - with self.delimit("(", ")"): - self.traverse(node.args) - if node.returns: - self.write(" -> ") - self.traverse(node.returns) - with self.block(extra=self.get_type_comment(node)): - self._write_docstring_and_traverse_body(node) - - def _type_params_helper(self, type_params): - if type_params is not None and len(type_params) > 0: - with self.delimit("[", "]"): - self.interleave(lambda: self.write(", "), self.traverse, type_params) - - def visit_TypeVar(self, node): - self.write(node.name) - if node.bound: - self.write(": ") - self.traverse(node.bound) - if node.default_value: - self.write(" = ") - self.traverse(node.default_value) - - def visit_TypeVarTuple(self, node): - self.write("*" + node.name) - if node.default_value: - self.write(" = ") - self.traverse(node.default_value) - - def visit_ParamSpec(self, node): - self.write("**" + node.name) - if node.default_value: - self.write(" = ") - self.traverse(node.default_value) - - def visit_TypeAlias(self, node): - self.fill("type ") - self.traverse(node.name) - self._type_params_helper(node.type_params) - self.write(" = ") - self.traverse(node.value) - - def visit_For(self, node): - self._for_helper("for ", node) - - def visit_AsyncFor(self, node): - self._for_helper("async for ", node) - - def _for_helper(self, fill, node): - self.fill(fill, allow_semicolon=False) - self.set_precedence(_Precedence.TUPLE, node.target) - self.traverse(node.target) - self.write(" in ") - self.traverse(node.iter) - with self.block(extra=self.get_type_comment(node)): - self.traverse(node.body) - if node.orelse: - self.fill("else", allow_semicolon=False) - with self.block(): - self.traverse(node.orelse) - - def visit_If(self, node): - self.fill("if ", allow_semicolon=False) - self.traverse(node.test) - with self.block(): - self.traverse(node.body) - # collapse nested ifs into equivalent elifs. - while node.orelse and len(node.orelse) == 1 and isinstance(node.orelse[0], If): - node = node.orelse[0] - self.fill("elif ", allow_semicolon=False) - self.traverse(node.test) - with self.block(): - self.traverse(node.body) - # final else - if node.orelse: - self.fill("else", allow_semicolon=False) - with self.block(): - self.traverse(node.orelse) - - def visit_While(self, node): - self.fill("while ", allow_semicolon=False) - self.traverse(node.test) - with self.block(): - self.traverse(node.body) - if node.orelse: - self.fill("else", allow_semicolon=False) - with self.block(): - self.traverse(node.orelse) - - def visit_With(self, node): - self.fill("with ", allow_semicolon=False) - self.interleave(lambda: self.write(", "), self.traverse, node.items) - with self.block(extra=self.get_type_comment(node)): - self.traverse(node.body) - - def visit_AsyncWith(self, node): - self.fill("async with ", allow_semicolon=False) - self.interleave(lambda: self.write(", "), self.traverse, node.items) - with self.block(extra=self.get_type_comment(node)): - self.traverse(node.body) - - def _str_literal_helper( - self, string, *, quote_types=_ALL_QUOTES, escape_special_whitespace=False - ): - """Helper for writing string literals, minimizing escapes. - Returns the tuple (string literal to write, possible quote types). - """ - def escape_char(c): - # \n and \t are non-printable, but we only escape them if - # escape_special_whitespace is True - if not escape_special_whitespace and c in "\n\t": - return c - # Always escape backslashes and other non-printable characters - if c == "\\" or not c.isprintable(): - return c.encode("unicode_escape").decode("ascii") - return c - - escaped_string = "".join(map(escape_char, string)) - possible_quotes = quote_types - if "\n" in escaped_string: - possible_quotes = [q for q in possible_quotes if q in _MULTI_QUOTES] - possible_quotes = [q for q in possible_quotes if q not in escaped_string] - if not possible_quotes: - # If there aren't any possible_quotes, fallback to using repr - # on the original string. Try to use a quote from quote_types, - # e.g., so that we use triple quotes for docstrings. - string = repr(string) - quote = next((q for q in quote_types if string[0] in q), string[0]) - return string[1:-1], [quote] - if escaped_string: - # Sort so that we prefer '''"''' over """\"""" - possible_quotes.sort(key=lambda q: q[0] == escaped_string[-1]) - # If we're using triple quotes and we'd need to escape a final - # quote, escape it - if possible_quotes[0][0] == escaped_string[-1]: - assert len(possible_quotes[0]) == 3 - escaped_string = escaped_string[:-1] + "\\" + escaped_string[-1] - return escaped_string, possible_quotes - - def _write_str_avoiding_backslashes(self, string, *, quote_types=_ALL_QUOTES): - """Write string literal value with a best effort attempt to avoid backslashes.""" - string, quote_types = self._str_literal_helper(string, quote_types=quote_types) - quote_type = quote_types[0] - self.write(f"{quote_type}{string}{quote_type}") - - def visit_JoinedStr(self, node): - self.write("f") - - fstring_parts = [] - for value in node.values: - with self.buffered() as buffer: - self._write_fstring_inner(value) - fstring_parts.append( - ("".join(buffer), isinstance(value, Constant)) - ) - - new_fstring_parts = [] - quote_types = list(_ALL_QUOTES) - fallback_to_repr = False - for value, is_constant in fstring_parts: - if is_constant: - value, new_quote_types = self._str_literal_helper( - value, - quote_types=quote_types, - escape_special_whitespace=True, - ) - if set(new_quote_types).isdisjoint(quote_types): - fallback_to_repr = True - break - quote_types = new_quote_types - else: - if "\n" in value: - quote_types = [q for q in quote_types if q in _MULTI_QUOTES] - assert quote_types - - new_quote_types = [q for q in quote_types if q not in value] - if new_quote_types: - quote_types = new_quote_types - new_fstring_parts.append(value) - - if fallback_to_repr: - # If we weren't able to find a quote type that works for all parts - # of the JoinedStr, fallback to using repr and triple single quotes. - quote_types = ["'''"] - new_fstring_parts.clear() - for value, is_constant in fstring_parts: - if is_constant: - value = repr('"' + value) # force repr to use single quotes - expected_prefix = "'\"" - assert value.startswith(expected_prefix), repr(value) - value = value[len(expected_prefix):-1] - new_fstring_parts.append(value) - - value = "".join(new_fstring_parts) - quote_type = quote_types[0] - self.write(f"{quote_type}{value}{quote_type}") - - def _write_fstring_inner(self, node, is_format_spec=False): - if isinstance(node, JoinedStr): - # for both the f-string itself, and format_spec - for value in node.values: - self._write_fstring_inner(value, is_format_spec=is_format_spec) - elif isinstance(node, Constant) and isinstance(node.value, str): - value = node.value.replace("{", "{{").replace("}", "}}") - - if is_format_spec: - value = value.replace("\\", "\\\\") - value = value.replace("'", "\\'") - value = value.replace('"', '\\"') - value = value.replace("\n", "\\n") - self.write(value) - elif isinstance(node, FormattedValue): - self.visit_FormattedValue(node) - else: - raise ValueError(f"Unexpected node inside JoinedStr, {node!r}") - - def visit_FormattedValue(self, node): - def unparse_inner(inner): - unparser = type(self)() - unparser.set_precedence(_Precedence.TEST.next(), inner) - return unparser.visit(inner) - - with self.delimit("{", "}"): - expr = unparse_inner(node.value) - if expr.startswith("{"): - # Separate pair of opening brackets as "{ {" - self.write(" ") - self.write(expr) - if node.conversion != -1: - self.write(f"!{chr(node.conversion)}") - if node.format_spec: - self.write(":") - self._write_fstring_inner(node.format_spec, is_format_spec=True) - - def visit_Name(self, node): - self.write(node.id) - - def _write_docstring(self, node): - self.fill(allow_semicolon=False) - if node.kind == "u": - self.write("u") - self._write_str_avoiding_backslashes(node.value, quote_types=_MULTI_QUOTES) - - def _write_constant(self, value): - if isinstance(value, (float, complex)): - # Substitute overflowing decimal literal for AST infinities, - # and inf - inf for NaNs. - self.write( - repr(value) - .replace("inf", _INFSTR) - .replace("nan", f"({_INFSTR}-{_INFSTR})") - ) - else: - self.write(repr(value)) - - def visit_Constant(self, node): - value = node.value - if isinstance(value, tuple): - with self.delimit("(", ")"): - self.items_view(self._write_constant, value) - elif value is ...: - self.write("...") - else: - if node.kind == "u": - self.write("u") - self._write_constant(node.value) - - def visit_List(self, node): - with self.delimit("[", "]"): - self.interleave(lambda: self.write(", "), self.traverse, node.elts) - - def visit_ListComp(self, node): - with self.delimit("[", "]"): - self.traverse(node.elt) - for gen in node.generators: - self.traverse(gen) - - def visit_GeneratorExp(self, node): - with self.delimit("(", ")"): - self.traverse(node.elt) - for gen in node.generators: - self.traverse(gen) - - def visit_SetComp(self, node): - with self.delimit("{", "}"): - self.traverse(node.elt) - for gen in node.generators: - self.traverse(gen) - - def visit_DictComp(self, node): - with self.delimit("{", "}"): - self.traverse(node.key) - self.write(": ") - self.traverse(node.value) - for gen in node.generators: - self.traverse(gen) - - def visit_comprehension(self, node): - if node.is_async: - self.write(" async for ") - else: - self.write(" for ") - self.set_precedence(_Precedence.TUPLE, node.target) - self.traverse(node.target) - self.write(" in ") - self.set_precedence(_Precedence.TEST.next(), node.iter, *node.ifs) - self.traverse(node.iter) - for if_clause in node.ifs: - self.write(" if ") - self.traverse(if_clause) - - def visit_IfExp(self, node): - with self.require_parens(_Precedence.TEST, node): - self.set_precedence(_Precedence.TEST.next(), node.body, node.test) - self.traverse(node.body) - self.write(" if ") - self.traverse(node.test) - self.write(" else ") - self.set_precedence(_Precedence.TEST, node.orelse) - self.traverse(node.orelse) - - def visit_Set(self, node): - if node.elts: - with self.delimit("{", "}"): - self.interleave(lambda: self.write(", "), self.traverse, node.elts) - else: - # `{}` would be interpreted as a dictionary literal, and - # `set` might be shadowed. Thus: - self.write('{*()}') - - def visit_Dict(self, node): - def write_key_value_pair(k, v): - self.traverse(k) - self.write(": ") - self.traverse(v) - - def write_item(item): - k, v = item - if k is None: - # for dictionary unpacking operator in dicts {**{'y': 2}} - # see PEP 448 for details - self.write("**") - self.set_precedence(_Precedence.EXPR, v) - self.traverse(v) - else: - write_key_value_pair(k, v) - - with self.delimit("{", "}"): - self.interleave( - lambda: self.write(", "), write_item, zip(node.keys, node.values) - ) - - def visit_Tuple(self, node): - with self.delimit_if( - "(", - ")", - len(node.elts) == 0 or self.get_precedence(node) > _Precedence.TUPLE - ): - self.items_view(self.traverse, node.elts) - - unop = {"Invert": "~", "Not": "not", "UAdd": "+", "USub": "-"} - unop_precedence = { - "not": _Precedence.NOT, - "~": _Precedence.FACTOR, - "+": _Precedence.FACTOR, - "-": _Precedence.FACTOR, - } - - def visit_UnaryOp(self, node): - operator = self.unop[node.op.__class__.__name__] - operator_precedence = self.unop_precedence[operator] - with self.require_parens(operator_precedence, node): - self.write(operator) - # factor prefixes (+, -, ~) shouldn't be separated - # from the value they belong, (e.g: +1 instead of + 1) - if operator_precedence is not _Precedence.FACTOR: - self.write(" ") - self.set_precedence(operator_precedence, node.operand) - self.traverse(node.operand) - - binop = { - "Add": "+", - "Sub": "-", - "Mult": "*", - "MatMult": "@", - "Div": "/", - "Mod": "%", - "LShift": "<<", - "RShift": ">>", - "BitOr": "|", - "BitXor": "^", - "BitAnd": "&", - "FloorDiv": "//", - "Pow": "**", - } - - binop_precedence = { - "+": _Precedence.ARITH, - "-": _Precedence.ARITH, - "*": _Precedence.TERM, - "@": _Precedence.TERM, - "/": _Precedence.TERM, - "%": _Precedence.TERM, - "<<": _Precedence.SHIFT, - ">>": _Precedence.SHIFT, - "|": _Precedence.BOR, - "^": _Precedence.BXOR, - "&": _Precedence.BAND, - "//": _Precedence.TERM, - "**": _Precedence.POWER, - } - - binop_rassoc = frozenset(("**",)) - def visit_BinOp(self, node): - operator = self.binop[node.op.__class__.__name__] - operator_precedence = self.binop_precedence[operator] - with self.require_parens(operator_precedence, node): - if operator in self.binop_rassoc: - left_precedence = operator_precedence.next() - right_precedence = operator_precedence - else: - left_precedence = operator_precedence - right_precedence = operator_precedence.next() - - self.set_precedence(left_precedence, node.left) - self.traverse(node.left) - self.write(f" {operator} ") - self.set_precedence(right_precedence, node.right) - self.traverse(node.right) - - cmpops = { - "Eq": "==", - "NotEq": "!=", - "Lt": "<", - "LtE": "<=", - "Gt": ">", - "GtE": ">=", - "Is": "is", - "IsNot": "is not", - "In": "in", - "NotIn": "not in", - } - - def visit_Compare(self, node): - with self.require_parens(_Precedence.CMP, node): - self.set_precedence(_Precedence.CMP.next(), node.left, *node.comparators) - self.traverse(node.left) - for o, e in zip(node.ops, node.comparators): - self.write(" " + self.cmpops[o.__class__.__name__] + " ") - self.traverse(e) - - boolops = {"And": "and", "Or": "or"} - boolop_precedence = {"and": _Precedence.AND, "or": _Precedence.OR} - - def visit_BoolOp(self, node): - operator = self.boolops[node.op.__class__.__name__] - operator_precedence = self.boolop_precedence[operator] - - def increasing_level_traverse(node): - nonlocal operator_precedence - operator_precedence = operator_precedence.next() - self.set_precedence(operator_precedence, node) - self.traverse(node) - - with self.require_parens(operator_precedence, node): - s = f" {operator} " - self.interleave(lambda: self.write(s), increasing_level_traverse, node.values) - - def visit_Attribute(self, node): - self.set_precedence(_Precedence.ATOM, node.value) - self.traverse(node.value) - # Special case: 3.__abs__() is a syntax error, so if node.value - # is an integer literal then we need to either parenthesize - # it or add an extra space to get 3 .__abs__(). - if isinstance(node.value, Constant) and isinstance(node.value.value, int): - self.write(" ") - self.write(".") - self.write(node.attr) - - def visit_Call(self, node): - self.set_precedence(_Precedence.ATOM, node.func) - self.traverse(node.func) - with self.delimit("(", ")"): - comma = False - for e in node.args: - if comma: - self.write(", ") - else: - comma = True - self.traverse(e) - for e in node.keywords: - if comma: - self.write(", ") - else: - comma = True - self.traverse(e) - - def visit_Subscript(self, node): - def is_non_empty_tuple(slice_value): - return ( - isinstance(slice_value, Tuple) - and slice_value.elts - ) - - self.set_precedence(_Precedence.ATOM, node.value) - self.traverse(node.value) - with self.delimit("[", "]"): - if is_non_empty_tuple(node.slice): - # parentheses can be omitted if the tuple isn't empty - self.items_view(self.traverse, node.slice.elts) - else: - self.traverse(node.slice) - - def visit_Starred(self, node): - self.write("*") - self.set_precedence(_Precedence.EXPR, node.value) - self.traverse(node.value) - - def visit_Ellipsis(self, node): - self.write("...") - - def visit_Slice(self, node): - if node.lower: - self.traverse(node.lower) - self.write(":") - if node.upper: - self.traverse(node.upper) - if node.step: - self.write(":") - self.traverse(node.step) - - def visit_Match(self, node): - self.fill("match ", allow_semicolon=False) - self.traverse(node.subject) - with self.block(): - for case in node.cases: - self.traverse(case) - - def visit_arg(self, node): - self.write(node.arg) - if node.annotation: - self.write(": ") - self.traverse(node.annotation) - - def visit_arguments(self, node): - first = True - # normal arguments - all_args = node.posonlyargs + node.args - defaults = [None] * (len(all_args) - len(node.defaults)) + node.defaults - for index, elements in enumerate(zip(all_args, defaults), 1): - a, d = elements - if first: - first = False - else: - self.write(", ") - self.traverse(a) - if d: - self.write("=") - self.traverse(d) - if index == len(node.posonlyargs): - self.write(", /") - - # varargs, or bare '*' if no varargs but keyword-only arguments present - if node.vararg or node.kwonlyargs: - if first: - first = False - else: - self.write(", ") - self.write("*") - if node.vararg: - self.write(node.vararg.arg) - if node.vararg.annotation: - self.write(": ") - self.traverse(node.vararg.annotation) - - # keyword-only arguments - if node.kwonlyargs: - for a, d in zip(node.kwonlyargs, node.kw_defaults): - self.write(", ") - self.traverse(a) - if d: - self.write("=") - self.traverse(d) - - # kwargs - if node.kwarg: - if first: - first = False - else: - self.write(", ") - self.write("**" + node.kwarg.arg) - if node.kwarg.annotation: - self.write(": ") - self.traverse(node.kwarg.annotation) - - def visit_keyword(self, node): - if node.arg is None: - self.write("**") - else: - self.write(node.arg) - self.write("=") - self.traverse(node.value) - - def visit_Lambda(self, node): - with self.require_parens(_Precedence.TEST, node): - self.write("lambda") - with self.buffered() as buffer: - self.traverse(node.args) - if buffer: - self.write(" ", *buffer) - self.write(": ") - self.set_precedence(_Precedence.TEST, node.body) - self.traverse(node.body) - - def visit_alias(self, node): - self.write(node.name) - if node.asname: - self.write(" as " + node.asname) - - def visit_withitem(self, node): - self.traverse(node.context_expr) - if node.optional_vars: - self.write(" as ") - self.traverse(node.optional_vars) - - def visit_match_case(self, node): - self.fill("case ", allow_semicolon=False) - self.traverse(node.pattern) - if node.guard: - self.write(" if ") - self.traverse(node.guard) - with self.block(): - self.traverse(node.body) - - def visit_MatchValue(self, node): - self.traverse(node.value) - - def visit_MatchSingleton(self, node): - self._write_constant(node.value) - - def visit_MatchSequence(self, node): - with self.delimit("[", "]"): - self.interleave( - lambda: self.write(", "), self.traverse, node.patterns - ) - - def visit_MatchStar(self, node): - name = node.name - if name is None: - name = "_" - self.write(f"*{name}") - - def visit_MatchMapping(self, node): - def write_key_pattern_pair(pair): - k, p = pair - self.traverse(k) - self.write(": ") - self.traverse(p) - - with self.delimit("{", "}"): - keys = node.keys - self.interleave( - lambda: self.write(", "), - write_key_pattern_pair, - zip(keys, node.patterns, strict=True), - ) - rest = node.rest - if rest is not None: - if keys: - self.write(", ") - self.write(f"**{rest}") - - def visit_MatchClass(self, node): - self.set_precedence(_Precedence.ATOM, node.cls) - self.traverse(node.cls) - with self.delimit("(", ")"): - patterns = node.patterns - self.interleave( - lambda: self.write(", "), self.traverse, patterns - ) - attrs = node.kwd_attrs - if attrs: - def write_attr_pattern(pair): - attr, pattern = pair - self.write(f"{attr}=") - self.traverse(pattern) - - if patterns: - self.write(", ") - self.interleave( - lambda: self.write(", "), - write_attr_pattern, - zip(attrs, node.kwd_patterns, strict=True), - ) - - def visit_MatchAs(self, node): - name = node.name - pattern = node.pattern - if name is None: - self.write("_") - elif pattern is None: - self.write(node.name) - else: - with self.require_parens(_Precedence.TEST, node): - self.set_precedence(_Precedence.BOR, node.pattern) - self.traverse(node.pattern) - self.write(f" as {node.name}") - - def visit_MatchOr(self, node): - with self.require_parens(_Precedence.BOR, node): - self.set_precedence(_Precedence.BOR.next(), *node.patterns) - self.interleave(lambda: self.write(" | "), self.traverse, node.patterns) - - -def unparse(ast_obj): - unparser = _Unparser() - return unparser.visit(ast_obj) - - def main(): import argparse @@ -1794,3 +651,15 @@ def main(): if __name__ == '__main__': main() + +def __dir__(): + dir_ = {n for n in globals() if not n.startswith('_') and n != 'sys'} + return sorted(dir_ | {'unparse'}) + +def __getattr__(name): + if name == 'unparse': + global unparse + from _ast_unparse import unparse + return unparse + + raise AttributeError(f'module {__name__!r} has no attribute {name!r}') diff --git a/Lib/test/test_ast/test_ast.py b/Lib/test/test_ast/test_ast.py index e5fd8f6a295ed2..70fbe792e9bdab 100644 --- a/Lib/test/test_ast/test_ast.py +++ b/Lib/test/test_ast/test_ast.py @@ -1,3 +1,4 @@ +import _ast_unparse import ast import builtins import copy @@ -732,7 +733,7 @@ def next(self): return self.__class__(self + 1) except ValueError: return self - enum._test_simple_enum(_Precedence, ast._Precedence) + enum._test_simple_enum(_Precedence, _ast_unparse._Precedence) @support.cpython_only @skip_wasi_stack_overflow() diff --git a/Misc/NEWS.d/next/Library/2025-03-31-19-19-36.gh-issue-118761.M0yFiZ.rst b/Misc/NEWS.d/next/Library/2025-03-31-19-19-36.gh-issue-118761.M0yFiZ.rst new file mode 100644 index 00000000000000..36225dfcf3c5e6 --- /dev/null +++ b/Misc/NEWS.d/next/Library/2025-03-31-19-19-36.gh-issue-118761.M0yFiZ.rst @@ -0,0 +1,2 @@ +Improve the import time of the :mod:`ast` module by extracting the +:func:`~ast.unparse` function to a helper module. diff --git a/Python/stdlib_module_names.h b/Python/stdlib_module_names.h index 584b050fc4bb6e..ec8976277aad4c 100644 --- a/Python/stdlib_module_names.h +++ b/Python/stdlib_module_names.h @@ -8,6 +8,7 @@ static const char* _Py_stdlib_module_names[] = { "_android_support", "_apple_support", "_ast", +"_ast_unparse", "_asyncio", "_bisect", "_blake2", pFad - Phonifier reborn

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